Seborrhoeic dermatitis

Seborroeic dermatitis or its other name - seborroeic eczema - is a common skin condition which affects both adults and children. The version which affects babies and young children is called cradle cap. It affects adults aged 18 to 40 and men more than women. It appears as red, itchy or inflamed patches of the skin on the scalp, face and body. But it can also affect other areas such as folds of skin beneath the breasts.

It develops in those areas of the body which tend to be oily or greasy such as the forehead or scalp.

It is a harmless condition but can persist for a long period of time. It does have a tendency to recur so flare ups are common. These can be triggered from any number of reasons, e.g. stress or a chronic illness such as Parkinson’s disease.

Symptoms of seborrhoeic dermatitis

These vary depending upon which part of the body is affected. In general, the afflicted area of skin will be covered with white or yellow coloured patches (scales). These will be greasy looking and sore or itchy.

These symptoms usually ease during the summer but flare up again in the winter months. Areas commonly affects include:

• Scalp: manifests itself as dandruff (white, flakes of skin which are formed from dead skin cells).
• Ears: if it forms inside the ears it can irritate the ear canal and cause otitis externa.
• Face: it appears on the eyebrows and/or eyelids and around the nose.
• Chest: patches of skin develop on the chest and between the shoulder blades.

It also appears in folds of skin in the groin, underneath the breasts or the armpits. These areas of the body tend to trap moisture and so are ideal breeding grounds for a skin rash.

Babies tend to develop this on the scalp (cradle cap), behind the ears or on the eyebrows/eyelids. It can also develop in the groin although it is often mistaken for nappy rash.

Causes of seborrhoeic dermatitis

Experts are not entirely sure what causes this condition but one possible cause is a yeast called Malassezia. This yeast lives on the surface of our skin but people who are susceptible to seborrhoeic dermatitis have a greater concentration of this. They may also have less resistance to this type of yeast. People suffering from HIV/AIDS or Parkinson’s disease are prone to developing this condition. Other possible causes include a side effect of certain medications and extreme tiredness.

How is it diagnosed?

A GP can make a diagnosis just by looking at the infected area.

This is usually sufficient but the only exception to this is if the patient has seborrhoeic dermatitis on their scalp. This can look almost identical to seborrhoeic psoriasis and in some cases, the two overlap each other.

Treating seborrhoeic dermatitis  

Mild cases usually respond to over the counter remedies such as anti-dandruff shampoo or a medicated shampoo which contains ketoconazole or selenium sulphide. These are recommended for scalp based seborrhoeic dermatitis.

Those which affect the face and body are treated with prescription medicines such as antibiotics or steroid creams.

Severe cases or those which do not respond to treatment will require further investigation by a dermatologist.

Babies and seborrhoeic dermatitis

The treatment described above is designed for adults. Babies with this condition (cradle cap) can be treated by applying a special baby shampoo to the scalp before brushing away the scaly patches. This is discussed in greater detail in our cradle cap treatment section.