A 26 year Old Woman Presents With A Rash That Began As Salmon Colored Patch.

A 26-year-old woman presents with the above rash. She states the rash is minimally pruritic and developed over the last week. She has had some virus-like symptoms and reports the rash began as a large salmon-colored patch on her chest area which later spread all over her trunk and abdomen. The most likely diagnosis is
A) Tinea versicolor
B) Pityriasis rosea
C) Varicella
D) Psoriasis
E) Coccidioidomycosis

The correct answer is
B. (Pityriasis rosea)

Discussion:
Pityriasis rosea is a self-limited, exanthematous skin disease that develops acutely and is characterized by the appearance of slightly inflammatory, oval, papulosquamous lesions on the trunk and proximal areas of the extremities. Pityriasis rosea is largely a disease of older children and young adults. It is more common in women than in men.

Clinical features: A prodrome of headache, malaise, and pharyngitis may occur in a small number of cases, but except for itching, the condition is usually asymptomatic. The eruption commonly begins with a “herald patch”: a single round or oval, sharply demarcated pink or salmon-colored lesion on the chest, neck, or back, 2 to 5 cm in diameter. The lesion soon becomes scaly and begins to clear centrally, leaving the free edge of the scaly lesion directed inward toward the center. A few days or a week or two later, oval lesions similar in appearance to the herald patch, but smaller, appear in crops on the trunk and proximal areas of the extremities. The long axes of these oval lesions tend to be oriented along the lines of cleavage of the skin. This characteristic Christmas-tree pattern is most evident on the back,
where it is emphasized by the oblique direction of the cleavage lines in that location.

Management: Most cases of pityriasis rosea need no treatment other than reassurance and proper patient education. Topical steroids with moderate potency are helpful in the control of itching. They can be applied to the pruritic areas two or three times daily. Topical antipruritic lotions such as prax, pramagel, or sarna may also be helpful.