Phthiriasis palpebrarum in a child

A 6-year-old boy presented with persistent erythema and pruritus of the eyelids (Panel A), which had been previously diagnosed as atopic dermatitis and unsuccessfully treated with topical glucocorticoids and systemic antihistamines for 2 weeks. Dermatoscopy showed several crab lice (Phthirus pubis) on the eyelashes along with their ovoid nits (Panel B and Video). A diagnosis of phthiriasis palpebrarum was made; the patient was treated with topical 5% yellow mercuric oxide ointment four times daily for 2 weeks, and the symptoms resolved completely. The eyelashes represent a common area of infestation by P. pubis in children, because of the lack of terminal hairs in other body regions. The lice are generally spread by close contact with infected adults. Phthiriasis palpebrarum is often difficult to identify because of the deep burrowing of the lice in the lid margin, and it is often misdiagnosed as atopic dermatitis or allergic conjunctivitis.