Pityriasis Rosea: Diagnosis and Treatment.

Pityriasis rosea is a common self-limiting rash that usually starts with a herald patch on the trunk and progresses along the Langer lines to a generalized rash over the trunk and limbs. The diagnosis is based on clinical and physical examination findings. The herald patch is an erythematous lesion with an elevated border and depressed center. The generalized rash usually presents two weeks after the herald patch. Patients can develop general malaise, fatigue, nausea, headaches, joint pain, enlarged lymph nodes, fever, and sore throat before or during the course of the rash. The differential diagnosis includes secondary syphilis, seborrheic dermatitis, nummular eczema, pityriasis lichenoides chronica, tinea corporis, viral exanthems, lichen planus, and pityriasis rosea-like eruption associated with certain medications. Treatment is aimed at controlling symptoms and consists of corticosteroids or antihistamines. In some cases, acyclovir can be used to treat symptoms and reduce the length of disease. Ultraviolet phototherapy can also be considered for severe cases. Pityriasis rosea during pregnancy has been linked to spontaneous abortions.