Causes and Treatment of Pruritus (Itching)
Pruritus is a Latin word for itch and describes any itching or tingling sensation on the skin that provokes the desire to scratch or rub. It may be a minor but persistent nuisance, but, in some cases, it can cause major discomfort, frustration and even pose potential health risks for the patient. Pruritus cannot be precisely defined because it is experienced subjectively.
Pruritus may be localized and limited only to specific areas of the body or it may be generalized and occur all over the body. It may affect people of any age, though it is more prevalent in older people who have dry skin. Pruritus may or may not be associated with another medical condition.
Scratching is a normal response to the itch sensation. It will temporarily relieve an itch (for 15-25 minutes), but it can also worsen the problem by creating a cycle of itching and scratching. Moreover, persistent scratching may cause further complications such as skin redness and irritation, infections, fissures and thickening of the skin.
Potential Causes of Pruritus
Itching occurs when the nerves in the skin react to the release of chemicals such as histamine. In some cases, the cause of this reaction is obvious, such as a mosquito bite. In other instances, the cause of an itch may be complicated and difficult to diagnose. However, pruritus is often a symptom of another condition or adverse reaction to food or medications, including:
- Dry skin (xerosis) caused by atmospheric conditions (e.g., lack of humidity, cold air), aging or another source
- Skin diseases, such as eczema, psoriasis, hives, chickenpox or lichen planus
- Skin infections and skin rashes
- Infestations of the skin with a parasite such as in the case of scabies or head lice
- Pregnancy (itching typically occurs in the second and third trimesters of pregnancy)
- Other internal conditions, including:
- Neurologic conditions (e.g., pinched nerves and strokes)
- Blood disorders (e.g., anemia, multiple myeloma and polycythemia vera)
- Liver disease, including hepatitis C and primary biliary cirrhosis
- Kidney failure
- Thyroid disease
- Cancers (e.g., squamous cell carcinomas, adenocarcinomas, Hodgkin’s disease)
- Certain medications, including antifungals, antibiotics, hormones or narcotic pain relievers
- Food allergies and allergic reactions to certain herbs and other substances such as wool or cosmetics
When pigmented moles itch, they should be checked by the doctor to ensure that the mole has not become cancerous. Other illnesses, such as diabetes and AIDS, can also sometimes cause itching. In rare cases, pruritus is psychogenic rather than physiological in origin.
After initial physical examination and answering the doctor’s questions, a visual inspection of the skin is usually sufficient to diagnose the cause of pruritus. However, a blood test, biopsy or a thyroid function test may sometimes be ordered to confirm a diagnosis. In some cases, diagnosis is complicated by the fact that excessive rubbing and scratching can obscure features typically needed to diagnose a type of rash or other skin disorder.
Treatment of Pruritus
Most cases of pruritus do not require professional treatment and can be treated at home. However, itching that is severe, persistent or cannot be explained warrants a visit to a doctor. Remember that excessive scratching of the itching skin can result in secondary infections. Professional help should also be sought if pruritus is associated with anxiety, depression, loss of sleep, or other unexplained symptoms.
Treatment for pruritus will depend on the cause of the itching. Treating underlying conditions with medications or other therapies is usually needed to eliminate or relieve associated itch. Sometimes, prescription medications such as antihistamines, oral or topical corticosteroids, calcineurin inhibitors, antidepressants and tranquilizers may be given to relieve itching.
Phototherapy (controlled exposure to ultraviolet radiation) may be an effective treatment for patients whose itching is associated with diabetes, kidney problems, liver disorders and those without an identifiable cause.
Several home-based treatments can be used to alleviate itching. Topical drying agents like calamine lotion, or cornstarch or oatmeal baths can help treat itchy conditions where blistering or weeping of the skin occurs. Patients may also benefit from the use of a moisturizing cream or a humidifier. Over-the-counter corticosteroid creams and oral antihistamines can provide some relief as well. However, medications should only be used after consulting a doctor.
Regardless of the cause of pruritus, certain lifestyle measures may help relieve symptoms. These include avoiding hot baths and showers and limiting bath time, using mild soaps, wearing loose-fitting and light clothing to keep cool, avoiding clothing made of rough or irritating fabric and applying cool compresses to itchy areas. People should also reduce stress, keep their fingernails short to avoid damage to the skin from scratching and drink plenty of fluids to ensure proper hydration of the skin.