What is lipoid proteinosis?

Lipoid proteinosis, also known as hyalinosis cutis et mucosae and Urbach-Wiethe disease, is a rare autosomal recessive genodermatosis in which skin and mucous membranes are infiltrated with a hyaline scleroprotein. The presenting symptom, hoarseness, develops in infancy due to involvement of the vocal cords with hyaline deposits. Bullae, pustules, and crusts, followed by acneiform scars, are seen on the face and extremities. Waxy papules develop along the eyelids, producing a characteristic “string of beads” appearance. Later, verrucous plaques occur on the elbows and knees. Lipoid proteinosis is caused by loss-of-function mutations in the extracellular matrix protein 1 gene (ECM1).

Bahhady R, Abbas O, Ghosn S, et al: Erosions and scars over the face, trunk, and extremities, Pediatr Dermatol 26:91–92, 2009.