Derm Dx: An asymptomatic rash on the lower extremities

Pigmented purpuric dermatosis is a benign skin condition of unknown etiology. Patients typically present with petechiae or red-brown macules of the lower extremities, at times associated with pruritus. There are several variants of pigmented purpuric dermatoses, the most common of...

Submit your diagnosis to see full explanation.

Pigmented purpuric dermatosis is a benign skin condition of unknown etiology. Patients typically present with petechiae or red-brown macules of the lower extremities, at times associated with pruritus. There are several variants of pigmented purpuric dermatoses, the most common of which is Schamberg disease. Other types included in this group are purpura annularis telangiectodes (Majocchi disease), Gougerot-Blum disease, lichen aureus, eczematoid-like (itching) purpura, and granulomatous purpura.^1,2 Although the etiology is unknown, many cases are associated with hypertension, diabetes, venous stasis, and pregnancy. This condition can affect any age or race; and it is seen more commonly in men.³ Histopathology reveals perivascular lymphocytic infiltration, extravasation of red blood cells, and hemosiderin deposition.

The use of topical corticosteroids may help alleviate pruritus and decrease the duration of the rash. In younger patients, the rash often resolves spontaneously without treatment.⁴

Rebecca Geiger, PA-C, is a physician assistant on staff at the DermDox Dermatology Center in Hazleton, Pennsylvania. Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College in Scranton, Pennsylvania, and an adjunct assistant professor of dermatology at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.

References

1. Newton RC, Raimer SS. Pigmented purpuric eruptions. Dermatol Clin. 1985;3:165-169.
2. Allan A, Altman DA, Su W. Granulomatous pigmented purpuric dermatosis. Cutis. 2017;100:256-258.
3. Sharma L, Gupta S. Clinicoepidemiological study of pigmented purpuric dermatoses. Indian Dermatol Online J. 2012;3:17-20.
4. Coulombe J, Jean SE, Hatami A, et al. Pigmented purpuric dermatosis: clinicopathologic characterization in a pediatric series. Pediatr Dermatol. 2015;32:358-362.