This 58-year-old man presented for the sudden onset of an asymptomatic but dramatic change in color of a lesion that had been on his forearm for several months. There was no history of trauma. He had taken daily low-dose aspirin for years, and he had no bruising elsewhere. There had been no change in the patient’s medications.
This patient had a collision of at least 2 of the diagnoses listed above. He had a preexisting benign lichenoid keratosis, which typically develop on sun-exposed areas. This makes the anatomic site susceptible to actinic purpura (also called Bateman purpura), a dermatoheliosis caused by chronic sun exposure that results in easy bruising confined to sun-exposed surfaces due to loss of collagen integrity in the endothelial lining of the superficial blood vessels. Reassurance and sunscreen use are the only treatments necessary. The aspirin will exacerbate the capillary leakage as seen here but will not be the cause of the lesion.
David L. Kaplan, MD, is a clinical assistant professor of dermatology at the University of Missouri–Kansas City School of Medicine in Kansas City, Missouri, and at the University of Kansas School of Medicine in Kansas City, Kansas. He practices adult and pediatric dermatology in Overland Park, Kansas.