Itch (Itching or Pruritus)
What facts should I know about itching?
- The medical term for itching is pruritus.
- Bacterial and fungal infections, bites and stings, infestations, chronic diseases, atopic dermatitis, psoriasis, allergic reactions, sun exposure, and dry skin, and other skin disorders and health conditions all may be causes of itching.
- Anti-itch creams and lotions containing camphor, menthol, phenol, pramoxine (Caladryl, Tronolane), diphenhydramine (Benadryl), or benzocaine can bring relief.
- Some cases of itching will respond to corticosteroid medications.
- It is important to avoid scratching when possible to prevent worsening of the condition and disruption of the skin that could lead to bacterial infection.
- If itching persists, worsens, or is associated with skin lesions, go see a health care professional.
What is an itch?
Itch is an irritation in the skin that elicits an urge to scratch. Itchiness is a problem that everyone experiences, and the symptom can be localized (limited to one area of the body) or generalized (occurring all over the body or in several different areas). Sometimes, depending upon the underlying cause, itching may be worse at night. In medical terminology, itching is known as pruritus.
Generalized itch that occurs all over the body is often more difficult to treat than localized itch. Itches can also occur with or without skin lesions (bumps, blisters, rash, redness, or abnormalities that can be seen on the skin). An itch that is accompanied by a visible skin abnormality should be evaluated by a physician and, in some cases, by a dermatologist since the problem is likely to be a condition that requires specialized medical treatment (for example, eczema, scabies, etc.).
What are associated symptoms and signs of itching (pruritus)?
Depending upon the underlying cause, itchiness may be associated with other symptoms and signs. Most commonly, these associated findings include skin lesions such as rash, blisters, bumps, or redness of the affected area. Dryness of the skin is a common cause of itch. Itching of skin can lead to tears in the skin (excoriations) from scratching. Less commonly, generalized itching all over the body can be a sign of chronic medical conditions such as liver disease. In these situations, there may be no changes to the appearance of the skin.
What causes itching?
Pruritus can be caused by many conditions. Stress, anxiety, or other emotional problems can cause itching. Stress also can aggravate itch from other causes. Dry skin (xerosis) is perhaps the most frequent cause of itch without a rash. Many people also report sunburn itch following prolonged exposure to UV radiation from the sun along with the pain of sunburn. Other causes of generalized itching that may not produce a rash or specific skin changes include metabolic and hormone disorders (for examples, kidney disease, hyperthyroidism), cancers (for example, lymphoma), reactions to drugs, interruptions in bile flow (cholestasis) from liver disease, and diseases of the blood (for example, polycythemia rubra vera). Itching is common with allergic reactions, such as food allergies or other types of allergy. Itching can also result from insect stings and bites such as mosquito or flea bites.
Psoriasis is a chronic cause of skin inflammation that can also be associated with itching. Patients with psoriasis typically develop red, elevated, scaling plaques of dry, itchy skin. Atopic dermatitis is a chronic inflammatory disease of the skin that usually starts in childhood. Itching, rash, and thickening of the skin over time are characteristic symptoms of atopic dermatitis. This is considered to be a type of allergy (an immune system reaction against a foreign substance) that is associated with inhaled allergies (hay fever) and is chronic.
Infections and infestations of the skin are another cause of itch. Genital itching or anal itching, which may accompany burning and pain, in men and women can occur as a result of genital infections such as sexually transmitted diseases (STDs). Vaginal itching is sometimes referred to as feminine itching, and sexually transmitted diseases can also cause anal itching and pain. Vaginal yeast infections are another cause of vaginal itching. Other common infectious causes of itch include a yeast (fungal) infection of the crotch (tinea cruris) commonly known as jock itch, psoriasis, and ringworm of the body (tinea corporis). Another type of parasitic infection resulting in an itchy sensation is the so-called swimmer's itch. Swimmer's itch, also called cercarial dermatitis, is a skin rash caused by an allergic reaction to infection with certain parasites of birds and mammals that are released from infected snails in fresh and saltwater. Itch may also result from skin infestation by body lice, including head lice and pubic lice. Scabies is a highly contagious skin condition caused by an infestation by the itch mite Sarcoptes scabiei that is known to cause an intense itch that is particularly severe at night.
What causes itching? (Continued)
Brachioradial pruritus is a neurologic condition that results in intense itching of the arms. It usually develops on the forearm over the head of the brachioradialis muscle, but it can occur anywhere on the upper extremities. This is often caused by a pinched nerve in the neck.
Itching can also result from other conditions that affect the nerves or nervous system, such as diabetes, shingles (herpes zoster), or multiple sclerosis.
Irritation of the skin from contact with fabrics, cosmetics, or other substances can lead to itching that may be accompanied by rash, known as contact dermatitis. Poison ivy is another example of contact dermatitis. Reactions to drugs or medications can also result in widespread itching that may be accompanied by a rash or hives. Sometimes women report that they experience generalized itching during pregnancy or a worsening of the conditions that normally cause itching. Contact dermatitis from poison ivy, poison oak, or poison sumac (due to contact with the oily sap urushiol) or allergy to nickel are also common causes of localized itching.
Itching of the scalp can be caused by a number of conditions, including dandruff, psoriasis, or seborrheic dermatitis.
Most people who have itching do not have a serious underlying condition.
How do health care professionals diagnose itching?
As with any condition, a careful medical history and physical examination will suggest to your health care provider the particular diagnostic tests that may be needed to learn the cause of itching. Some common causes like dry skin or sunburn may be obvious, while causes such as chronic systemic diseases or conditions may require blood or imaging tests to identify. If a skin condition is responsible for the itch, sometimes a scraping or biopsy may be performed to identify the condition. Nevertheless, many common rashes and skin ailments have a characteristic symptom or appearance that may suggest the correct diagnosis.
What types of health care specialists treat itching?
Because the causes of pruritic skin are so varied, many different medical practitioners can be involved in treating itching. Itching is commonly treated by specialists in family medicine, internal medicine, pediatrics, or dermatology. Itching related to allergy may be treated by an allergist or immunologist. Itching related to STDs may be managed by a gynecologist or urologist. An obstetrician-gynecologist may treat women suffering from itching during pregnancy or vaginitis. People with itching due to chronic diseases may be treated by the specialists who manage these conditions, such as endocrinologists, gastroenterologists, nephrologists, oncologists, hematologists, neurologists, and infectious-disease specialists. Some causes of itching are treated by emergency-medicine specialists.
