Seborrhoeic dermatitis (also Seborrheic dermatitis AmE, seborrhea) (also known as “Seborrheic eczema”) is a skin disorder affecting the scalp, face, and trunk causing scaly, flaky, itchy, red skin. It particularly affects the sebum-gland rich areas of skin.
Seborrhoeic dermatitis may be visually unpleasant and moderately itchy but is a harmless condition. The condition is often persistent but is easily controlled using readily available medication. After treatment, the condition may recur after a time lapse of months or years.
As with other dermatitis conditions, seborrhoeic dermatitis is often loosely defined as a form of eczema although it differs from other more serious conditions more properly defined as eczema.
The cause of seborrheic dermatitis remains unknown, although many factors have been implicated. The widely present yeast, Malassezia furfur (formerly known as Pityrosporum ovale), is involved, as well as genetic, environmental, hormonal, and immune-system factors. The claim that seborrhoeic dermatitis is an inflammatory response to the yeast has not been proven. Those afflicted with seborrheic dermatitis have an unfavorable epidermic response to the infection, with the skin becoming inflamed and flaking.
Hair lossIn children, excessive vitamin A intake can cause seborrhoeic dermatitis. Lack of biotin, pyridoxine (vitamin B6) and riboflavin (vitamin B2) may also be a cause.
Side effects to inflammation may include temporary hair loss. If severe outbreaks are untreated for extended intervals, permanent hair loss may result, because of damage to hair follicles.
Soaps and detergents such as sodium laureth sulfate may precipitate a flare-up, as they strip moisture from the top layers of the skin, and the drying property of these can cause flare-ups and may worsen the condition. Accordingly a suitable alternative should be used instead.
Among dermatologist-recommended treatments are shampoos containing coal tar, ciclopiroxolamine, ketoconazole, selenium sulfide, or zinc pyrithione. For severe disease, keratolytics such as salicylic acid or coal tar preparations may be used to remove dense scale. Topical terbinafine solution (1%) has also been shown to be effective in the treatment of scalp seborrhoea, as may lotions containing alpha hydroxy acids or corticosteroids (such as fluocinolone acetonide). Pimecrolimus topical lotion is also sometimes prescribed.