Family doctor

Overview

Dandruff is a mild skin condition, usually confined to the scalp, that can cause irritation and embarrassment to the sufferer. Treatment can be simple. Switching to a good quality shampoo may solve the problem, and there are many over-the-counter treatment shampoos. For more persistent cases a doctor may advise hydrocortisone or coal-tar treatment. Advice from a doctor should be sought if dandruff is persistent or develops into sores or abscesses, as this could indicate a more serious condition.

What is dandruff?

Dandruff is the common term used for white skin flakes shedding from the scalp, or in some cases, other hair-covered skin. Dandruff is not contagious and usually not serious, although can be embarrassing and itchy.

Skin is naturally shed from the scalp, but in dandruff sufferers it becomes noticable on the shoulders and causes an itchy scalp. Seborrheic (seb-o-REE-ik) dermatitis is the technical term for this common condition.

Dandruff is usually due to the overworking of the sebaceous glands. These glands produce oil and help shed dead skin. In the case of a dandruff sufferer, the sebaceous glands are overactive, shedding more skin than usual.

Sometimes dandruff is caused by a naturally occurring yeast fungus called Pityrosporum ovale. Some people have more of this fungus than others, causing flaky scalp.

What are the symptoms?

Skin affected by seborrheic dermatitis is usually red and greasy with a white or yellowish flaky scale. The most common sites are the scalp but it can occur between the eyebrows, along the sides of the nose, behind the ears, in the external ear canal, over the breastbone, in the groin area, and sometimes in the armpits. Most dandruff is due to seborrheic dermatitis.

Related and similar conditions

Dandruff may also be caused by excessive dryness or by psoriasis. A few people have both conditions, which makes diagnosis difficult. Seborrheic dermatitis and psoriasis can be difficult to tell apart.

Psoriasis tends to have a whiter scale, and affected areas bleed fairly easily if plucked, picked or scratched. Patches of psoriasis also tend to be thicker and more persistent.

Rarely, seborrheic dermatitis will become infected, a condition known as impetigo.

Tinea capitis - scalp ringworm - may be mistaken for dandruff in adults. This condition is uncommon after puberty and when it appears on adults, the features different to those occurring on children. Tinea capitis will not respond to tradition dandruff treatments or antibotics. Lack of treatment can lead to scarring and permanent hairloss, as well as infection of others. The incidence of scalp ringworm in children is on the rise in the United Kingdom and several cases of adults - particulary those of Afro-Carribean descent - have been eventually diagonised with this condition after lengthy unnecessary investigations and treatments.

The vast majority of people with seborrheic dermatitis have no associated conditions. Sufferers of Parkinson's disease, spinal cord injuries and other neurological conditions and AIDS can have outbreaks of seborrheic dermatitis.

 How is dandruff treated?

Sometimes dandruff can be treated and prevented by using a good quality shampoo such as those sold by hairdressers. If dandruff does not disappear after a few weeks using a good shampoo, an anti-dandruff shampoo may solve the problem.

Shampoos contain one of five active ingredients: salicylic acid, coal-tar, zinc pyrithione, selenium sulfide and sulphur. These shampoos are non-prescription and the ingredients are approved for use by the United States Food and Drug Administration (FDA). Well known over-the-counter brands include Head and Shoulders, Denorex, Selsun Blue, Tegrin, Sebutone or Neutrogena T/Gel or T/Sal.

If necessary, shampoo daily with these shampoos, lathering well and making sure the lather remains on the scalp for 5 minutes before rinsing to allow the active ingredients to work. Take care with tar-based shampoos as they can stain light-coloured or grey hair and make the scalp more sun-sensitive. Anti-dandruff shampoos can make the hair brittle and weak, so use of a good hair conditioner is recommended.

When dandruff has cleared, begin using a good quality shampoo and rotate the use of the anti-dandruff shampoos as necessary. Some sufferers may need to try a range of anti-dandruff shampoos to gain best results, or rotate between various products, as continued use of one product seems to lose effectiveness over time.

A newer anti-fungal product containing Ketoconazole was approved in 1997 by the FDA in USA for over-the-counter sale in the form of Nizoral A-D shampoo. This medication can be helpful for particularly difficult cases, according to some pharmacists.

It should be noted there has been some concern over the use of Ketoconazole when using particular cholesterol-lowering drugs known as statins. Both medications compete for the same metabolism pathway via the liver and when Ketoconazole is taken orally, the toxicity of the statin can be increased. Theoretically, there may be a small effect using Nizoral shampoo as a topical product on the skin, so use of this product should probably be avoided if a statin is used, or doctor's advice sought.

If dandruff or itchy scalp persists for 3 weeks or the scalp becomes irritated or severely itchy, seek advice from a doctor. Prescription medication or creams may be able to help when over-the-counter shampoos do not. For instance, if shampoos aren't working an application of 1 % - 2.5 % hydrocortisone cream once or twice a day may be effective. If this too proves ineffective, a coal-tar preparation left on overnight may work. Sometimes a stronger corticosteroid preparation may be recommended.

A patchy, inflammatory scalp disorder not responding to usual treatments should have mycological samples sent for laboratory analysis to rule out Tinea capitis.

How can dandruff be prevented?

Dandruff may begin in infancy as cradle cap, then disappear until adolescence when oil glands become active. It can persist into old age on and off. Although it may never be cured, it can be managed.

• Use a good quality shampoo.
• Wash hair frequently, especially if dandruff is a problem.
• Wash hair with a dandruff treatment shampoo, lathering well and ensure lather remains in hair for 5 minutes before rinsing to ensure effectiveness.