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Several large studies have reported a widely varied incidence of exfoliative dermatitis (ED) ranging from 0.9 to 71.0 per 100,000 outpatients.1–4 A male predominance has been described, with a male-to-female ratio of approximately 2:1 to 4:1. Any age group can be affected, and with most studies excluding children, the average age of disease onset varies from 41 to 61. ED is a rare disease in children, and only little epidemiologic data is available for pediatric populations. One study found 17 patients, recorded over a 6-year period, with a mean age of onset of 3.3 years and a male-to-female ratio of 0.89:1.5 ED occurs in all races.6
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A preexisting dermatosis plays a role in more than one-half of the cases of ED. Psoriasis is the most common underlying skin disease (almost one-fourth of the cases). In a recent study of severe psoriasis, ED was reported in 87 of 160 cases.7
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Establishing the etiology of ED can be challenging since it can be caused by a variety of cutaneous and systemic diseases (Table 23-1). A compilation of 18 published studies1,2,4,6,8–21 from various countries on ED shows that a preexisting dermatosis is the most frequent cause in adults (52% of ED cases; range, 27%–68%) followed by drug hypersensitivity reactions (15%), and cutaneous T-cell lymphoma (CTCL) or Sézary syndrome (5%). No underlying etiology is identified in approximately 20% of ED cases (range, 7%–33%) and these cases are classified as idiopathic.
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