Abstract
Pediatric skin conditions are variable and can be confusing for practitioners. This chapter covers various topics including tickborne rashes, erysipelas, impetigo, tinea infections, urticaria, burns, abscesses, herpetic infections, scabies, and pityriasis rosea.
Keywords
abscess, burns, erythema migrans, erysipelas, herpes, impetigo, Lyme disease, pityriasis rosea, rash, scabies, tinea, urticaria
1
True or False. Ixodes scapularis is the vector causing all cases of Lyme disease in the United States
False. Ixodes scapularis is the vector transmitting Borrelia burgdorferi , the cause of Lyme disease, in the East, including New England and the eastern mid-Atlantic states as far south as Virginia (≥90% of all cases), as well as the upper midwest. Ixodes pacificus is the vector in the west. Most cases occur between April and October, but cases can occur year-round. In addition to outdoor activities, cases in urban areas and backyards have been reported. Most bites are from nymphs, which are small and hard to identify. The highest incidence of infection in the United States is in children between 5 and 9 years of age and adults 55–59 years of age. The incubation period from tick bite to appearance of erythema migrans (EM) ranges from 1 to 32 days.
2
What are the clinical manifestations associated with the three stages of Lyme disease?
Early localized disease occurs within 3–30 days post exposure to a tick bite. The characteristic lesion is erythema migrans. Early disseminated disease can have multiple EM lesions, or no associated dermatologic findings. Other manifestations include cranial nerve palsies, especially of cranial nerve VII (Bell palsy), lymphocytic meningitis, polyradiculitis, ophthalmic changes, and nonspecific systemic symptoms. Carditis and heart block can occur but are less common in children. Late disease (months to years postexposure) is rare in previously treated patients. In children, this commonly presents as a pauciarticular arthritis affecting the large joints, especially the knees. Neurologic complications, including encephalitis, are rare.
3
Is the rash of erythema migrans alone sufficient for initiating treatment of Lyme disease?
Yes. EM is the most common clinical manifestation of early localized Lyme disease, and the most common manifestation in children. Appearing 7–14 days after tick detachment, and initially as a painless red macule or papule, it expands into a nonpruritic erythematous annular lesion, occasionally with central clearing and a diameter ≥5 cm ( Fig. 23.1 ). The center may appear necrotic or vesicular. It may be confused with hypersensitivity reactions, which occur while the tick is attached or within 48 hours of detachment, are ≤5 cm in diameter, and disappear in 1–2 days. Associated symptoms may be present, including fever, headache, myalgias, and arthralgias. Treatment prevents progression to the early disseminated and late stages of Lyme disease.
4
What is southern tick-associated rash illness?
Southern tick-associated rash illness (STARI), associated with an EM-like rash and nonspecific symptoms, has been reported in the south central and southeastern United States. The bite of the tick Amblyomma americanum is the cause but does not transmit B. burgdorferi . This illness has not been associated with any of the disseminated complications of Lyme disease. Its etiology and treatment are unknown. When evaluating a patient with an EM rash for Lyme disease, consideration must be given to whether the patient was in an endemic area.
5
What diagnostic serologic testing is available for Lyme disease?
Recognition of Lyme disease rests primarily on recognition of clinical illness in patients who have been in an endemic area; testing for nonspecific symptoms is discouraged. Early localized disease is rarely seropositive. Standard testing is done by two-tiered assay: a sensitive, but not specific, enzyme-linked immunosorbent assay (ELISA or EIA) or immunofluorescent antibody (IFA), and the Western immunoblot. Positive or equivocal results for ELISA, EIA, or IFA necessitate further testing with the Western immunoblot, as false-positive results can occur from cross-reactivity with spirochetal, viral, and autoimmune diseases. The presence of two IgM bands or five IgG bands on the Western immunoblot is a positive result.
6
What is the first-line antibiotic therapy for erythema migrans in pediatric patients with early localized disease?
First-line therapy for the treatment of EM in pediatric patients is amoxicillin, or cefuroxime axetil in those with a penicillin allergy. Doxycycline is recommended for adults and children over 8 years of age but should be avoided in pregnant or lactating patients. Macrolides are not recommended as first-line therapy but may be used if the patient is unable to take the approved drug regimens. Coinfection with other tickborne illnesses should be considered in patients who present with severe initial symptoms; have high fever for more than 48 hours despite an appropriate medication regimen; have unexplained leukopenia, anemia, or thrombocytopenia; or who show no improvement or worsening symptoms.
7
True or False. Successful tick removal involves complete removal of the mouthparts
True. Ticks should be promptly removed in order to decrease the transmission of disease. Removal should be attempted with the use of fine-tipped tweezers, grasping the tick where the mouth parts attach to the skin. Hands should be protected by tissue or gloves. Steady outward pressure should be applied, with care not to twist, crush, or squeeze the tick body. If the mouthparts become detached and stay embedded in the skin and cannot be easily removed, only topical disinfection is required. Attempted removal of embedded mouthparts can cause local tissue damage and have no effect on the risk of contracting Lyme disease. Cleaning the area, hands, and instruments with rubbing alcohol, iodine scrub, or soap and water is recommended.
8
Can tick bites be prevented?
In addition to avoiding tick-infested areas, use of protective clothing, and close inspection for ticks on both humans and pets, tick and insect repellants are recommended for pediatric use. Permethrin-treated clothing is approved for all ages and for pregnant women; it may also be sprayed on clothes but not directly on skin. DEET is approved for use in children over 2 months of age and in formulations containing no more than a 30% concentration. It should not be sprayed on objects that young children might chew or suck. Neurologic complications are rare. Picaridin, the plant-based oil of eucalyptus, provides protection similar to DEET and can be used in patients ages 3 years and older.
9
Should chemoprophylaxis be provided to patients after sustaining a tick bite?
Because the risk of contracting Lyme disease after tick bite is ≤3% in highly endemic areas, routine use of chemoprophylaxis or serologic testing is not recommended. The risk increases after engorgement, especially if attachment is beyond 36 hours. A single dose of doxycycline in older children and adults may be used if all the following requirements are met: the tick has been attached for more than 36 hours and can be identified as I. scapularis , prophylaxis can be started within 72 hours of tick removal, local rate of infection is ≥20%, and the use of doxycycline is not contraindicated. Amoxicillin prophylaxis has not been well studied. Prophylaxis in children less than 8 years of age is not recommended. Children should only receive therapy if symptoms develop.
10
Is follow-up necessary after tick removal and/or administration of antibiotic prophylaxis?
Yes. Close monitoring for signs or symptoms of Lyme disease for up to 30 days is recommended. Medical attention should be sought if a skin lesion or viral-like illness occurs within 1 month of tick removal.
11
What is erysipelas?
Erysipelas is a skin infection involving the upper dermis and surrounding lymphatics. The affected skin is erythematous and indurated with well-demarcated raised borders and is tender to palpation ( Fig. 23.2 ). The skin may have a peau d’orange, or orange peel, appearance. The most common sites affected are the lower extremities, with athlete’s foot a common preceding condition.
15
What is the most common cause of the pictured skin lesion ( Fig. 23.3 )?
The pictured lesion ( Fig. 23.3 ) is impetigo. The nonbullous type is primarily caused by S. aureus and Streptococcus pyogenes . S. aureus accounts for roughly 80% of cases, GAS 10%, and other bacteria 10%. The bullous type is caused by S. aureus . Impetigo is highly contagious and is the most common bacterial skin infection in children.
16
How does impetigo usually present clinically?
It is most common in ages 2–5 years. Nonbullous impetigo begins as erythematous papules, which evolve into vesicles and pustules. These vesicles and pustules rupture to produce a “honey crust” on an erythematous base, primarily on the face or areas of irritation. Bullous-type impetigo is most commonly seen in neonates and infants. Lesions usually occur on intact skin in the intertriginous areas, though they can be seen anywhere on the body. The bullae are small (<3 cm), thin-walled, flaccid lesions containing a clear-to-yellowish fluid ( Fig. 23.4 ). The lesions tend to rupture easily within 1–3 days, leaving behind a collarette scale on an erythematous base or multiple concentric rings, resembling onion slices.
18
What is the initial treatment of impetigo?
Impetigo lesions will usually resolve on their own; however, treatment is recommended to decrease transmission, improve cosmetic appearance, and relieve discomfort. Topical treatment with mupirocin is the preferred method for patients with limited disease for both bullous and nonbullous impetigo. Patients with more extensive disease or who are immunocompromised should also be treated with oral antibiotics. Dicloxacillin and cephalexin are first-line antibiotics, unless methicillin-resistant S. aureus (MRSA) is suspected or confirmed, in which case clindamycin or trimethoprim-sulfamethoxazole is recommended.
19
How do the skin lesions in tinea corporis (body) or tinea pedis (foot) present?
Tinea corporis, more commonly known as “ringworm,” lesions usually begin as pruritic, round (ovoid or circular), erythematous, scaling patches. These lesions spread centrifugally with central clearing and a raised scaling border. There may be clusters of lesions that coalesce. Pustules may be present around the edge of the lesion. Tinea pedis, commonly called athlete’s foot, can present in several ways. Interdigital lesions cause pruritic erythematous erosions or scaling in between the toes; hyperkeratotic lesions present with diffuse hyperkeratotic lesions on soles, medial, and lateral surfaces of the foot. There may be vesicular or bullous lesions as well.
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