A 47-year-old female consulted for a pruritic eruption consisting of targetoid lesions with a peripheral scaling collarette that appeared five days prior to consultation. The lesions presented a symmetrical distribution on both upper and lower limbs and on the buttocks (Figs. 1a – 1c). Neither a herald patch nor lesions on the trunk was observed. The oral and genital mucosae were intact. Neither fever nor deterioration of the general health was reported. Based on the clinical examination, the most probable diagnosis was atypical erythema multiforme type-like pityriasis rosea.

Figure 1: (a) Symmetrical lesions of pityriasis rosea on both arms (erythema multiforme type-like). (b) Lesions of pityriasis rosea on the posterior surfaces of both lower limbs. (c) Lesions of pityriasis rosea on both buttocks and legs.

Pityriasis rosea is a papulosquamous eruption characterized by papules and plaques with a peripheral scaling and a Christmas tree-like distribution on the trunk preceded by a herald patch in its typical form, while atypical variants have also been described [1]. Herpes 6 and 7 viruses and COVID-19 virus have been implicated in its etiopathogenesis [2]. Pityriasis rosea in both the typical and atypical forms is a self-limiting condition regressing without sequelae.

The final diagnosis was atypical erythema multiforme type-like pityriasis rosea. The differential diagnoses were psoriasis guttate, erythema multiforme, and lichenoid pityriasis.