Multiple pigmented patches
An 80-year-old woman presented to her family physician’s office for evaluation of upper respiratory symptoms. During the appointment, she mentioned a dark rash that had been on her back for 20 years and asked if there was something she could use for the itching. The discoloration started after she had received chemotherapy for ovarian cancer 20 years earlier. She had tried multiple topical creams, but none provided relief.
What’s your diagnosis?
This patient was given a diagnosis of erythema dyschromicum perstans (EDP), also known as ashy dermatosis because of the hyperpigmented macules that come together into confluent patches that look like burned wood. There is often an inflammatory erythematous aspect to EDP.
The etiology of EDP is unknown. It is not related to sun exposure and occurs most commonly on the trunk. Although there are case reports implicating medications or infections, no clear connection has been found. This patient’s chemotherapy may have been an inciting factor, based on her history, but it is not likely that cancer caused the EDP.
EDP tends to be chronic and difficult to treat. Fortunately, other than the itching and skin discoloration, it is usually asymptomatic and benign. Large-scale trials are lacking, but there are case reports showing benefit from narrow beam UVB treatments and topical tacrolimus.1 Laser has not proven very helpful, and the hyperpigmentation can recur.
Based on the clinical appearance of this patient’s lesion, and the fact that a previous biopsy in the same location was consistent with her diagnosis, no further testing was performed. The patient was advised to apply topical diphenhydramine to her back 4 times daily for a 2-week trial. If the diphenhydramine failed to provide relief, the next step in her treatment would have been topical tacrolimus.
Photo and text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque.