Perplexing Dermatosis of Legs

Abstract: 33 year-old man with perplexing rash on legs and feet
Presented by Natasha Karishev and Dave Elpern

HPI: This 33-year old man was seen at the FMI on April 11, 2008. He has noticed an asymptomatic eruption on legs and feet for the past few months. He had Graves Disease treated over ten years ago and now is hypothyroid. In addition, he suffers with hypertension and bipolar disorder. His medications include: HCTZ , Depakote, Levothyroxine, Imipramine, Zolpidem, Caduet ((Amlodipine/Atorvastatin)

O/E: Both lower legs are covered with orange-brown, some rust-colored, speckled, cayenne pepper–like discoloration. Spared area under socks. The “Cayenne Pepper-Like” spots are punctate areas of hemorrhage. The patient has exophthalmos, a residual effect of his past Grave’s disease.

Photos: Click on image to enlarge



Diagnosis: Pigmented Purpuric Dermatosis: Subtype: Schamberg Disease

Reason Presented: As a teaching opportunity re: an easily recognized entity that can be misdiagnosed if not known about. This is what is called “A Dermatologic Vignette.”

Discussion: From eMedicine: “The pigmented purpuric dermatoses are a group of chronic diseases of mostly unknown etiology that have a very distinctive clinical appearance. They are characterized by extravasation of erythrocytes in the skin with marked hemosiderin deposition. The etiology is unknown. Venous hypertension, exercise, and gravitational dependency are important cofactors that appear to influence disease presentation. No medical intervention is of proven benefit for the treatment of the pigmented purpuric dermatoses.
* If pruritic use topical corticosteroids and antihistamines.
* Associated venous stasis should be treated by compression stockings.
* Prolonged leg dependency should be avoided.”

In the present case, it is likely that his drugs are playing a role. These may lead to venous hypertension and resulting leakage of rbc. There are old reports of HCTZ causing PPD. The clear areas under his socks indicate that compression stockings may be the best approach here. It is thought that PPDs are caused by capillaritis which leads to leaky vessels. The extravasated RBCs are red (Cayenne Pepper Spots) and when these are reabsorbed they leave hemosiderin behing (the golden brown rusty color)

Reference: The chapter on PPD in eMedicine is an adequate introduction: