Incontinentia pigmenti: pigmentary changes independent of incontinence.

Incontinentia pigmenti is characterized by swirled hyperpigmentation associated with incontinence of pigment. A different pattern may be seen on the legs with light-colored atrophic scarred areas admixed with patches of normal but darker skin. Histologic examination confirms that the darker skin is normal without incontinence of pigment, while the light-colored skin lacks melanocytes and appendages but has dermal fibrosis.