Pityriasis Rosea

Pityriasis rosea (PR) is a relatively common, benign rash, occurring mostly in individuals between the ages of 10-35 years. Some reports demonstrate a prevalence of PR during the spring and fall months, suggesting a possible infectious (viral) cause. An upper respiratory tract infection may precede the onset of PR in some cases. The rash of PR, however, is not contagious.

Presentation:

In a large percentage of cases, PR begins with the herald patch, an oval, mildly inflamed (salmon-colored) patch with peripheral scale, usually found on the torso (i.e. under the breast). The herald patch is followed a few days to weeks later by a generalized eruption of oval, scaly, salmon-colored lesions distributed over the chest, abdomen, back, arms, and thighs. Lesions may adopt a ‘Christmas tree’ or ‘fir tree’ pattern on the back.

Occasionally, PR may affect the face, armpits, groin, palms, soles, and even inside the mouth. PR may be mildy to moderately itchy and usually lasts anywhere from five to eight weeks before resolving spontaneously. Other conditions which may present similarly include seborrheic dermatitis, ‘ring worm,’ syphilis, drug rash, viral eruptions, and psoriasis.

Treatment:
Since PR is self-limited, treatment options are focused around moisturization and relief of itching (i.e. topical corticosteroids). More extensive and prolonged cases may respond well to ultraviolet light therapy. Other reports have suggested the use of oral antibacterial and antiviral agents, but extensive research regarding these therapies has not been performed.

References:
Chuh A, Lee A, Zawar V et al. Pityriasis rosea-An update. Indian J Dermatol Venereol Leprol 2005;71:311-5.
James WD, Berger TG, and Elston DM. “Pityriasis Rosea, Pityriasis Rubra Pilaris, and Other Papulosquamous and Hyperkeratotic Diseases.” Andrews’ Diseases of the Skin. Tenth Ed. Saunders:Canada, 2006, 207-216.
Stulberg DL and Wolfrey J. Pityriasis rosea. Am Fam Physician 2004;69:87-91.

Matthew Smetanick, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital
Philadelphia, Pennsylvannia.