Itchy scalp conditions and solutions

An itchy scalp is a common and annoying problem that is often accompanied by visible white flakes (dandruff) and occasional soreness. Dr Sarah Brewer investigates.

The skin on your scalp is made of normal skin cells that are continually replaced like skin elsewhere on the body. Dead cells that fall off are usually washed or brushed away without any problem. If the cells are replaced at a faster rate, or if the scalp is excessively dry, greasy or inflamed, however, dead cells may clump together to form larger, visible flakes which often itch.

Seborrhoea

The most common cause of itchy scalp with flaking is a hypersensitivity to the skin yeast, Pityrosporum ovale, which lives on everyone's scalp. When yeast cell numbers are low, few problems occur. When their numbers increase, however, they can trigger a low-grade inflammatory reaction with itching and excessive flakiness - a condition known as pityriasis capitis.

If a more severe inflammatory response occurs, with redness and the formation of large dry, or greasy scales, it is known as seborrhoeic dermatitis. This reaction often spreads to involve the ears, eyebrows, nose and chest as well as the scalp. In severe cases, yellow crusts may form, especially around the hairline - for example in cradle cap which often affects newborn babies. Seborrhoeic dermatitis seems to be most common in young, adult males, and may also cause inflammation of the eyelids (blepharitis).

Treatment involves using an anti-fungal shampoo containing ketoconazole, which reduces flaking and helps to control the number of yeast cells present. If scales are stuck to the scalp, you can usually loosen them by gently rubbing a simple baby oil or olive oil into the affected area, and leaving it overnight - wear a cap to protect your pillow cases - and then wash off the following day along with the loosened crusts. After a few treatments, most seborrhoeic scales should have been removed. Brushing the hair with a clean soft-bristled brush will also help. For a natural approach, try rubbing your scalp with a solution of 7 drops Tea Tree and 7 drops lavender essential oil, diluted with 1 tablespoon (15 ml) carrier oil before washing your hair.

Inflammation in seborrhoeic dermatitis is sometimes linked with lack of essential fatty acids, and it is a good idea to take regular evening primrose, and omega-3 fish oils supplements, as well as eating more oily fish, nuts, seeds and wholegrains. Cut back on your intake of processed foods.

Psoriasis

Scalp psoriasis occurs when skin cells on the scalp are produced more quickly than normal. These new cells push up to the surface to form a raised red area known as a plaque. The old skin cells build up on the surface of the plaque to form fine, silvery scales with underlying redness. It often involves the hairline and may also affect your forehead, behind your ears and the back of your neck. Scalp psoriasis tends to occur after the age of 30 years, but can appear at any time. The skin abnormality means that people with psoriasis can also suffer from other scaly scalp problems including seborrhoea, and they can be difficult to tell apart.

Treatment involves shampoos containing coal tar extracts, salicylic acid or anti-psoriasis drugs such as calcipotriol, as advised by your doctor.

Head lice

Itchy scalp can also be due to head lice (Pediculus humanus capitis) which have been described as mechanised dandruff. These small, blood-sucking, wingless insects can infest anyone of any age, usually passing from head to head during direct hair-to-hair contact. Combing can build up enough static electricity to eject an adult louse more than a metre away from the scalp, however, while young nymphs are light enough to be blown around in the air. Lice can also crawl on pillows and towels.

The average infestation consists of 10 - 20 adult head lice plus hundreds of eggs. If left untreated, as many as 5000 lice may hatch out within three months. Lice feed on human blood around five times per day, during which they produce small amounts of saliva. This can trigger a hypersensitivity reaction to cause itching ? but not until 4 to 6 weeks after infestation. Only one in three people develop this symptom, so don?t assume someone is not infested just because they don't itch. When itching and scratching do occur, symptoms are usually worse behind the ears and at the back of the neck. You may also notice tiny, red, inflamed bites on the scalp or a rash on the back of the neck or behind the ears.

Treatment involves wet combing with lots of slippery conditioner, dry combing with electrified combs, insecticide shampoos (eg pyrethrins, malathion), natural repellents such as Neem seed and tea tree oils, and coconut derivatives which block lice air passages so they cannot 'breathe'.

Best advice

If itchy scalp does not clear within two weeks of using a home treatment, always consult your doctor as you may need a treatment that is only available on prescription.