Urticaria, or hives, are pruritic raised erythematous superficial skin wheals that arise in response to histamine, leukotrienes, prostaglandins, and other substances released by stimulated mast cells. Lesions develop and resolve quickly; individual lesions should resolve in < 24 hours. Urticaria is often associated with hypersensitivity reactions, including anaphylaxis. Symptoms are characterized as acute if they occur daily for < 6 weeks, and chronic if they occur for longer. Triggers can include allergic reactions to drugs, foods, insect stings, and rarely aeroallergens. Urticaria can also be caused by physical stimuli including cold, heat or exercise (cholinergic), pressure, vibration, and sun exposure. Infections including hepatitis, EBV, helminthes, and fungi have been associated with urticaria. Patients with collagen vascular diseases often develop urticaria. Differential diagnosis includes mastocytosis/urticaria pigmentosa, erythema multiforme, bullous skin disorders, or dermatitis herpetiformis. Obtaining a detailed history can help find an etiology. Urticaria that has been occurring for < 6 weeks usually does not require any laboratory workup. Laboratory tests may be done as indicated for chronic urticaria. Helminth infections would be associated with very high eosinophilia.
Attempt to identify the trigger based on a thorough history. Advise patients to discontinue or avoid the offending agent, if known. The main form of treatment includes H1 blockers (eg, diphenhydramine) given intravenously (IV) or orally. Second-generation antihistamines (eg, cetirizine) can be used once or twice a day until symptoms resolve. H2 blockers (eg, cimetidine, ranitidine) may be combined with H1 blockers. For patients with severe urticaria, interventions may include epinephrine given subcutaneously, corticosteroids given IV as hydrocortisone or methylprednisolone, or oral prednisone given first bolus followed by once-daily dose. Suspected anaphylaxis should be treated accordingly. Patients should be educated and sent home with injectable epinephrine. Urticaria can be very frustrating for the patient, and referral to an allergist can often help with management and investigation for the trigger.
Urticaria is characterized by erythematosus, edematous lesions that are pruritic and evanescent.
If the lesions last longer than 24 hours, leave a mark, or are painful rather than pruritic, refer the patient for skin biopsy to rule out urticarial vasculitis.
The underlying cause for chronic urticaria is rarely found.
Figure 7.3 ▪ Dermographism.
This “rash” was produced within 3 minutes of stroking the skin with a tongue blade. Dermographism (ability to write on the skin) is an example of physical urticaria. Triggering factors may include contact with clothing, towels, or sheets. It can also occur as an isolated disorder. Linear pruritic wheals appear on skin within 2 to 5 minutes of stroking and usually resolve within 30 minutes to 3 hours. Most patients are without any systemic symptoms. (Photo contributor: Binita R. Shah, MD.)
The authors acknowledge the special contributions of Binita R. Shah, MD, to prior edition.
Angioedema is a swelling of the deeper dermal subcutaneous tissue. Commonly affected areas include the extremities and face, specifically lips and tongue. Airway involvement may occur and is life-threatening. It is often painful rather than pruritic. Angioedema occurs secondary to release of various mediators including histamine, leukotrienes, and prostaglandins from stimulated mast cells or abnormalities in the complement or arachidonic acid pathways. Angioedema, like urticaria is often associated with hypersensitivity reactions, including anaphylaxis. Chronic angioedema describes symptoms that last longer than 6 weeks. Triggers may include allergic reactions to drugs, foods, and insect stings. Certain medications including ACE inhibitors often cause a non–IgE-mediated reaction manifesting as angioedema. Hereditary angioedema presents as spontaneous recurrent attacks of angioedema often triggered by trauma. There are 3 genetic types, the most common is inherited in an autosomal dominant fashion; however, many patients have spontaneous mutations. This disorder is characterized by abnormal levels or function of C1 esterase inhibitor. Patients often present with initial attacks around puberty and many have isolated visceral angioedema that mimics an acute abdomen. Patients often report episodes of swelling worsening over a period of 12 to 24 hours, usually with resolution within 3 to 5 days. The swelling may migrate to different areas. The edema is usually unresponsive to antihistamines. Attacks are usually periodic and are commonly followed by weeks of remission. Laboratory screening is accomplished by obtaining a C4 level that is low during attacks. Further testing with C1 esterase inhibitor level or functional C1 esterase inhibitor assays can be used for confirmatory diagnosis if initial C4 screen is low.
Figure 7.4 ▪ Angioedema.
Swelling of the ear (A), periorbital area (B) following mosquito bites and swelling of the lips and face with an urticarial rash (C), following ingestion of shellfish were the presenting complaints. Angioedema usually involves the loose connective tissues of the ear or the periorbital or perioral areas, but may involve the oropharynx or extremities. The edema is nonpitting, well-circumscribed, and usually nonpruritic (unless coexisting with urticaria). (Photo contributor: Binita R. Shah, MD.)
Anaphylaxis should be treated emergently. For hereditary angioedema, treatment includes supportive care and pain management. Patients presenting with breathing difficulty due to laryngeal swelling may need elective intubation. Epinephrine or corticosteroids may help some patients. Refer the patient to an allergist for continuity of care and management. Long-term treatments include synthetic androgen steroids, for example, danazol and stanozolol, which may be considered in older children after careful consideration of the side effects.
Serum sickness is an immune complex–meditated type III hypersensitivity reaction, produced by exposure to a variety of agents. It is characterized by fever, joint involvement, skin rash, lymphadenopathy, splenomegaly, arthralgia, and proteinuria. The classic serum sickness is rarely seen nowadays and can be caused by blood products (eg, human γ-globulin) and animal-derived serum (eg, antitoxins for treatment of spider and snake envenomations [eg, Crotalidae antivenin], antitoxins for clostridial intoxication [eg, botulism, gas gangrene], and antirabies serum). Diagnosis is suspected based on history of an exposure to a foreign antigen.
Serum sickness–like reaction is a drug reaction that can be seen 1 to 3 weeks, after exposure to the etiologic agent. The mechanism of this reaction is not well understood. The most commonly associated medication in children is cefaclor. Other medications have been implicated, including penicillins, cephalosporins, sulfa drugs, minocycline, propranolol, bupropion, and griseofulvin. Cutaneous morphology can be urticarial, morbiliform, or erythema multiforme-like. Other features are joint swellings, arthralgia, fever, and lymphadenopathy. Unlike classic serum sickness, frank arthritis, hepatic, renal and CNS involvement are rarely seen. Skin biopsy is not necessary to make the diagnosis. Differential diagnosis includes urticaria, erythema multiforme, vasculitis, and drug reactions.
Figure 7.6 ▪ Serum Sickness–Like Reaction.
Erythematous maculopapular and urticarial edematous plaques are seen on the thighs (A). (B) in a patient 2 weeks after receiving Bactrim. Fever, arthralgia, and generalized lymphadenopathy (arrow) were other findings. Patient improved with stoppage of Bactrim and supportive care. (Photo contributor: Erin Gilbert, MD, PhD.)
The majority of serum sickness–like reactions are self-limited and resolve in 2 to 3 weeks without sequelae in most cases. Patients can be managed by discontinuation of the offending agent (if still receiving it), antihistamines, and nonsteroidal anti-inflammatory drugs as indicated. A short course of systemic corticosteroids may be used in severe cases of arthralgias and myalgias.
Drugs are the most common cause of serum sickness–like reaction especially the cephalosporin Cefaclor.
Typical cutaneous reactions seen in serum sickness–like reactions are urticarial, morbilliform, or erythema multiforme–like eruptions.
Figure 7.7 ▪ Serum Sickness–Like Reaction.
Morbilliform eruption, swollen, tender knees, elevated ESR, thrombocytopenia, and mild proteinuria were the findings in this patient while receiving cefaclor for 8 days for a sinus infection. Urticarial wheals are the most common type of rash seen with serum sickness–like reaction followed by erythema multiforme–like lesions. (Photo contributor: Binita R. Shah, MD.)
Erythema multiforme (EM) is an acute hypersensitivity reaction that occurs in response to various etiologic agents such as infections (especially Herpes simplex 1 & 2) and rarely drugs. It is self-limited but potentially recurring. Herpes simplex virus is the most common cause; others include mycoplasma, parapoxvirus, and histoplasma. EM is classified into minor and major types, which can be distinguished by the presence or absence of mucosal lesions. EM minor has no or mild mucosal involvement versus EM major, which has severe involvement of one mucosal surface. The classic EM lesion is a target “iris” lesion characterized by 3 zones. The innermost zone consists of dusky purpura, hemorrhagic crust, or blistering; the middle zone, the largest, is pale pink and edematous, whereas the outermost zone is composed of a ring of erythema. Occasionally, atypical targetoid (composed of 2 zones only) papular lesions can be present. The classic distribution of EM lesions is extremities (especially elbow, knees, wrists, and hands), palms and soles, with few truncal lesions. The skin lesions are symmetrically distributed and tend to be fixed for more than 5 days.
Figure 7.8 ▪ Herpes Simplex Virus Infection and Erythema Multiforme.
(A) Primary HSV infection of the lips in a patient who had classic target lesions of EM on the face, palms, and soles. No other mucosal surfaces were involved. (B) Classic target “iris” lesions of EM in a different patient following HSV infection. (Photo contributor: Sharon A. Glick, MD [A] and Reproduced with permission from Shah BR: Atlas of Pediatric Clinical Diagnosis. WB Saunders, Philadelphia, 2000, p. 181. [B])
Figure 7.9 ▪ Herpes Simplex Virus Infection and Erythema Multiforme.
(A) A 15-year-old female with culture proven HSV labialis. Her lips have coalescing vesicles with overlying crusts. (B) Her palm showing classic iris or target lesions. Note the 3 concentric zones with central necrosis surrounded by a zone of edema and a third surrounding ring of erythema. She also had similar lesions on her soles. (Photo contributor: Sharon A. Glick, MD.)
Systemic symptoms are mild or absent. Active herpes simplex lesions or a past history of herpes may be positive. Differential diagnosis of EM includes urticaria (lesions not target-like and transient), urticaria multiforme, drug eruptions, subacute lupus erythematosus, and vasculitis. If diagnosis is unclear, dermatology consult followed by skin biopsy is indicated.
No specific therapy is required for EM minor, which is a self-limited disorder. Acyclovir may be given if active herpes simplex lesions are present. Antihistamines, antipyretics, topical steroids (eg, desonide cream bid) can be given for symptomatic relief. Typical patients with EM minor are usually not severely ill and can be managed as outpatients with follow-up with a primary care provider. Systemic steroids may be considered for severe cases of EM major (eg, prednisone 1-2 mg/kg/d divided once or twice daily for 5-14 days). Prophylactic oral acyclovir can be used for recurrent HSV-induced EM. Prompt treatment of HSV infections in such patients will prevent EM.
EM is a separate entity from Stevens-Johnson syndrome and toxic epidermal necrolysis (TEN). EM does not progress to Stevens-Johnson syndrome or TEN.
EM is referred to as multiforme because the morphology of lesions is so variable.
EM lesions are fixed unlike urticaria, and EM lesions may expand, but they remain on the same body part for 4 to 7 days.
Target or “iris” (with 3 concentric zones) lesions are pathognomonic of EM; however, not all patients with EM will have such lesions. Some of these lesions may be targetoid (with 2 zones) or papular lesions.
EM lesions are distributed mainly on the extremities including palms and soles with either none or only one mucosal surface involvement.
Patients with HSV-associated EM may develop target lesions on the lips associated with lip necrosis that can mimic Stevens-Johnson syndrome.
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are part of a spectrum of hypersensitivity disorders with similar etiologies (most commonly drugs) and can be severe and life-threatening. SJS is the milder form and TEN more severe. In SJS, skin and at least 2 mucosal surfaces are involved. SJS has severe mucosal surface involvement as compared to TEN, whereas epidermal detachment is much more in TEN. Depending on area of epidermal denudation, a 3-grade classification has been proposed: SJS (<10% body surface area [BSA]), overlap SJS-TEN (10%-30% BSA), and TEN (>30% BSA). The most commonly implicated drugs are NSAIDS, antibiotics (penicillins, sulphonamides), and antiepileptics (phenytoin, carbamazepine).
Figure 7.11 ▪ Stevens-Johnson Syndrome.
(A) A 7-year-old girl with this rash while receiving penicillin (eighth day) for pharyngitis. Nikolsky sign was positive with peeling of the epidermis (seen on the face) with minimal pressure. (B) Close-up of erosive stomatitis with hemorrhagic-crusted erosions of lips. Erosions were also present on the buccal mucosa, palate, posterior pharynx, and conjunctiva. (C) Erythematous and purpuric macules are seen on the back with blistering leading to erosions on the buttocks. Less than 10% of the body surface area was involved. (Photo contributor: Binita R. Shah, MD.)
The incubation period is usually 1 to 21 days and prodromal symptoms and mucosal surface involvement may occur before rash and epidermal detachment begins. Clinical features include fever, malaise, upper respiratory tract symptoms, skin pain, and mucocutaneous lesions. The cutaneous lesions are targetoid with dusky purpura, truncal and central in distribution, and with a tendency to coalesce. There may be areas of epidermal detachment and a positive Nikolsky sign. Mucosal surfaces of the eyes, oral cavity, and upper gastrointestinal tract, respiratory tract, and genitals may show blisters, hemorrhagic crusts, painful erosions, and ulcerations.
Diagnosis is usually made clinically. Leukocytosis, elevated ESR, and liver enzyme abnormalities may be present. Frozen-section biopsy of the skin may be performed for confirmation of the diagnosis. Hematoxylin-eosin (H&E) staining of the frozen section of the exfoliating skin will show a full-thickness epidermal necrosis.
Complications include secondary bacterial infection, fluid and electrolyte imbalances, and scarring and strictures of the skin and mucosal surfaces. Ocular sequelae include symblepharon, corneal ulceration, and blindness. The course is protracted over 3 to 6 weeks with a mortality rate ranging from 1% to 5% for SJS and 15% to 35% for TEN.
Hospitalize all patients with suspected diagnosis of SJS or TEN preferably to a burn unit or ICU. Discontinue all drugs introduced within the past month, and do not introduce drugs of a similar class unless the risk of abrupt discontinuation is too high. For example, phenobarbital, carbamazepine, and phenytoin share a common metabolic pathway (cytochrome P450) and may induce a cross-reaction; thus, all 3 drugs are contraindicated after SJS/TEN resulting from any one of them. Obtain urgent dermatology, ophthalmology, urology, and ENT consultations. Supportive care includes management of fluid and electrolytes, pain, thermoregulation, nutritional support, and meticulous skin care (gentle saline soaks and petrolatum gauze to provide barrier over denuded areas). Do not use silver sulfadiazine in patients with sulfonamide-induced SJS or TEN. Provide reverse isolation to prevent secondary bacterial infection. Prophylactic use of systemic antibiotics is not recommended. Systemic corticosteroid use is controversial (risk of increased morbidity and mortality; hence routine use is discouraged). The current and newly recommended therapy is IV IG given as 1 g/kg/d daily for 3 days. It helps to reduce development of new blisters and helps to arrest the progression of the disease. (IV IG should be free of any IgA to prevent hypersensitivity reaction in IgA-deficient individuals.)
Most common etiology for SJS and TEN are drugs, while most common etiology for EM is herpes simplex virus.
In children, SJS is more commonly seen than TEN. Incidence of TEN is more common in human immunodeficiency virus (HIV) patients.
Differential diagnosis of TEN includes staphylococcal scalded skin syndrome (SSSS). TEN is full-thickness epidermal necrosis and denudation, whereas SSSS is a superficial peeling of skin (within the epidermis, below the stratum corneum). Hence, complications are much more grave and severe in TEN.
Both SJS and TEN are potentially life-threatening diseases because of multisystem involvement.
Figure 7.12 ▪ Stevens Johnson Syndrome.
Targetoid lesions with 2 zones consisting of central purpura and outer red/pink zone of erythema and edema on the trunk of a patient following exposure to penicillin. This was followed by evidence of epidermal denudation. (Photo contributor: Eve Lowenstein, MD, PhD.)
Figure 7.13 ▪ Toxic Epidermal Necrolysis.
A 3-year-old boy with TEN (70% BSA involvement) with this rash a week after taking phenobarbital for recurrent febrile seizures. (photographs taken between second and third day of illness). (A) Bilateral eye involvement with mucopurulent discharge. (B) Erosive stomatitis and hemorrhagic crusted erosions of the lips. (C, D). Abrupt onset and worsening within 24 hours with dark necrotic skin peeling off, leaving a raw dermis. (Photo contributor: Binita R. Shah, MD.)
Figure 7.14 ▪ Toxic Epidermal Necrolysis.
(A) Five-year-old girl with this rash (100% BSA involvement) while receiving trimethoprim-sulfamethoxazole (10th day) for a urinary tract infection (photographs taken on seventh day of illness). (A) Extensive involvement of the face with necrotic skin is seen. (B) Close-up of mucosal involvement of the lips showing painful hemorrhagic erosions. (Photo contributor: Binita R. Shah, MD.)
Drug-induced hypersensitivity syndrome (DIHS) is a subset of adverse drug eruptions, which occur 1 to 21 days after starting a new medication, whereas it takes only a few days for the reaction to occur following second exposure to the same class of medication. The most commonly implicated drugs are antibiotics (penicillins, sulfonamides), antiepileptics (phenytoin), NSAIDS, antihypertensives, and anti-HIV medications, though any drug can cause an adverse reaction. Cross-reactivity is common among different drugs of same class of medications. Drug reactions are more common in HIV-positive individuals. Exanthematous (maculopapular or urticarial) reaction is seen most commonly, and has a widespread, bilateral and symmetric distribution that may involve the palms and soles. Fever, malaise, and mild mucosal surface involvement may be the presenting symptoms. In a variant known as drug reaction with eosinophilia and systemic symptoms (DRESS), the exanthematous drug rash is associated with fever, facial edema, and involvement of at least one internal organ (liver commonest) with eosinophilia. The incubation period of DRESS is usually 2 to 6 weeks and it takes weeks to subside, even after drug withdrawal. Another variant is acute generalized exanthematous pustulosis (AGEP), which is an acute eruption characterized by multiple tiny pustules that heal in 4 to 10 days with desquamation. This is considered an adverse eruption to medications or vaccine administration. The closest clinical differential diagnosis is a viral exanthem. Eosinophilia is more common in drug eruption than viral exanthems.
Figure 7.16 ▪ Drug-Induced Hypersensitivity Syndrome.
(A, B) Morbilliform maculopapular drug hypersensitivity reaction seen over the trunk and leg in a child following exposure to azithromycin. The rash improved after stoppage of the drug and supportive management. No mucosa was involved. (Photo contributor: Julie Cantatore, MD.)
The diagnosis is clinical, and a detailed current and previous drug history with time charting is mandatory to pinpoint the offending drug. If clinical suspicion of an adverse drug reaction is high, discontinue the suspected offending drug. Laboratory tests include CBC, liver enzymes, and urinalysis. Hospitalize children with severe skin findings, evidence of systemic involvement, or inability to maintain hydration (eg, during erythrodermic phase). A dermatology consultation would assist in such decisions. Biopsy of the skin reveals a dense infiltrate of the papillary dermis, which is composed mostly of lymphocytes and occasionally of eosinophils. Treatment is mostly supportive and includes skin care (eg, topical steroids to alleviate symptoms), prevention of infection, and treatment of any complications. Oral or IV steroids are sometimes used in patients with severe systemic involvement and in DRESS, to prevent complications.
Figure 7.17 ▪ Drug-Induced Hypersensitivity Syndrome/DRESS.
This child presented with an extensive papular rash occurred 35 days after starting phenytoin for seizure disorder. Papular lesions are seen on both legs (A), and arms (B), close-up shows indurated nature of rash (C). (Photo contributor: Binita R. Shah, MD.)
Figure 7.18 ▪ Drug-Induced Hypersensitivity Syndrome/DRESS.
(A) Patient presented with fever, facial edema, lymphadenopathy, a monomorphous rash all over the body, and elevated liver enzymes requiring hospitalization. He was treated with a slow taper of oral steroids. (B) Close-up of the monomorphous rash. (Photo contributor: Sharon A. Glick, MD.)
Figure 7.19 ▪ Drug-Induced Hypersensitivity Syndrome.
Acute generalized exanthematous pustulosis (AGEP). Patient presented with fever and an acute eruption of multiple sterile pustules all over the face, extremities, and trunk following exposure to an antibiotic 2 weeks prior. The lesions healed with desquamation following stoppage of the antibiotic. (Photo contributor: Sharon A. Glick, MD.)
Figure 7.20 ▪ Drug-Induced Hypersensitivity Syndrome (DIHS) versus Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis.
(A) Mucous membrane involvement in patients with DIHS is either minimal or absent. (B) Extensive mucous membrane involvement is seen in patients with Stevens-Johnson syndrome/toxic epidermal necrolysis. (Photo contributor: Binita R. Shah, MD.)
Figure 7.21 ▪ Drug-Induced Hypersensitivity Syndrome (DIHS) versus Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis.
(A) Absence of necrolysis in spite of very extensive skin involvement is seen in DIHS. (B) Vesicles, bullae, or purpuric lesions and necrolysis are typical findings in Stevens-Johnson Syndrome/toxic epidermal necrolysis. (Photo contributor: Binita R. Shah, MD.)
DIHS is often misdiagnosed as a viral infection. Prompt recognition and discontinuation of the drug is of the utmost importance in preventing or minimizing the severity and duration of internal organ involvement.
AGEP is an acute exanthematous drug eruption, characterized by fever, multiple sterile pustules that subside spontaneously with desquamation. In children, it occurs following a viral exanthem, vaccine administration, or rarely drugs.
Henoch-Schönlein purpura (HSP) is a small vessel vasculitis characterized by palpable purpura, arthritis, gastrointestinal (abdominal pain), and renal manifestations (glomerulonephritis) and seen in children age 2 to 11 years. About 50% of patients have preceding respiratory infection; mainly group A beta hemolytic streptococcal infection. Other implicated pathogens include hepatitis B virus, adenovirus, mycoplasma, herpes simplex virus, parvovirus, and HIV. Certain foods, drugs, exposure to cold weather, and insect bites are other predisposing factors. Palpable purpura on lower extremities bilaterally is the presenting sign, and new lesions may develop in crops. This may be associated with fever, joint swelling and arthralgia, abdominal pain, bloody stools, and hematuria.
Diagnosis is clinical. CBC may show leukocytosis, thrombocytosis, and anemia. ESR may be elevated and serum complement levels depressed. Antistreptolysin antibodies are positive in about 50% of cases. Perform urinalysis (may show gross or microscopic hematuria, proteinuria, white blood cells, and casts), and stool guaiac to screen for renal and gastrointestinal involvement. Use ultrasound to evaluate for intussusception and Doppler flow studies to evaluate scrotal problems. In doubtful cases, skin biopsy helps to confirm leukocytoclastic vasculitis.
Complications include bowel obstruction or perforation, intussusceptions, nephrotic syndrome, azotemia, oliguria, chronic glomerulonephritis, hypertensive encephalopathy, central nervous system (seizures, coma, paresis), and acute scrotum (mimicking acute testicular torsion).
Figure 7.22 ▪ Henoch-Schönlein Purpura (HSP).
(A) A 6-year-old boy with crops of palpable purpura on lower extremities and arthritis. (B) Shown here is sparing of the trunk. Lesions in HSP can also appear on the arms, face, and ears. (C) Close-up of purpura and swollen right ankle. (Photo contributor: Binita R. Shah, MD.)
There is no specific treatment. The majority of cases are self-limiting, and symptoms resolve in a few weeks without permanent residua. Supportive, symptom-directed treatment includes bed rest, bland diet, and NSAIDs for relief of arthritis and fever. Elevation of the scrotum helps scrotal edema. Hospitalize any patient presenting with complications (eg, hypertension, oliguria, intestinal obstruction, or gastrointestinal bleeding). Remove the offending antigen, if identified (eg, drugs). Treat the infection if identified (eg, group A B-hemolytic streptococcus). Systemic corticosteroids are indicated for systemic involvement such as severe arthritis, renal involvement, gastrointestinal tract complications, and acute scrotum or CNS complications. Corticosteroid therapy does not prevent recurrences, which are usually seen in up to 50% of cases within the first few months (milder and more common in patients with nephritis). Long-term morbidity and mortality is attributed almost exclusively to renal disease. Serial urinalyses and follow-up of renal functions are recommended, if the initial tests show any abnormalities.
HSP is the most common cause of nonthrombocytopenic purpura.
The classic finding is palpable purpura seen most prominently on the lower extremities.
Long-term morbidity and mortality is attributed almost exclusively to renal involvement.
Arthritis or gastrointestinal symptoms may precede the appearance of rash by up to 2 weeks.
Testicular involvement occurs in up to 35% of patients, and acute scrotal swelling may present prior to purpura and can mimic acute testicular torsion or incarcerated inguinal hernia.
Seborrheic dermatitis is an inflammatory disorder commonly seen in infancy and adolescence. Affected areas include the scalp, face, retroauricular areas, mid-chest, axillae, groins, and other intertriginous areas where sebaceous glands are prominent. It is characterized by an erythematous, greasy scaly scalp (cradle cap). Lesions may be present in the diaper area including folds (which is spared in atopic dermatitis). Petaloid erythematous noneczematous scaly oval plaques may be present on the trunk, back, and flexures. Secondary monilial infection (due to colonization with Candida albicans) and secondary bacterial infections are common, especially in the diaper area. Peak occurrence in infancy is at 3 months of age and usually starts to resolve around 8 to 12 months of age. Differential diagnosis includes atopic dermatitis, Langerhans cell histiocytosis, and immunodeficiency disorders. Overlap of atopic dermatitis and seborrheic dermatitis is quite common in infants. Lack of response to topical steroids in suspected atopic dermatitis in an infant should raise the suspicion of seborrheic dermatitis.
For infants, minor amounts of scale are easily removed by frequent shampooing with products containing sulfur, salicylic acid (eg, Sebulex shampoo), or ketoconazole shampoo. Warm mineral or olive oil compresses followed by washing several hours later and lifting off the scale with a fine-toothed comb may be helpful for scales that are dense, thick, and adherent. For older children and adolescents, antiseborrheic shampoos containing selenium sulfide (eg, Selsun blue), zinc pyrithione (eg, Head & Shoulders), coal tar (eg, Neutrogena T/Gel), or ketoconazole (eg, Nizoral) can be used intermittently (eg, 2-3 times per week). Instruct the patient/parent to lather the shampoo and let it sit on the scalp for 5 to 10 minutes before rinsing. If there is evidence of inflammation, application of a topical low- to mid-potency corticosteroid solution to the scalp and cream to nonhairy inflamed areas, is indicated. Caution patients that topical steroids should not be used as maintenance therapy. Topical antifungal agents are also effective.
Seborrheic dermatitis is the most common rash in the first few months of life.
Suspect coexisting atopic dermatitis when lesions are weeping and associated with pruritus.
With pronounced localized scaling, seborrheic dermatitis may resemble psoriasis.
Seborrheic dermatitis is one of the most common cutaneous manifestations of AIDS in older children and adolescents, and onset usually occurs before AIDS symptoms.
Seborrheic dermatitis is a self-limiting disorder and does not cause permanent or scarring alopecia of the scalp.
Allergic contact dermatitis results from exposure to a topical allergen by a sensitized individual. Percutaneous absorption of an allergen leads to specific T lymphocytes carrying the immune memory to recognize the antigen as a foreign material. Re-exposure to the same allergen results in proliferation of sensitized T lymphocytes that release inflammatory mediators, leading to a localized eczematous dermatitis. The most common contact allergens include plants (eg, urushiol in poison ivy, poison sumac, poison oak), nickel (eg, jewelry, metal wrist band, snap buttons of trouser jeans), shoe materials (eg, rubber and leather [potassium dichromate used for tanning leather]), thimerosal (a preservative in eye drops and vaccines), fragrances, cosmetics, and topical medications (eg, preparations containing neomycin). Allergic contact dermatitis is seen in children and first exposure to an allergen may occur as early as in infancy.
Diagnosis is based on distribution and morphology of the lesions (eczematous, vesiculation, oozing, and in chronic lesions lichenification) and history of exposure. Sharp demarcation between normal and affected skin, with linearity, suggests allergic contact diagnosis. A patch test, done by a dermatologist (if etiology not apparent), can help with a diagnosis. A positive test shows erythema and papules confined to the test site.
Once allergic contact dermatitis has been diagnosed, identification and elimination of the allergen (eg, removal of nickel jewelry), and avoidance of further exposure is necessary. Antihistamines are used (eg, hydroxyzine) to control the pruritus. Avoid use of topical diphenhydramine, as it is a sensitizer (with prolonged use, the patient may develop sensitization). Topical high- or mid-potency corticosteroid cream applied twice a day for 2 to 3 weeks, with avoidance of allergen, treats the condition. Rarely, systemic steroids may be needed (eg, in cases caused by poison ivy, prednisone 1-2 mg/kg/d tapered over 2 to 3 weeks, helps to control the acute inflammation). For poison ivy, if possible provide/show a picture of the offending plant for patients and family members so they can avoid further exposure. When outdoors, advise using a barrier cream (eg, Ivy Shield), which blocks the resin from touching the skin and washing the exposed area immediately, if accidental exposure occurs. Recurrences are common if the suspected allergen is not eliminated completely; thus all the ingredients (even in the minutest of proportions) in the suspected allergen should be avoided.
Diagnosis is based on the history of exposure and the pattern of the rash (eg, a symmetrical erythematous rash on both ear lobes in a patient wearing nickel earrings).
One of the most common contact allergens in chidren is urushiol, the sensitizing antigen found in poison ivy.
A thorough history is the most important step in management and includes inquiring about animal exposure. Poison ivy dermatitis can result from touching an animal exposed to the plant.
Autosensitization dermatitis (Id eruption) occurs as acute papulovesicular pruritic symmetric eruptions on the trunk, forearms, extensor surfaces, and rarely on the face and is a hypersensitive reaction to acute dermatitis and bacterial or fungal infections.
Koebner phenomenon (isomorphic phenomenon), in which trauma elicits similar lesions, is also seen in an Id eruption. The diagnosis is clinical and treatment of the primary dermatitis is crucial. Open wet compresses, antihistamines, and topical steroids may also help.
Figure 7.32 ▪ Allergic Contact Dermatitis.
(A) Adolescent with recurrence of poison ivy dermatitis seen on face and neck. Premature termination of oral corticosteroids (patient treated for 3 days only), as occurred in this case, may result in rebound dermatitis. In severe cases, it is important to treat with a steroid taper over 2 to 3 weeks. (B) Erythematous linear streaks of urticaria on the abdomen due to spread of urushiol oil. (C) Linear array of vesicles of the fingers. (Photo contributor: Sharon A. Glick, MD.)
Atopic dermatitis (AD) is an eczematous dermatitis manifested as a result of persistent inflammation of the skin. It is often associated with allergic diseases like asthma and allergic rhinitis and manifests as acute, subacute, and chronic dermatitis. Diagnosis is based on classic morphology and distribution of dermatitis depending on the age group. The infantile phase is from 2 months to 2 years, characterized by severe pruritus, oozing, vesiculation, eczematous papules, plaques seen on the face, scalp, extensors of extremities, and trunk. During infancy, the sparing of groin and diaper area helps to differentiate infantile atopic dermatitis from seborrheic dermatitis. The childhood phase lasts from 2 years of age to puberty and is characterized by dry scaly, lichenified pruritic plaques, seen on the antecubital fossae, popliteal fossae, periorbital and perioral areas, wrists, hands, and feet. The adult phase begins at puberty and continues into adulthood and is characterized by chronic pruritic lichenified plaques present on the flexors, neck, face, trunk, hands, and feet. Nummular eczema is a variant of AD characterized by discoid, well-circumscribed, annular plaques, commonly seen on the extremities. Associated features of AD include pityriasis alba, periorbital darkening, ichthyosis vulgaris, white dermographism, keratosis pilaris, and hyperlinear palms. Elevated serum IgE with peripheral eosinophilia may be seen. Secondary bacterial and viral infections are common.
Figure 7.33 ▪ Nickel Contact Dermatitis.
Nickel sulfate found in a belt buckle was responsible for this rash that was treated with steroid cream without success because patient continued to wear belt. Contact dermatitis from nickel snaps on denim and from belt buckles is often mistaken for eczema (like in this patient). This patient’s rash improved only after discontinuation of wearing the belt. (Photo contributor: Binita R. Shah, MD.)
The majority of patients with AD are treated as outpatients. Management consists of establishing realistic parental expectations that AD is a chronic disorder that involves remissions and exacerbations. Goals of therapy are to control the flare-ups, prevent secondary infections, and keep the skin barrier function intact by constant moisturizing. Advise patient to avoid trigger factors like hot water, heat, allergens like dust mites, pollens, molds, foods like eggs and peanuts, materials like wool and fur, exposures to animals (eg, dogs, cats) or items filled with feathers or down (eg, pillows), stress, and infections (eg, Staphylococcus aureus, herpes simplex, dermatophytes). Advice on constant and regular care of the dry and xerotic skin includes daily moisturizing, brief baths or showers in lukewarm water lasting not more than 5 to 10 minutes, use of a mild unscented soap or liquid gentle skin cleanser (eg, Dove fragrance-free soap, Aveeno), patting (don’t rub) the skin dry, leaving some moisture. Moisturizers (eg, Vaseline, Aquaphor) are applied all over the skin, as soon as the child gets out of the bath or shower to trap moisture in the skin. Moisturizers should be applied to the entire body 2 to 3 times a day. Mid- to high-potency topical steroids are used for body areas (except groin, face, axillae). Mild topical steroids are used for face, groins, and axillae but not more than 2 to 3 weeks at a stretch. Topical antibacterial agents (eg, mupirocin) can be used if there is any evidence of excoriations or open wounds. If the infection is severe, oral antibiotics for 7 to 10 days can be used. Topical immunomodulators like pimecrolimus 1% or tacrolimus 0.03% or 0.1% ointment can be used as steroid-sparing agents. Antihistamine (eg, hydroxyzine) is used for control of the severe itch that causes the rash. Patient should be referred to a primary care physician or dermatologist for ongoing care.
Atopic dermatitis is the “itch that rashes.” Pruritus, xerosis, and eczema are prominent features of AD.
Hospitalization is indicated for eczema herpeticum, generalized erythroderma, severe AD with compromised skin barrier causing failure to thrive or severe flare-ups unresponsive to conventional treatment.
Moisturizers form the mainstay of therapy. Topical steroids, antibacterials, and avoidance of trigger factors are the other pillars of the therapy.
Figure 7.40 ▪ Atopic Dermatitis.
Nickel dermatitis. Well-defined hyperpigmented lichenified plaque seen on the waist, below the umbilicus (a classic site for nickel dermatitis), in an atopic patient due to constant contact with nickel in the buttons or belts touching the skin. (Photo contributor: Sharon A. Glick, MD.)
Eczema herpeticum (EH) is a disseminated cutaneous herpes simplex virus (HSV) infection superimposed on a preexisting active skin condition. A likely cause is the impaired skin barrier in active atopic dermatitis, which allows viral particles to incubate and proliferate quickly, leading to severe dissemination. EH is most commonly caused by HSV-1, and less commonly by HSV-2. Though most commonly seen in patients with atopic dermatitis, it can also occur with other primary dermatologic disorders (eg, seborrheic dermatitis, irritant contact dermatitis, pemphigus, burns, ichthyosis vulgaris, skin grafts). A history of contact with a family member with recurrent oral/facial HSV infection is often found. Clinically, monomorphous vesicles, pustules, and erosions may be seen on a preexisting dermatitis. There may be multiple punctate erosions, some coalescing to form larger polycyclic erosions. EH is more commonly seen on the face, neck, and chest areas and can lead to fatality in infants and young children, if not treated promptly. The diagnosis is usually clinical but can be confirmed by direct fluorescent antibody assays, Tzanck smear, viral culture, and viral DNA polymerase chain reaction for HSV. Complications include secondary bacterial infection (Streptococcus pyogenes and S aureus), keratoconjunctivitis, viremia, and scarring.
Figure 7.42 ▪ Eczema Herpeticum.
(A) Acute eruption of multiple erythematous vesiculopapular lesions with central crusting is seen on the right cheek of a young boy with atopic dermatitis. As lesions involve the face and are close to the eye, an urgent ophthalmology consult is indicated to exclude corneal involvement. (B) Erythematous vesiculopapular lesions around the eyes and mouth with crusting are seen in a different infant. (Photo contributors: Falguni Asrani, MD. [A] and Christy Riley, MD [B].)
High index of suspicion for EH in patients presenting with a history of “worsening” atopic dermatitis is an important step necessitating DFA or Tzanck smear (DFA preferred over Tzanck because of superior sensitivity, rapid turnover) and viral culture, if diagnosis is uncertain. Dermatology consultation will be valuable in such cases. Ophthalmology consultation is mandatory for involvement of or near the eyes. Hospitalization of infants and young children with EH is indicated in severe cases to prevent complications with prompt administration of IV acyclovir till lesions crust over. Maintaining hydration and skin care are also important. Bland emollients may be applied to the affected areas. Mild cases of EH can be managed as outpatients with acyclovir given orally with a very close follow-up by a primary care physician or a dermatologist. Antistaphylococcal antibiotics should be given along with acyclovir either IV (severe EH requiring hospitalization) or oral or topical mupirocin may be used with early localized mild cases not requiring hospitalization.
Figure 7.43 ▪ Eczema Herpeticum.
Acute eruption of multiple punctate erosions on the face and neck of an adolescent girl with recalcitrant atopic dermatitis. These punctate erosions also coalesced to form large polycyclic erosions. Viral culture was positive for HSV, type 1. (Photo contributor: Haamid Chamdawala, MD.)
“Punched out” erosions superimposed on a preexisting active dermatitis-like atopic dermatitis are important clues.
Suspect EH when infected-appearing eczema does not respond to appropriate antibiotic therapy; this may indicate HSV infection.
Appropriate acyclovir dosing and skin care is key to prompt recovery from EH.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
