Seborrhoeic eczema

Seborrhoeic dermatitis, sometimes inaccurately referred to as seborrhoea, is a long-term skin disorder. Symptoms include red, scaly, greasy, itchy, and inflamed skin. Areas of the skin rich in oil-producing glands are often affected including the scalp, face, and chest. It can result in social or self-esteem problems. In babies, when the scalp is primarily involved, it is called cradle cap. Dandruff is a milder form of the condition without inflammation.

The cause is unclear but believed to involve a number of genetic and environmental factors. Risk factors include poor immune function, Parkinson's disease, and alcoholic pancreatitis. The condition may worsen with stress or during the winter. The ''Malassezia'' yeast is believed to play a role. It is not a result of poor hygiene. Diagnosis is typically based on the symptoms. The condition is not contagious.

The typical treatment is antifungal cream and anti-inflammatory agents. Specifically, ketoconazole or ciclopirox are effective. It is unclear if other antifungals, such as miconazole, are equally effective as they have been poorly studied. Other options may include salicylic acid, coal tar, benzoyl peroxide, and phototherapy.

The condition is most common in infants within the first 3 months or in adults aged 30 to 70 years. In adults between 1% and 10% of people are affected. Males are more often affected than females. Up to 70% of babies may be affected at some point in time.

Signs and symptoms

Seborrhoeic dermatitis' symptoms appear gradually, and usually the first signs are flaky skin and scalp. Symptoms occur most commonly anywhere on the skin of the scalp, behind the ears, on the face, and in areas where the skin folds. Flakes may be yellow, white or grayish. Redness and flaking may also occur on the skin near the eyelashes, on the forehead, around the sides of the nose, on the chest, and on the upper back.

In more severe cases, yellowish to reddish scaly pimples appear along the hairline, behind the ears, in the ear canal, on the eyebrows, on the bridge of the nose, around the nose, on the chest, and on the upper back.

Commonly, patients experience mild redness, scaly skin lesions and in some cases hair loss. Other symptoms include patchy scaling or thick crusts on the scalp, red, greasy skin covered with flaky white or yellow scales, itching, soreness and yellow or white scales that may attach to the hair shaft.

Seborrhoeic dermatitis can occur in infants younger than three months and it causes a thick, oily, yellowish crust around the hairline and on the scalp. Itching is not common among infants. Frequently, a stubborn diaper rash accompanies the scalp rash.

Causes

The cause of seborrhoeic dermatitis has not been fully clarified.

In addition to the presence of ''Malassezia'', genetic, environmental, hormonal, and immune-system factors are necessary for and/or modulate the expression of seborrhoeic dermatitis. The condition may be aggravated by illness, psychological stress, fatigue, sleep deprivation, change of season, and reduced general health. In children and babies, excessive vitamin A intake or issues with Δ⁶-desaturase enzymes have been correlated with increased risk. Seborrhoeic dermatitis-like eruptions are also associated with vitamin B₆ deficiency. Those with immunodeficiency (especially infection with HIV) and with neurological disorders such as Parkinson's disease (for which the condition is an autonomic sign) and stroke are particularly prone to it.

Climate

Low humidity and low temperature are responsible for high frequency of seborrheic dermatitis.

Fungi

The condition is thought to be due to a local inflammatory response to over-colonization by ''Malassezia'' fungi species in sebum-producing skin areas including the scalp, face, chest, back, underarms, and groin. This is based on observations of high counts of ''Malassezia'' species in skin affected by seborrhoeic dermatitis and on the effectiveness of antifungals in treating the condition. Such species of ''Malassezia'' include ''M. furfur'' (formerly '' Pityrosporum ovale''), ''M. globosa'', ''M. restricta'', ''M. sympodialis'', and ''M. slooffiae''. Although ''Malassezia'' appears to be the central predisposing factor in seborrhoeic dermatitis, it is thought that other factors are necessary for the presence of ''Malassezia'' to result in the pathology characteristic of the condition. This is based on the fact that summer growth of ''Malassezia'' in the skin alone does not result in seborrhoeic dermatitis. Besides antifungals, the effectiveness of anti-inflammatory drugs, which reduce inflammation, and antiandrogens, which reduce sebum production, provide further insights into the pathophysiology of seborrhoeic dermatitis.

Management

Humidity

A humidifier can be used to prevent low indoor humidity during winter (especially with indoor heating), and dry season. And a dehumidifier can be used during seasons with excessive humidity.

Medications

A variety of different types of medications are able to reduce symptoms of seborrhoeic dermatitis. These include certain antifungals, anti-inflammatory agents like corticosteroids and nonsteroidal anti-inflammatory drugs, antiandrogens, and antihistamines, among others.

Antifungals

Regular use of an over-the-counter or prescription antifungal shampoo or cream may help those with recurrent episodes. The topical antifungal medications ketoconazole and ciclopirox have the best evidence. It is unclear if other antifungals are equally effective as this has not been sufficiently studied. Antifungals that have been studied and found to be effective in the treatment of seborrhoeic dermatitis include ketoconazole, fluconazole, miconazole, bifonazole, sertaconazole, clotrimazole, flutrimazole, ciclopirox, terbinafine, butenafine, selenium sulfide