This is the mildest and most common form of ichthyosis, with an incidence in school-aged children as high as 1:250. It is inherited as an autosomal dominant trait and is present in a significant percentage of individuals with atopic dermatitis. It is not present at birth. The clinical appearance of this ichthyosis varies, depending on location. Figure 12-1 illustrates the fine, bran-like scaling on the upper chest. On the anterior lower leg, there are often larger, plate-like scales that resemble the skin of a fish (Fig. 12-2). Facial involvement is usually minimal, and flexural areas are typically spared. Children with ichthyosis vulgaris are likely to have increased skin markings on the palms and soles and a high incidence of keratosis pilaris (see Figs. 8-46–8-48). Ichthyosis vulgaris tends to worsen in winter when there is less sweating and lower humidity.
This figure illustrates the fine scaling of ichthyosis vulgaris and the conspicuous sparing of the flexures. Treatment of ichthyosis vulgaris entails the use of emollients and creams and ointments containing urea, lactic acid, and other alpha-hydroxy acids. Excessive bathing and the use of alkaline soaps should be avoided. The exacerbation that frequently occurs in winter months can be lessened if a humidifier is used in the child's room.
This condition is a rare, chronic, and often severe genodermatosis that is inherited in an autosomal dominant fashion. The appearance of bullous ichthyosis in the newborn is illustrated in Fig. 12-4. Typically, there are large areas of denuded skin, and sometimes there are intact blisters. The differentiation from epidermolysis bullosa can usually be made by positive family history, the presence of subtle areas of hyperkeratosis, and, most important, the characteristic skin biopsy. The genetic defect lies in mutations in genes encoding keratins 1 and 10. Treatment in the newborn period should focus on gentle handling to avoid new blister formation, the maintenance of fluid and electrolyte balance, and the prevention of bacterial superinfection.
Over time, the generalized blistering resolves, and widespread areas of thick hyperkeratosis and scale develop. In Fig. 12-5, there is a mixed picture; focal erosions are present on the arms and abdomen, and there are areas of thick, discolored, furrowed hyperkeratosis. Note the predilection, which is not seen in ichthyosis vulgaris, for the antecubital fossae and intertriginous spaces. Figure 12-6 shows the process in typical areas: the palms, wrists, and knees. For some patients, severe involvement of the palms and soles creates a particular disability. Figure 12-7 shows bullous ...