When a person has an itch that lasts more than six weeks it should be examined by a doctor, because chronic itching can drastically impair the life of the person affected, according to a Health Services Research, Dermatology centre in Hamburg.

The itch can cause not only difficulty in sleeping and therefore impairing the affected person’s productivity, but also can result in open sores that can become infected. In addition the itching can also affect the sufferer’s psyche: Many patients become depressed and close themselves off, which can lead to an inability to work.

The most common causes of pruritus - the medical term for itching - or accompanying illness associated with it are neurodermatitis, psoriasis, contact eczema, dry skin, metabolic dysfunction and neurological problems, a pruritus centre at the university clinic in Muenster, Germany said. In some cases a blood test or X-ray are necessary to make a diagnosis and in others patients must be checked into a clinic for treatment.

A study of employees released recently by the two centres showed that about 17 per cent of those surveyed suffer from bothersome itching. Almost 12,000 employees between the ages of 16 and 70 at 144 companies in various types of businesses participated in the survey.

About 4 per cent described their itching as severe or constant. The older the person, the more common itching becomes, according to the survey. About one-quarter of the people asked replied that they had suffered from itching for more than five years.

However, only about half consulted a doctor or pharmacist about their condition. Ninety-four per cent refused outright to undergo therapy.