Pruritus is defined as any itching or tingling sensation on the skin that provokes the desire to scratch or rub. It may appear either all over the body (generalized) or may be limited to specific areas of the body (localized).

In many cases, the cause of an itch is complicated and difficult to diagnose. It may result from an associated skin disease, such as chicken pox, hives or eczema, or a skin rash. In other cases, an internal disease such as parasite infestation or kidney or liver failure may cause pruritus.

Most cases of pruritus can be treated at home and do not require professional treatment. However, pruritus that is severe, prolonged or cannot be explained requires a visit to a physician. In most patients, pruritus responds well to treatment.

Pruritus is the medical term used to describe an itching or tingling sensation on the skin that provokes the desire to scratch or rub. In some cases, pruritus may be a minor but persistent nuisance for patients. In other instances, it can cause major discomfort, frustration and even potential health risks for the patient.

Pruritus may occur either all over the body (generalized) or may be limited to specific areas of the body (localized). Pruritus is experienced subjectively, is not precisely defined, and can be associated with a variety of medical conditions. Pruritus may affect people in any age group, but it is especially prevalent in older people, who are more likely to have dry skin (xerosis) than other members of the population.

The itch impulse travels in the body along the same pathways as pain impulses, from the nerves on the surface of the body to the brain. The normal response to the itch sensation is scratching. Scratching can relieve an itch for 15 to 25 minutes, but it can also worsen itchiness by creating a cycle of itching and scratching. In addition, persistent scratching may produce the following:

• Redness
• Irritation
• Fissures (cracks in the skin)
• Lichenification (thickening of the skin)
• Infection
• Other undesirable side effects

Most cases of pruritus can be treated at home and do not require professional treatment. However, pruritus that is severe, prolonged or cannot be explained requires a visit to a physician. Medical care should also be sought if pruritus is associated with loss of sleep, anxiety, depression or unexplained symptoms.

In order to determine the cause of pruritus, a physician will perform a complete physical examination and compile a thorough medical history. While collecting the patient’s medical history, the physician will ask detailed questions regarding the characteristics of the pruritus, including the time of onset, the extent (generalized or localized), the severity, the quality (e.g., burning sensation, pricking sensation), the duration, and diurnal and seasonal variations (e.g., worse at night or in the winter).

The physician will also attempt to determine any aggravating factors (e.g., bathing, exercise, clothing). Questions regarding the patient’s daily activities, health, hobbies, workplace responsibilities and use of medications and cosmetics can also help the physician pinpoint the underlying cause.

In many cases, a visual examination of the skin is sufficient to diagnose the cause of pruritus. However, a blood test or biopsy may be necessary to confirm a diagnosis in some cases. Diagnosis is also sometimes complicated by the fact that excessive scratching and rubbing can obscure features usually used to diagnose a type of rash or other skin disorder.

Sometimes the cause of an itch is obvious, such as an insect bite. However, in many cases, the cause of an itch is complicated and difficult to diagnose. Itching occurs when the nerves in the skin react to the release of chemicals such as histamine. The signals from these nerves are processed in the brain and perceived as itching.

Pruritus often results from an associated skin disease, such as chickenpox, hives, lichen planus, psoriasis or eczema. Skin infections and skin rashes are also common triggers. In some cases, itching results from dry skin (xerosis). Dry skin can be caused by atmospheric conditions (e.g., lack of humidity, cold air), aging or another source. Certain medications (e.g., hormones, narcotic pain relievers) and foods can also cause skin reactions that lead to pruritus. Pregnancy causes hormonal changes that may result in itching as well. This typically occurs in the second and third trimesters of pregnancy, and quickly subsides after delivery.

Internal diseases can also cause pruritus. Infestations of the skin with a parasite – such as in the case of scabies or head lice – may cause itching. When pigmented moles itch, they should be checked to ensure that the mole has not become cancerous. Other internal conditions that may cause pruritus include:

• Allergic reactions
  
  
• Shingles
  
  
• Blood disorders, such as anemia, polycythemia vera and multiple myeloma
  
  
• Kidney failure
  
  
• Liver disease, including hepatitis C and primary biliary cirrhosis
  
  
• Neurologic conditions, such as pinched nerves and strokes
  
  
• Thyroid disease, including both excessively high or excessively low thyroid hormone levels
  
  
• Cancers, such as adenocarcinomas, squamous cell carcinomas and Hodgkin’s disease

Other diseases, such as AIDS and diabetes, can also cause pruritus. Pruritus may also occur due to faulty processing of the itch sensation within the nervous system. In rare cases, pruritus is psychogenic (something that is mental or emotional rather than physiological in origin).

Treatment for pruritus will vary depending on the source of the itching. Treating underlying skin diseases such as hives or eczema usually relieves any associated itch. Itchiness resulting from an internal disease may require oral medications or other therapies that treat the underlying disease, thereby eliminating the itch. In some cases, prescription medications such as oral or topical corticosteroids, antihistamines, antidepressants and tranquilizers may be used to relieve itching.

Phototherapy may also be recommended. This form of treatment, which involves controlled exposure to ultraviolet radiation, is particularly useful for pruritus associated with diabetes, liver disorders and kidney problems, as well as those without an identifiable cause.  

Regardless of the cause of pruritus, there are also several measures that may be taken to relieve symptoms. These include:

• Avoid taking hot baths or showers. Instead, bathe in tepid or lukewarm water to avoid drying out the skin.
  
  
• Limit bathing time. Showers and baths should be limited to 10 minutes or less, especially if the patient has dry skin.
  
  
• Keep cool. Wear light clothing. Try to remain in cool environments at work and at home while avoiding excessive heat and humidity.
  
  
• Wear loose-fitting clothing.
  
  
• Avoid clothing made of rough or irritating fabric (e.g., wool, linen). Instead, choose natural fabrics such as cotton and silk.
  
  
• Apply cool compresses to itchy areas.
  
  
• Use mild soaps. Perfumed soaps often cause irritation and dryness of the skin. Use soap only in areas where odor is an issue (e.g., underarms, groin). After bathing, completely rinse off the soap film, pat the skin lightly with a towel and apply moisturizing lotion or cream while the skin is still damp.
  
  
• Use home-based treatments to alleviate symptoms. Topical drying agents such as calamine lotion, or oatmeal or cornstarch baths can help treat itchy conditions where blistering or weeping of the skin is present, such as chickenpox or poison ivy. Over-the-counter oral antihistamines and corticosteroid creams can provide some relief as well. Medications should not be used without first consulting a physician. Patients may also benefit from the use of a humidifier.
  

  

• Adequate nutrition and water consumption. A healthy diet contributes to healthy skin. A diet with a balance of proteins, carbohydrates, fats, vitamins, minerals and fluids will help maintain the skin as a protective barrier.
  
  
• Keep fingernails short to avoid damage to the skin from scratching.

It is important to seek medical treatment for pruritus that is persistent or severe. Excessive scratching or itching of the skin can result in secondary infections. In most patients, pruritus responds well to treatment.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following pruritus-related questions:

1. What may be causing my pruritus?
   
   
2. What methods will you use to determine the underlying cause of my pruritus?
   
   
3. Are there any medications available to help relieve my symptoms?
   
   
4. Are there any home remedies I can use to help relieve the itchiness?
   
   
5. When can I expect the itchiness to subside?
   
   
6. How can I help prevent pruritus flare-ups?
   
   
7. What steps can I take to prevent infection?
   
   
8. When should I seek medical attention for pruritus?