Waxy loose scale with associated erythema on the face and scalp is a classic sign of seborrheic dermatitis (SD).
SD is caused by inflammation related to the presence of Malassezia, which proliferates on sebum-rich areas of skin. Malassezia is normally present on the skin, but some individuals have a heightened sensitivity to it, leading to erythema and scale. It is prudent to examine the scalp, nasolabial folds, and around the ears where it often occurs concomitantly.
There are multiple topical and systemic options which treat the fungal involvement, the subsequent inflammation, and reduce the scale.1 Topical azole antifungals are effective for reducing the amount of Malassezia present. Topical steroids work well to reduce the erythema. Fortunately, low-potency steroids, including hydrocortisone and desonide, are adequate. This is important since SD frequently involves the face and higher-potency steroids can cause skin atrophy or rebound erythema.
Salicylic acid products exfoliate the scale and topical tar products suppress the scale, both leading to clinical improvement. Sunlight and narrow beam UVB light therapy are also effective treatments. As was true with this patient, SD often improves during the summer months (when there is more sunlight) and when patients shave, as this allows for additional sun exposure to the skin.
The patient in this case was told to use ketoconazole shampoo for his scalp, beard, and mustache. He was instructed to use it at least 3 times per week, applying it to the scalp as the first part of his bathing routine and then waiting until the end to rinse it off. This technique maximizes the antifungal shampoo’s contact time on the skin. He was also given a prescription for ketoconazole cream to apply twice daily to the areas of facial erythema and scale. He was counseled that shaving his beard and mustache might help reduce the SD in those areas.
Photo and text courtesy of Daniel Stulberg, MD, FAAFP, Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque