This benign but frequently annoying eruption is most commonly seen in the active duty age group.  This condition is frequently in the primary care setting.  A serologic test for syphilis or RPR (rapid plasma reagin) is absolutely mandatory to exclude the diagnosis of secondary syphilis.

A truncal or proximal extremity slightly red, scaly 2-6 cm "herald patch" is not always seen or appreciated.  The generalized eruption begins a few days to a couple of weeks later.  Sometimes there is an antecedent history of a flu like illness.  The individual lesions are 1-2 cm macules or patches, ovoid and have a peripheral "collarette" of scale.

The "fir tree" pattern of distribution on the trunk is characteristic in fair skinned patients.  In darker skin, the lesions may be more papular and concentrated on the skin of the infra axillary, upper medial thigh, and waistline.  The presence of palm or sole lesions is quite unusual and should prompt the search for another diagnosis.

The eruption usually lasts 6-8 weeks.  Many cases are asymptomatic or produce little morbidity.  Patients frequently require only reassurance.  The majority of these patients can be returned to full duty.

Some medications produce a pityriasis-like drug eruption.  The most relevant drugs used by the active duty population are captopril, barbiturates, and metronidazole.

Treatment with topical antipruritic lotions, emollients, and conventional oral antihistamines should be considered in pityriasis rosea patients with substantial pruritus.

Written and revised by CAPT Dennis A. Vidmar, MC, USN, Department of Military and Emergency Medicine, and Department of Dermatology, Uniformed Services University of the Health Sciences, Bethesda, MD (1999).

Additional images provided by CAPT Vidmar in June, 2000, subsequent to the initial publication of this manual.