Incontinentia pigmenti: variable disease expression within an affected family.

We report a florid case of incontinentia pigmenti in a neonate in which linear vesiculobullous, verrucous and pigmented lesions were present simultaneously at birth. Histology of a vesiculobullous lesion showed vesiculation with numerous eosinophils in the epidermis, and a sparse infiltrate in the dermis with pigmentary incontinence. The mother of our patient described a streaky linear rash on her legs during her own childhood which resolved spontaneously, in addition to partial anodontia, suggesting that she too has the disease, although previously undiagnosed. This emphasises the variable disease expression and the importance of recognising this condition so that patients can be followed up with regard to complications, and genetic counselling can be offered. The issue of prenatal diagnosis is discussed.