Erythematous eruption with linear vesciculation and eosinophilia at birth

We report the case of a patient, first-born to non consanguineous parents, with a negative family history for genetic diseases. Pregnancy was complicated by maternal hypertension and diabetes. The proposita was delivered at 40 weeks of gestation by caesarean section; auxological parameters were at the 50 th percentile. During the first month of life the physical examination showed erythematous eruption with linear vesciculation, and leukocytosis with eosinophilia. During the following months, skin hyperpigmentation appeared with a linear distribution over the limbs and trunk, along Blaschko's lines. The results of the skin biopsy and the presence of a deletion in the NEMO gene confirmed the diagnosis of Incontinentia pigmenti. IP is a genodermatosis that segregates as an X-linked dominant disorder and is usually lethal prenatally in males. In affected females it causes highly variable abnormalities of the skin, hair, nails, teeth, eyes, and central nervous system. Cells expressing the mutated X chromosome are eliminated progressively during the years, thus explaining the variability of the clinical manifestations.