Pityriasis lichenoides chronica.

A 19-year-old woman presented with a five-year history of guttate macules and yellow to skin-colored papules with collarette of fine scale on the trunk and the upper and lower extremities. Guttate pityriasis lichenoides chronica is an uncommon presentation of this T-cell-mediated disease. It is of unknown etiology; however, an infectious agent has been suspected. It is considered in a spectrum with pityriasis lichenoides et varioloformis acuta and rarely mycosis fungoides and CD30 lymphomas. Improvement has been shown after treatment with oral tetracyclines, ultraviolet B and UVA1 phototherapy, and PUVA photochemotherapy.