Photo Rounds

Marks on lower leg

A 27-year-old woman presented to her family physician (FP) with 2 marks on her lower leg that had appeared a month earlier. She denied any pain or itching and did not have a clue as to the cause of this new rash. The patient was otherwise healthy and was not taking any medications. She had recently competed in a triathlon, but believed the rash started before the competition.

What’s your diagnosis?


 

Marks on lower leg

The FP suspected that this was lichen aureus (a type of capillaritis that causes a pigmented purpuric dermatosis). Capillaritis is characterized by extravasation of erythrocytes in the skin with marked hemosiderin deposition. It is not palpable. Lichen aureus is a localized and often well circumscribed pigmented purpuric dermatosis that is seen in younger patients. It often occurs on the leg(s) but can be seen on other parts of the body.

Dermoscopy can help to visualize the red or pink dots with a brown background that represent inflamed capillaries with surrounding hemosiderin deposits.

In this case, the FP used his dermatoscope and could see pink dots with a brown background. He explained that this was sufficient to make the diagnosis of lichen aureus but gave the patient a choice to get a biopsy to confirm the clinical impression. The patient preferred to avoid the biopsy and accepted the diagnosis.

There is no proven beneficial therapy for lichen aureus or other types of capillaritis. Fortunately, it is benign and carries no associated health risks. The FP offered triamcinolone cream 0.1% to be applied once to twice daily, but did not promise that it would make the spots go away. The patient wanted to try something, so she accepted the prescription. No follow-up appointment was needed, but the FP did let the patient know that if the condition worsened, further evaluation, including a biopsy, could be performed in the future. The patient was seen a year later for a well woman exam and stated that the rash resolved about 6 months after she’d sought treatment for it.

Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Mayeaux EJ, Usatine, R, Martin N, et al. Vasculitis. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. Color Atlas and Synopsis of Family Medicine. 3rd ed. New York, NY: McGraw-Hill; 2019:1169-1173.

To learn more about the newest 3rd edition of the Color Atlas and Synopsis of Family Medicine, see: https://www.amazon.com/Color-Atlas-Synopsis-Family-Medicine/dp/1259862046/

You can get the 3rd edition of the Color Atlas and Synopsis of Family Medicine as an app by clicking on this link: https://usatinemedia.com/app/color-atlas-of-family-medicine/

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