Dandruff

Key Points
Condition is a common harmless scaling rash affecting the face, scalp and other areas.
A common uninflamed form of seborrhoeic dermatitis is commonly called dandruff.
Condition results in scaly flakes of dry pink or skin-colored patches with yellowish or white scale that can appear in the hair, the eyebrows, eyelids, or in creases and folds.
Causes are unknown, but can be exacerbated by certain factors.

Seborrheic dermatitis is a common, harmless, scaling rash affecting the face, scalp and other areas. It is most likely to occur where the skin is oily. Dandruff, sometimes called pityriasis capitis, is an uninflamed form of seborrheic dermatitis. Dandruff presents as scaly patches scattered within hair-bearing areas of the scalp. Seborrheic dermatitis may appear at any age after puberty. It fluctuates in severity and may persist for years. It may predispose to psoriasis. Sometimes it is difficult to tell psoriasis from seborrheic dermatitis on the face, scalp and chest and your doctor may diagnose an overlap condition, known as sebopsoriasis.

Within the scalp, seborrheic dermatitis causes ill-defined dry pink or skin colored patches with yellowish or white bran-like scale. It may spread to affect the entire scalp.

Seborrheic dermatitis is common within the eyebrows, on the edges of the eyelids, inside and behind the ears and in the creases beside the nose. It can result in pale pink round or ring shaped patches on the hairline. Sometimes it affects the skin-folds of the armpits and groin, the middle of the chest or upper back. It causes salmon-pink flat patches with a loose bran-like scale, sometimes in a ring shape. It may or may not be itchy and can be quite variable from day to day.

Seborrheic dermatitis is believed to be an inflammatory reaction related to a excessive normal skin yeast. The main species is Pityrosporum ovale, an oil loving yeast normally found in the scalp and other oily regions of the skin. Patients with seborrhoeic dermatitis appear to have a genetic tendency to develop this reaction to their normal skin yeast. Seborrhoeic dermatitis is not contagious or related to diet, but it may be aggravated by illness, psychological stress, fatigue, change of season and reduced general health. Those with immunodeficiency (especially infection with HIV) and with neurological disorders such as Parkinson’s disease and stroke are particularly prone to it. Decreasing the yeast numbers usually results in improvement of the condition.

Differential Diagnosis (Other conditions with similar appearance)
Psoriasis
Atopic Dermatitis
Impetigo
intertrigo
tinea capitis

Diagnosis

Key Points
Diagnosis is performed through clinical inspection to confirm diagnosis.

Treatment
Key Points
Treatment on the scalp can be done with medicated shampoos, steroid scalp applications, and tar cream.
*Treatment on other parts of the body can be done with creams, cleansers, steroid treatments, and in severe cases antifungal medications or ultraviolet radiation.

Seborrheic dermatitis in adults may be very persistent. However, it can generally be kept under control with regular use of antifungal agents and intermittent applications of Topical steroids. Treatment of seborrheic dermatitis of the scalp can be treated with medicated shampoos (many work by reducing yeast load of skin), steroid scalp applications (calming inflammation), and tar shampoo. Other parts of the body can be treated with non-soap cleansers, ketoconazole or ciclopirox cream, hyrodcortisone cream, topical calcineurin inhibitors, and in severe cases, oral antifungal medications.