Cutaneous lesions can be the first clinical sign of a serious systemic illness. It is important to recognize and treat these illnesses early. Life-threatening dermatoses can be grouped into 3 distinct categories: erythrodermas (diffuse red rashes), vesiculobullous lesions, and hemorrhagic lesions.
Staphylococcal scalded skin syndrome (SSSS) is an exotoxin-producing Staphylococcal infection that causes shedding of the superficial layer of the epidermis. SSSS is most common in children and neonates; 98% of patients are <6 years of age.
Toxic shock syndrome (TSS) causes a diffuse red macular rash associated with fever, hypotension, and malfunction of at least 3 organ systems. It was originally diagnosed in menstruating women using vaginal tampons, but can also be seen in patients with surgical wounds and nasal packings. Incidence is about 10–20 cases per 100,000 persons. TSS is most often caused by a variant of Staphylococcus aureus, which produces the exotoxin TSST-1, which mediates the clinical effects. Streptococcus pyogenes may more rarely cause a similar syndrome.
Kawasaki disease is thought to be an immunologic disorder triggered by infection or toxin, leading to a generalized vasculitis. It causes nearly 3,000 hospital admissions annually and usually appears in children <9 years of age, with a peak incidence in children 18–24 months of age. Epidemics occur primarily in the late winter and early spring. Approximately 20% of patients develop cardiovascular complications, and the most common cause of death is myocardial infarction secondary to coronary artery aneurysm, which can develop 2–8 weeks after fever.
Erythema multiforme (EM), as the name implies, presents with many simultaneous types of skin lesions, including macules, papules, and bullae. EM accounts for as many as 1% of dermatologic outpatient visits and is more common in spring and fall. The etiology is a hypersensitivity reaction precipitated by medications, infections, sarcoidosis, collagen vascular diseases, or malignancies. About 50% of cases are idiopathic.
Stevens-Johnson syndrome (SJS) is a more severe form of EM that involves ≥2 mucosal surfaces such as eyes, lips, mouth, urogenital area, or anus. SJS can progress to toxic epidermal necrolysis (TEN), with large bullae and sloughing of the epidermis in sheets. Frequency is up to 6 cases per 1 million persons annually. The etiology is similar to EM, but medications are more commonly associated with SJS.
TEN is the most severe end of the EM spectrum, with TEN affecting >30% of the body surface area. There is approximately 1 case per 1 million persons annually, with adults most commonly affected. TEN desquamates the entire thickness of the epidermis; therefore, mortality rates are 30–40% from hypovolemia and infection. TEN is thought to be provoked by drugs such as phenytoin, sulfas, penicillins, and nonsteroidal anti-inflammatory drugs. Onset is usually within the first 8 weeks of therapy.
Pemphigus vulgaris (PV) is characterized by flaccid bullae that begin in the mouth and spread to involve the skin. Frequency is approximately 3 cases per 100,000 persons. Peak age of onset is 50–60 years. The etiology is an autoimmune blistering reaction characterized by autoantibodies directed against keratinocyte cell surfaces; some cases are drug-induced. Bullous pemphigoid (BP) is a similar autoimmune blistering disease, but it usually only affects the elderly. Unlike PV, the bullae of BP are tense rather than flaccid, and oral involvement is uncommon.
Patients with disseminated gonococcal infection (DGI) are usually young, sexually active females with fever, skin lesions, arthritis, arthralgias, or migratory tenosynovitis. DGI occurs after approximately 1% of gonococcal genital infections. Certain subtypes of Neisseria gonorrhoeae are more likely to lead to disseminated infection.
Another Neisseria species, Neisseria meningitidis, can cause meningococcemia. Cutaneous manifestations are part of a hemorrhagic cascade resulting from systemic sepsis. The frequency is approximately 2 cases per 100,000 persons annually, although sporadic outbreaks with higher prevalence occur frequently. The mortality rate varies between 10% and 50%, depending on the severity of the systemic infection.
