Papulosquamous Diseases

Abstract

Papulosquamous diseases are characterized by scaling papules and plaques. “Scaling” is synonymous with “squamous” in this regard. This group of diseases traditionally includes psoriasis, parapsoriasis, pityriasis rosea, pityriasis rubra pilaris, lichen planus, tinea corporis, secondary syphilis, mycosis fungoides, and drug eruptions. These diseases represent diverse infectious, proliferative, reactive, and neoplastic conditions.

The papules and plaques may have different shapes and sizes. Papules may be pinpoint, follicular, round, oval, polygonal, or even atrophic but are never square or rectangular. It is a truism of dermatology that “nature abhors straight lines.” Lesions with straight lines suggest extrinsic sources. Papules may be dome-shaped, acuminate (or pointed), ulcerated, verrucoid, telangiectatic, bleeding, oozing, excoriated, or crusted.