THERAPEUTICS FOR THE CLINICIAN Safe and Effective Treatment of Seborrheic Dermatitis Boni E. Elewski, MD Seborrheic dermatitis is a common chronic inflam- eborrheic dermatitis, a common skin disorder matory skin disorder that can vary in presentation that typically presents as erythematous plaques from mild dandruff to dense, diffuse, adherent S or patches, can vary from mild dandruff to dense, scale. The disorder occurs throughout the world diffuse, adherent scale affecting areas of the head and without racial or geographic predominance; it is trunk where sebaceous glands are prominent, includ- more common in males than females. Its precise ing the scalp, nasolabial folds, chest, eyebrows, and etiology remains unknown, but the condition is ears. A chronic inflammatory disorder, its precise eti- strongly associated with lipophilic Malassezia ology remains unknown, though it is associated with yeasts found among the normal skin flora and genetic, environmental, and general health factors, as represents a cofactor linked to several risk well as lipophilic Malassezia yeasts.1,2 factors, including T-cell depression, increased In seborrheic dermatitis, plaques typically appear sebum levels, and activation of the alternative as red, flaky, greasy-looking patches of skin; the complement pathway. The goal of treatment amount of flaking and erythema varies from patient is symptom control, with an emphasis on the to patient. Seborrheic dermatitis typically presents as importance of maintaining patient adherence to a condition of the scalp, which is a unique environ- therapy to achieve low rates of recurrence. Avail- ment in humans—warm and dark, and particularly able therapies include corticosteroids, antifungal hospitable to infections and infestations introduced agents, immunomodulators, and medicated kera- by fingers, hats, combs, or styling implements.3 Dis- tolytic shampoos. Although corticosteroids are tribution is symmetric, commonly presenting in hairy associated with recurrence, they sometimes may areas of the head (ie, scalp, scalp margin, eyebrows, be recommended in combination with antifungal eyelashes, beard, mustache) but also on the forehead agents. Antifungal therapy is considered primary, and in external ear canals; nasolabial folds; and body but some agents are more effective than others folds, including the axillae, navel, groin, and infra- because of their favorable pharmacokinetic pro- mammary and anogenital areas.2 Lesions typically files, high rates of absorption, anti-inflammatory worsen during the winter, while sun exposure during and antipruritic properties, and vehicle. the warmer months appears to improve the clinical Cutis. 2009;83:333-338. appearance of the disease.4 Scratching and emotional stress tend to aggravate the condition.5,6 EPIDEMIOLOGY OF SEBORRHEIC DERMATITIS Accepted for publication April 17, 2009. To emphasize the widespread prevalence of seborrheic From the University of Alabama, Birmingham. dermatitis, some authors have noted that dandruff, Supported by an educational grant from Ortho Dermatologics, the mildest form of seborrheic dermatitis,7 occurs in a division of Ortho-McNeil-Janssen Pharmaceuticals, Inc. 15% to 20% of the population, though it is important Dr. Elewski owns shares of Johnson & Johnson and is a consultant to differentiate between seborrheic dermatitis of the for Ortho Dermatologics. The University of Alabama received a 1 research grant from Ortho Dermatologics. scalp and any scalp flaking, regardless of etiology. In Correspondence: Boni E. Elewski, MD, The Eye Foundation general, the prevalence of seborrheic dermatitis ranges Professional Building, 700 18th St S, EFH 414, Birmingham, AL 35233. from 1% to 3% in the immunocompetent population7 VOLUME 83, JUNE 2009 333 Therapeutics for the Clinician and greatly increases in the immunocompromised The epidemiology of dermatologic disease rarely population, particularly patients with AIDS.6 has been studied in populations with skin of color, Seborrheic dermatitis is more common in males though the report of one US survey comparing the than females, probably because androgens stimulate most commonly treated dermatologic conditions in sebum production. In general, the condition ini- black and white patients found seborrheic dermatitis tially appears during the teenaged years or 20s, with to be among the top 5 diagnoses in black patients a waxing and waning course throughout adulthood.2 but not white patients.9 Adolescents, young adults, and adults older than 50 years are most commonly affected; however, an ETIOLOGY OF SEBORRHEIC DERMATITIS Australian survey of 1116 children aged 11 days to Dawson10 emphasized that seborrheic dermatitis must 5 years 11 months found the overall prevalence of be viewed as more than a superficial disorder of the seborrheic dermatitis to be 10.0% in boys and 9.5% stratum corneum. It is a condition in which the epi- in girls, suggesting that the condition also is com- dermis is substantially altered by hyperproliferation, mon in early childhood.8 excess intercellular and intracellular lipids, interdigi- Seborrheic dermatitis occurs throughout the tation of the corneal envelope, and parakeratosis. The world in patients of various ethnicities and races. etiology of seborrheic dermatitis appears to depend Table 1. Seborrheic Dermatitis Risk Factors1,6 Risk Factor Description Lipids and hormones Distribution of lesions on the body corresponds to the distribution of sebaceous glands, with excess sebum found on the scalp, nasolabial folds, chest, eyebrows, and ears Most common in adolescents and young adults (when sebaceous glands are most active) and adults older than 50 years Comorbid conditions Parkinson disease Cranial nerve palsies Truncal paralyses Mood disorders HIV/AIDS Some cancers Alcoholic pancreatitis Down syndrome Immunologic factors Depressed levels of helper T cells Reduced phytohemagglutinin, concanavalin A stimulation Lower antibody titers Lifestyle factors Poor nutrition Inadequate hygiene practices Abbreviation: HIV, human immunodeficiency virus. 334 CUTIS® Therapeutics for the Clinician on 3 factors: sebaceous gland secretions, microfloral TREATMENT OF SEBORRHEIC DeRMATITIS metabolism, and individual susceptibility.10 Many Seborrheic dermatitis is a chronic disease and factors have been cited as possible contributors to the patients should be informed about the risk for relapse, development of seborrheic dermatitis (Table 1). predisposing factors, and the lifetime need for special attention to hygiene. To remove oils and generally Role of Malassezia Species improve the skin, patients should be encouraged to Yeasts of the genus Malassezia (formerly Pityrosporum) cleanse the affected skin often with soap and water. are a normal part of the skin flora yet are associated Patients should engage in outdoor recreation, particu- with many common dermatologic disorders, including larly in the summer, with the goal of improving the tinea (or pityriasis) versicolor and Malassezia folliculi- condition through exposure to sunlight, providing tis. Following some debate in the literature evaluating precautions are taken against sun damage.2 if yeasts are of primary pathogenic significance or a secondary phenomenon, it has become clear that PHARMACOLOGIC OPTIONS lipid-dependent Malassezia yeasts are causal factors The primary goal of therapy for seborrheic dermatitis in the development of seborrheic dermatitis, most is symptom control because, at this time, there is no commonly Malassezia globosa, with its high lipase cure for the disease. Various treatments are used for activity, and Malassezia restricta. These 2 organisms seborrheic dermatitis, including mild corticosteroids, predominate on the scalp of individuals with sebor- antifungal agents, immunomodulators, and medicated rheic dermatitis or dandruff.7,10 Because the disease shampoos.11 Although mild corticosteroids used alone responds to antifungal medications and Malassezia can be effective in managing symptoms, the disease is counts diminish as the condition improves, it has likely to recur quickly once steroid therapy is stopped. been strongly suggested that yeasts play a role in the Antifungal agents should therefore be considered pathogenesis of seborrheic dermatitis. Genetic and primary therapy.5,12 environmental factors as well as comorbid conditions Because seborrheic dermatitis is a chronic recur- may predispose certain populations to the develop- ring skin disorder, the goal of treatment is the devel- ment of seborrheic dermatitis.2 In general, patients opment of a safe and effective regimen associated with seborrheic dermatitis are thought to have higher with low rates of recurrence.12 Accordingly, treat- Malassezia counts than healthy controls, though some ment should incorporate an antifungal agent that is experts dispute this assumption.1 effective and tolerable to the patient, both to reduce relapse and to promote patient adherence. An opti- Other Risk Factors mal topical agent is one with good penetration that It also has been observed that individuals with central stays on the skin; has anti-inflammatory properties; nervous system disorders appear to be prone to developing and is delivered via a vehicle that enhances penetra- extensive seborrheic dermatitis that often is refractory to tion, provides a healing environment, and sustains treatment. In these cases, it has been hypothesized that the infection results from excessive pooling of sebum caused by immobility, which permits increased growth Table 2. 2 of yeasts. Another