Try coal tar soap to help cure that itch

QFOR four months I have been suffering from an itchy scalp. There are no visible blemishes, but it is very irritating. The chemist suggested using a special shampoo, but so far it has not helped for more than one or two hours after washing. I am 79.

AArchibald Law, Glasgow. The likely diagnosis is seborrhoeic dermatitis at an early stage. If the condition progresses, you may observe redness and scaling across the scalp — known as dandruff.

The root cause is unknown, but it is thought that a reaction between the skin and a yeast that can grow there produces toxic substances that irritate the scalp.

Stress, fatigue, alterations in general health — even seasonal changes can play a role.

Seborrhoeic dermatitis affects up to 5 per cent of the UK population, is slightly more common in men and, while it may come and go throughout life, it’s definitely more common in your age group.

Your local chemist wisely recommended a shampoo containing coal tar, which acts as an antifungal and reduces the yeast in the superficial layers of the skin, allowing the inflammation to settle.

If, after two or three months of this twice-weekly treatment, you are still plagued by itching, I would suggest you try a different shampoo that contains other antifungals.

One example is Sachajuan scalp shampoo, which has three suitable ingredients: piroctone olamine, climbazole, and salicylic acid.

This must be used twice weekly for the first month, and then once weekly thereafter . You should discuss this option with your chemist.