Dermoscopy of pityriasis lichenoides et varioliformis acuta

A 33-year-old woman and a 35-year old man presented with a 3- and 4-week history of multiple (20) diffuse rythematous papules. Some lesions were covered by necrotic crusts. Dermoscopicexamination revealed papules with a central whitish patch and crusted lesions with an amorphous brownish structure. Both types of lesion were surrounded by a well-defined ring of pinpoint and/or linear vascular structures with a targetoid appearance. At higher magnification, the ring of vascular structures appeared dilated and convoluted, with some of them showing a glomerular pattern or linear arrangement and nonblanchable reddish globuleswere observed in all fields. Histopathologic analysis confirmed the clinical diagnosis of pityriasis lichenoides et varioliformis acuta in both patients. The vascular pattern seen by dermoscopy correlates with the presence of dilation and engorgement of blood vessels and microhemorrhages in the papillary dermis. In ourexperience, the dermoscopic appearance is indicative ofpityriasis lichenoides et varioliformis acuta, which helps in the differential diagnosis of other clinically similar diseases (eg, guttate psoriasis, lichen planus, pityriasis rosea,and chickenpox).