A 50-year-old man presented to the emergency department with mild lower-extremity edema and a petechial rash on both legs that stopped at the sock line. He had been out of town traveling the previous week, and he didn't remember any sick contacts.
He had not used new soap and didn't remember insects in his hotel room. He had never had a rash or edema on his extremities in the past. The rash was mildly irritating. He also said he had no chest pain, shortness of breath, or fever, but reported a mild headache and body aches, which he attributed to dehydration.
The physical exam revealed a rash similar to the one shown, with petechia and mild edema that spared the sock line. He also had redness on all sun-exposed areas. Labs, including creatine kinase, C-reactive protein, erythrocyte sedimentation rate, CBC, and coagulation studies, were normal. His chest x-ray was unremarkable.
The patient said he felt better after receiving a liter of fluid and ibuprofen, and asked to be discharged home. Then the patient's family arrived, and his children were wearing mouse ears. He then reported that he ran a marathon the previous week, played golf with friends, and went to Disney World.
Find the diagnosis and case discussion on next page.
Diagnosis: Exercise-Induced Vasculitis
Although called by many names (Disney rash, Epcot rash, golfer's rash, and hiker's rash), the medical term for this finding is exercise-induced vasculitis. It is often misdiagnosed as an allergic reaction, insect bites, heart failure, or secondary to thrombocytopenia or other hematologic abnormalities.
The rash is most common in women over 50, but should be considered in any patient who has been exercising or walking in a warm environment. (CMAJ. 2018;190:E195; https://bit.ly/2ZnxfUf.) One study described 99 patients who presented with purpuric rashes on exposed lower legs after exercising in a warm environment. (Am J Clin Dermatol 2016;17:635.) The skin under socks, stockings, or tight pants is consistently spared in these cases because of the protective mechanism of compression.
Exercise-induced vasculitis is not fully understood, but it is thought to be secondary to muscle fatigue in the lower extremities, resulting in venous pooling and complement activation during prolonged exercise and hot weather. This presents clinically as mild edema and a petechial rash to the ankle area, sparing the sock area.
Histological biopsies most often show leukoclastic vasculitis. Symptoms typically resolve within 10 days, but relapse occurs in 77.5 percent of the patients. (Am J Clin Dermatol 2016;17:635.)
Treatment is aimed at reducing muscle fatigue, venous pooling, and inflammation. Oral NSAIDs, topical steroids, compression socks, and elevating the legs after activity are recommended as prevention and treatment.
This case highlights not only a common and benign case of self-limiting vasculitis but also the importance of history-taking in medical exams. The physician may have had other concerns and reasons to obtain lab work, but this case could have been quickly solved without the need for further tests and radiation.
EPs operate on pattern recognition, so keep this case and knowledge of exercise-induced vasculitis in your back pocket if you see a patient who has exercised in warm weather and has a new rash and edema that spare the sock.
Dr. Eutermoseris an assistant professor of emergency medicine at Denver Health and University of Colorado Hospital.