What Is It, Causes, Treatment, and More
Author:Anna Hernánez, MD
Editors:Alyssa Haag,Emily Miao, PharmD,Kelsey LaFayette, DNP, ARNP, FNP-C
Illustrator:Jessica Reynolds, MS
Copyeditor:David G. Walker
What is seborrheic dermatitis?
Seborrheic dermatitis is a common inflammatory skin condition characterized by erythematous, well-demarcated plaques with yellow, greasy scales. It typically affects areas with a high density of sebaceous or oil-producing glands, such as the scalp, face, ears, and upper chest. Seborrheic dermatitis has a bimodal distribution with peaks of incidence at 2 to 12 months of age and in early adulthood. When seborrheic dermatitis occurs in infants, it typically affects the scalp and is commonly referred to as “cradle cap.” Though seborrheic dermatitis can be treated with several medications, it is a chronic, relapsing disorder for which long-term treatment is often necessary.
What causes seborrheic dermatitis?
The exact cause of seborrheic dermatitis is not currently known, but it is believed to involve a number of genetic and environmental factors as it tends to worsen with stress and during the cold and dry winter months. Colonization of the skin by Malassezia yeast, a component of the skin flora that thrives in oil-rich skin, is also believed to play a significant role. It is thought that, in predisposed individuals, Malassezia invades the outermost layer of the skin, causing an inflammatory reaction triggered by the fungi and the local irritants it produces. Additionally, seborrheic dermatitis has been associated with various conditions, including neurological disorders, like stroke and Parkinson disease, as well as immunodeficiency, like an HIV infection. Nutritional deficiencies of biotin, vitamin B6, and vitamin B2 have also been linked with seborrheic dermatitis in children.
What are the signs and symptoms of seborrheic dermatitis?
Signs and symptoms of seborrheic dermatitis include red areas of inflamed skin with greasy-looking, yellowish scales that affect areas with a high density of sebaceous glands, such as the scalp, face, behind the ears, and upper chest.
In infants, seborrheic dermatitis tends to affect the scalp, and it is commonly referred to as “cradle cap.” However, it can also cause redness and scaling in the face, ears, neck, diaper area, and skin folds. Unlike in adults, seborrheic dermatitis does not usually cause itching in infants. In some cases, a thick layer of yellowish, greasy-looking scale can cover the entire scalp. Over time, the scale becomes flaky and typically brushes off with the condition self-resolving in a few months.
In adults, seborrheic dermatitis is a chronic, relapsing condition that typically affects the scalp, face, and upper trunk. Dandruff is considered to be a mild form of seborrhoeic dermatitis where inflammation is not present. It is characterized by light flaking on the scalp that may spread to the hairline, retroauricular area, and eyebrows. More severe forms of scalp seborrheic dermatitis present with visible inflammation, consisting of patchy, orange to salmon-colored plaques covered with greasy scaling. Lesions may extend to the retroauricular area, where they often develop fissures, oozing, and crusting and to the outer canal of the ear, sometimes with intense itchiness and secondary bacterial infection.
On the face, seborrheic dermatitis tends to affect the eyebrows, eyelids, and nasolabial folds, though lesions may extend to the cheeks and malar areas in a butterfly distribution. In some cases, there may be redness of the free margin of the eyelids and yellow crusting within the eyelashes, leading to blepharitis (i.e., inflammation of the eyelids).
Seborrheic dermatitis in the trunk is less common, and it often affects moist, skin-to-skin contact regions, such as the armpits, under the breasts, and the groin. In individuals with HIV, seborrheic dermatitis tends to be more extensive and severe, and it sometimes involves unusual sites, such as the extremities.
How is seborrheic dermatitis diagnosed?
Diagnosis of seborrheic dermatitis is often made clinically based on the distribution of the lesions and appearance of the skin in affected areas. Generally, there is no need to conduct additional tests, but a skin biopsy may be performed if the diagnosis is uncertain. Common skin conditions that may resemble seborrheic dermatitis include psoriasis, atopic dermatitis, rosacea, and systemic lupus erythematosus.
How is seborrheic dermatitis treated?
Treatment of seborrheic dermatitis varies according to the severity of the condition. In infants, cradle cap can be treated with frequent shampooing with non-medicated baby shampoo or emollients, like petroleum jelly or baby oil, to help loosen the scales. The softened scales can then be removed with a cloth or soft toothbrush. More extensive or persistent cases may require short-term treatment with a topical antifungal cream or low-potency topical corticosteroid.
Adult individuals with mild disease that presents as minimal scalp scaling are generally treated with over-the-counter dandruff shampoos containing selenium sulfide, zinc pyrithione, or coal tar as well as antifungal agents, like shampoos or creams, until remission is achieved.On the other hand, individuals with moderate to severe seborrheic dermatitis who have greasy scaling, inflammation, and itchiness may receive treatment with topical antifungals (e.g., ketoconazole, ciclopirox) alone or in combination with a topical corticosteroid. Topical corticosteroids, such as hydrocortisone, fluocinolone, and betamethasone, can be beneficial to reduce flare-ups, but its long-term use is associated with side effects (e.g., skin atrophy, telangiectasias). Other treatments, such as topical calcineurin inhibitors (e.g., pimecrolimus cream) and oral antifungals, may be used if first-line treatments are not effective. Because seborrheic dermatitis is a chronic condition, antifungal creams or shampoos may be used intermittently as maintenance therapy to prevent recurrences.
What are the most important facts to know about seborrheic dermatitis?
Seborrheic dermatitis is an inflammatory skin condition characterized by erythematous, well-demarcated plaques with yellow, greasy scales that typically affect the scalp, face, and upper chest. This condition typically worsens during the winter months and in periods of stress and poor general health. Diagnosis is clinical, and treatment includes topical antifungal agents, like shampoos or creams. In severe cases, topical antifungals can be combined with low potency topical corticosteroids such as hydrocortisone.
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Resources for research and reference
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Clark GW, Pope SM, Jaboori KA. Diagnosis and treatment of seborrheic dermatitis. American Family Physician. 2015;91(3):185-190. https://www.aafp.org/pubs/afp/issues/2015/0201/p185.html
de Avelar Breunig J, de Almeida Jr HL, Duquia RP, Souza PRM, Staub HL. Scalp seborrheic dermatitis: prevalence and associated factors in male adolescents. International Journal of Dermatology. 2011;51(1):46-49. doi:https://doi.org/10.1111/j.1365-4632.2011.04964.x
Hoi HT. Seborrheic Dermatitis and traditional treatments. International Journal of Psychosocial Rehabilitation. 2020;(14757192):1537-1545. doi:https://doi.org/10.37200/ijpr/v24i2/pr200457Vijaya Chandra SH, Srinivas R, Dawson TL, Common JE. Cutaneous Malassezia: commensal, pathogen, or protector? Frontiers in Cellular and Infection Microbiology. 2021;10. doi:https://doi.org/10.3389/fcimb.2020.614446