Seborrheic dermatitis

Seborrheic dermatitis is a common, inflammatory skin condition that causes flaky, white to yellowish scales to form on oily areas such as the scalp or inside the ear. It can occur with or without reddened skin.

Cradle cap is the term used when seborrheic dermatitis affects the scalp of infants.

Causes

Seborrheic dermatitis is thought to be due to a combination of an over production of skin oil and irritation from a yeast called malessizia.

Seborrheic dermatitis appears to run in families. Stress, fatigue, weather extremes, oily skin, infrequent shampoos or skin cleaning, use of lotions that contain alcohol, skin disorders (such as acne), or obesity may increase the risk.

Neurologic conditions, including Parkinson's disease, head injury, and stroke may be associated with seborrheic dermatitis. Human immunodeficiency virus (HIV) has also been linked to increased cases of seborrheic dermatitis.

Symptoms

Seborrheic dermatitis can occur on many different body areas. Typically it forms where the skin is oily or greasy. Commonly affected areas include the scalp, eyebrows, eyelids, creases of the nose, lips, behind the ears, in the external ear, and along skin folds on the middle of the body.

Seborrheic dermatitis in infants, also called cradle cap, is a harmless, temporary condition. It appears as thick, crusty, yellow or brown scales over the child's scalp. Similar scales may also be found on the eyelids, ear, around the nose, and in the groin. Cradle cap may be seen in newborns and small children up to age 3 .

Cradle cap is not contagious, nor is it caused by poor hygiene. It is not an allergy, and it is not dangerous. Cradle cap may or may not itch. If it itches, excessive scratching of the area may cause additional inflammation, and breaks in skin may cause mild infections or bleeding.

In general, symptoms of seborrheic dermatitis include:

* Skin lesions
* Plaques over large area
* Greasy, oily areas of skin
* Skin scales -- white and flaking, or yellowish, oily, and adherent -- "dandruff"
* Itching -- may become more itchy if infected
* Mild redness
* Hair loss

Exams and Tests

The diagnosis is based on the appearance and location of the skin lesions.

Treatment

You can treat flaking and dryness with over-the-counter dandruff or medicated shampoos. Shampoo the hair vigorously and frequently (preferably daily). Loosen scales with the fingers, scrub for at least 5 minutes, and rinse thoroughly. Active ingredients in these shampoos include salicylic acid, coal tar, zinc, resorcin, ketoconazole, or selenium.

Shampoos or lotions containing selenium, ketoconazole, or corticosteroids may be prescribed for severe cases. To apply shampoos, part the hair into small sections, apply to a small area at a time, and massage into the skin. If on face or chest, apply medicated lotion twice per day.

Seborrheic dermatitis may improve in the summer, especially after outdoor activities.

For infants with cradle cap:

1. Massage your baby's scalp gently with your fingers or a soft brush to loosen the scales and improve scalp circulation.
2. Give your child daily, gentle shampoos with a mild soap while scales are present. After scales have disappeared, you may reduce shampoos to twice weekly.
3. Be sure to rinse off all soap.
4. Brush your child's hair with a clean, soft brush after each shampoo and several times during the day.
5. If scales do not easily loosen and wash off, apply some mineral oil to the baby's scalp and wrap warm, wet cloths around his head for up to an hour before shampooing. Then, shampoo as directed above. Remember that your baby loses a lot of heat through his scalp. If you use warm, wet cloths with the mineral oil, check frequently to be sure that the cloths have not become cold. Cold, wet cloths could drastically reduce your baby's temperature.
6. If the scales continue to be a problem or concern, or if you child seems uncomfortable or scratches his scalp, contact your physician. He may prescribe a cream or lotion to apply to your baby's scalp several times a day.

Outlook (Prognosis)

Seborrheic dermatitis is a chronic (life-long) condition that can be controlled with treatment. It often has extended inactive periods followed by flare-ups.
Possible Complications

* Psychological distress, low self esteem, embarrassment
* Secondary bacterial or fungal infections

When to Contact a Medical Professional

Call for an appointment with your health care provider if seborrheic dermatitis symptoms do not respond to self-care or over-the-counter treatments.

Also call if patches of seborrheic dermatitis drain fluid or pus, form crusts, or become very red or painful.

Prevention

The severity of seborrheic dermatitis can be lessened by controlling the risk factors and by paying careful attention to skin care.

Alternative Names

Dandruff; Seborrheic eczema; Cradle cap

Itching scalp

Dandruff describes scaling and itching of the skin on the scalp. Dandruff causes white flakes on the scalp. Medicated or anti-dandruff shampoos can help. Seborrhoeic dermatitis has similar symptoms to dandruff. Cradle cap in babies is a form of seborrhoeic dermatitis. Psoriasis can also cause an itchy scalp.

Dandruff (pityriasis capitis) is the term used to describe simple scaling of the skin on the scalp. About 50 per cent of the population suffers from dandruff. Applying simple oils (for example, bath oil) to the scalp can be useful in the treatment of dandruff.

Why dandruff occurs
The top layer of the skin is constantly being shed and renewed. Although this usually goes unnoticed when it occurs on most areas of the body, it may become more visible on the scalp as the hair traps the scaling skin.

Itching scalp
Itching scalp, with or without scaling, is a very common problem. It commonly occurs in middle aged people, for no obvious reason. The usual response is to scratch, and this will often cause scratch marks and little crusty sores throughout the scalp. Dandruff can cause itching scalp. There are also a number of less common skin conditions that can present as itching in the scalp.

Seborrhoeic dermatitis can cause itching scalp
Seborrhoeic dermatitis is the name given to a red, itchy, scaly reaction in the scalp. It is similar to dandruff, except the scale is more marked and the scalp is often inflamed. It can be very itchy and can affect other parts of the body, including the face, eyebrows, beard and central chest area.

Seborrhoeic dermatitis symptoms
Symptoms of seborrhoeic dermatitis develop gradually and may include:

* Dry or greasy diffuse scaling of the scalp. This is the most usual presentation.
* Yellow-red scaling on those areas of the body that are generally affected in extreme disease - along the hairline, behind the hairs, on the eyebrows, on the bridge of the nose, over the sternum (middle of the chest), in the creases between the nose and the lips, and inside the ears.

Why it occurs
Seborrhoeic dermatitis affects areas with high densities of large oil glands. The inflammation is caused by the body’s reaction to a yeast on the scalp and to products that break down oil produced by the oil gland.

Cradle cap
Cradle cap is a form of seborrhoeic dermatitis that occurs in newborns. It results in a thick, yellow-crusted scalp lesion. Other symptoms can include:

* Splits in the skin and behind the ears
* Red facial pustules
* Stubborn nappy rash.

Older children can develop thick, stubborn plaques on the scalp, measuring one to two centimetres across.

Factors that can make seborrhoeic dermatitis worse
The incidence and severity of seborrhoeic dermatitis seems to be affected by:

* Other illnesses - for example, patients with neurologic disease (especially Parkinson’s disease) or HIV may have severe seborrhoeic dermatitis.
* Emotional or physical stress.
* Genetic factors.
* The season - seborrhoeic dermatitis is usually worse in winter.

Psoriasis can cause itching scalp
Psoriasis is a relatively common skin condition that affects about three per cent of the population. It is often confined to the scalp, elbows and knees. While seborrhoeic dermatitis tends to involve almost all the scalp, psoriasis often occurs in small, localised patches of redness with quite prominent thick scaling. Because psoriasis may only occur on the scalp, it can be mistaken for a severe case of dandruff. Psoriasis has a genetic link - there is often a family history of the condition. It may be triggered by some form of stress.

Medicated shampoos can help dandruff and itching scalp
Regular washing of the scalp with medicated soaps may be all that is required to relieve itching scalp. The most common anti-dandruff shampoos contain one or more of the following ingredients:

* Tar - shampoos containing tar have been used for years, usually for more severe scalp conditions. In the past, the scent of the tar-based shampoos made them less acceptable. However, newer preparations are well tolerated and simple to use.
* Selenium sulphide.
* Zinc pyrithione or zinc omadine.
* Piroctone olamine - this is the most recent addition to the medicated shampoos. It is known as a 'second generation' anti-dandruff agent. It is less toxic than zinc pyrithione and is therefore safer for family use.
* Antifungal agents.

How often to use medicated shampoos
How often you need to use medicated shampoos will depend on how severe your dandruff is and what treatment you are using. Always read the directions on the shampoo pack before using it. Some products are mild enough to be used every day, while others should only be used once a week. Over time, you will work out how often to use the shampoo to keep your dandruff under control.

Where to get help

* Your doctor
* Your local chemist
* Dermatologist
* Australasian College of Dermatologists website

Things to remember

* Dandruff affects about 50 per cent of the population.
* Itching scalp can be caused by a number of conditions, including dandruff, seborrhoeic dermatitis and psoriasis.
* Medicated shampoos can be used to treat dandruff and relieve itchy scalp.