[Incontinentia pigmenti].

Abstract

Figure 1. Intact and encrusted vesicles in a blaschkoid distribution on the right lower extremity. A n otherwise healthy 2-week-old full-term boy was referred to a dermatology clinic for evaluation of an eruption on his posterior right leg first noted in the newborn nursery. On examination, there were intact and crusted vesicles extending in a linear fashion from the gluteal fold to the plantar foot (Figure 1). A vesicle was unroofed and microscopic examination of its contents revealed abundant eosinophils (Figure 2; available at www.jpeds. com). A clinical diagnosis of incontinentia pigmenti (IP) was rendered. IP is a rare X-linked dominant genodermatosis with a prevalence of approximately 0.7/100 000 live births. It is often identified by a characteristic blaschkoid eruption that progresses through the following morphologic stages over the course of years: (1) erythema and vesicopustules; (2) hyperkeratotic, verrucous papules, and plaques; (3) hyperpigmented patches; and (4) hypopigmented atrophic, alopecic plaques. Although IP is widely considered to be lethal in antenatal males, there have been over 120 reported cases of males with IP. This can be explained by 3 proposedmechanisms: (1) 47XXY karyotype; (2) somatic mosaicism in the common NEMO deletion responsible for 80% of 46 XX IP cases; or (3) other mutations in the NEMO gene conferring a milder phenotype. IP is a multisystem disorder affecting the skin, eyes, hair, central nervous system, and teeth. Upon diagnosis, all patients should undergo complete ophthalmologic examination to evaluate for optic atrophy, retinopathy, and strabismus. Any observed central nervous system anomaly including seizures, developmental delay, and microcephaly should prompt referral to neurology, as these may represent neurologic complications of IP. Further, evaluation by genetics is crucial to facilitate patient understanding of the condition and to discuss genetic testing. For comprehensive care of patients with IP, long-term and close cooperation between dermatologists, pediatricians, neurologists, geneticists, and dentists is critical. n