Scabies While scabies in older children and adults most commonly presents as numerous ill-defined scaling, erythematous papules, interdigital scaling, and lesions in folds such as the umbilicus, groin, and axillae, infants and very young children can have vesiculobullous lesions on the palms ( Fig 67.1 ), soles, head, and face It is important not to be misled by this distribution and appearance Occasionally, the lesions can be nodular and often involve the genitals and axillae in young children Generally, the parents or other close family contact are also affected and exhibit the typical appearance and pruritus of this disorder First-line therapy for scabies includes permethrin cream (from the head down in infants age >2 months and older, neck down in older children and adults) applied twice, week apart, and washing all fomites in hot water followed by drying on high heat Fomites not amenable to washing may be dry-cleaned or placed in an airtight bag for several days All close contacts should be treated Ivermectin has also been used successfully Acropustulosis of Infancy The appearance of pruritic vesicopustules in infants and young children on the palms and soles ( Fig 67.2 ) may also suggest acropustulosis of infancy Vesicles often involve the lateral aspects of the fingers, palms, and soles This condition may be misdiagnosed as dyshidrotic eczema and is similarly pruritic Some speculate a relationship with antecedent scabies infestation in a subset of patients and may refer to this phenomenon as postscabetic pustulosis in this setting Cyclic eruptions occur every to weeks, lasting to 10 days Spontaneous disappearance occurs at to years of age Treatment with topical steroids may moderate some of the pruritus For a complete differential of acute vesiculobullous eruptions involving the palms and soles, see Table 67.1 MASTOCYTOSIS Cutaneous mast cell disease (mastocytosis or urticaria pigmentosa) may cause blistering in young children and may be associated with activating c-KIT mutations Red-brown lesions ( Fig 67.3A ) that blister after stroking or trauma (Darier sign) indicate the release of histamine from mast cells ( Fig 67.3B ) This collection may be isolated (mastocytoma) or generalized (urticaria pigmentosa or bullous mastocytosis) In addition to stroking, other triggers include mast cell destabilizers such as nonsteroidal anti-inflammatory drugs (NSAIDs), polymyxin B, some anesthetic medications (both topical and systemic), venom from bees or wasps, and narcotics Additionally, extreme temperatures or sudden changes in