Itching
Pruritus
Itching is a tingling or irritation of the skin that makes you want to scratch the area. Itching may occur all over the body or only in one location.
Allergic reaction can be provoked by skin contact with poison plants, chemicals and animal scratches, as well as by insect stings. Ingesting or inhaling substances like pollen, animal dander, molds and mildew, dust, nuts and shellfish, may also cause allergic reaction. Medications such as penicillin and other antibiotics are also to be taken with care, to assure an allergic reflex is not triggered.
Head lice infect the scalp and hair and can be seen at the nape of the neck and over the ears. Head lice spread easily and quickly but do not carry disease as other lice do.
The skin is the largest organ of the body. The skin and its derivatives (hair, nails, sweat and oil glands) make up the integumentary system. One of the main functions of the skin is protection. It protects the body from external factors such as bacteria, chemicals, and temperature. The skin contains secretions that can kill bacteria and the pigment melanin provides a chemical pigment defense against ultraviolet light that can damage skin cells. Another important function of the skin is body temperature regulation. When the skin is exposed to a cold temperature, the blood vessels in the dermis constrict. This allows the blood which is warm, to bypass the skin. The skin then becomes the temperature of the cold it is exposed to. Body heat is conserved since the blood vessels are not diverting heat to the skin anymore. Among its many functions the skin is an incredible organ always protecting the body from external agents.
Causes
There are many causes of itching, including:
- Aging skin
- Atopic dermatitis (eczema)
- Contact dermatitis (poison ivy or poison oak)
- Contact irritants (such as soaps, chemicals, or wool)
- Dry skin
- Hives
- Insect bites and stings
- Parasites such as pinworm, body lice, head lice, and pubic lice
- Pityriasis rosea
- Psoriasis
- Rashes (may or may not itch)
- Seborrheic dermatitis
- Sunburn
- Superficial skin infections such as folliculitis and impetigo
Generalized itching may be caused by:
- Allergic reactions
- Childhood infections (such as chickenpox or measles)
- Hepatitis
- Iron deficiency anemia
- Kidney disease
- Liver disease with jaundice
- Pregnancy
- Reactions to medicines and substances such as antibiotics (penicillin, sulfonamides), gold, griseofulvin, isoniazid, opiates, phenothiazines, or vitamin A
Hives are allergic welts on the skin. I'm Dr. Alan Greene and let's talk about hives, how they happen, and what to do about them when you do get them. Hives are usually triggered by some kind of exposure. The most common ones are to medicines and to foods. But they can be to all kinds of different things. Even cold weather will cause hives in some people. Most of the time we don't figure out what the trigger actually was. But it's worth trying to figure out if you can. Sometimes the hives can be a sign of an allergic reaction that's serious. If you have hives and also have any difficulty breathing or have wheezing, consider that something when you need urgent medical attention. Otherwise with hives, usually you can calm down the swelling and the itching with an antihistamine. Typical over-the-counter antihistamine can work well. It's even stronger if you couple it with one of the over-the-counter antacids. An H1 blocker and an H2 blocker together such as Benadryl, or diphenhydramine, and cimetidine. Taking those together is more powerful than either one alone. You can talk to your pharmacist about how to combine an H1 and H2 blocker safely. Usually with that kind of treatment, the itching will subside fairly quickly and the whole thing will last for just a few hours unless the exposure is ongoing. Sometimes though, hives will become chronic. If you have hives that are lasting for a week or more, you certainly want to be in touch with your doctor to discuss what to do with longer lasting hives.
Home Care
For itching that does not go away or is severe, see your health care provider.
In the meantime, you can take steps to help deal with the itch:
- Do not scratch or rub the itchy areas. Keep fingernails short to avoid damaging the skin from scratching. Family members or friends may be able to help by calling attention to your scratching.
- Wear cool, light, loose bedclothes. Avoid wearing rough clothing, such as wool, over an itchy area.
- Take lukewarm baths using little soap and rinse thoroughly. Try a skin-soothing oatmeal or cornstarch bath.
- Apply a soothing lotion after bathing to soften and cool the skin.
- Use moisturizer on the skin, especially in the dry winter months. Dry skin is a common cause of itching.
- Apply cold compresses to an itchy area.
- Avoid prolonged exposure to excessive heat and humidity.
- Do activities that distract you from the itching during the day and make you tired enough to sleep at night.
- Try over-the-counter oral antihistamines such as diphenhydramine (Benadryl). Be aware of possible side effects such as drowsiness.
- Try over-the-counter hydrocortisone cream on itchy areas.
When to Contact a Medical Professional
Contact your provider if you have itching that:
- Is severe
- Does not go away
- Cannot be easily explained
Also contact your provider if you have other, unexplained symptoms.
With most itching, you do not need to see a provider. Look for an obvious cause of itching at home.
It is sometimes easy for a parent to find the cause of a child's itching. Looking closely at the skin will help you identify any bites, stings, rashes, dry skin, or irritation.
Have the itching checked out as soon as possible if it keeps returning and does not have a clear cause, you have itching all over your body, or you have hives that keep returning. Unexplained itching may be a symptom of a disease that could be serious.
What to Expect at Your Office Visit
Your provider will examine you. You'll also be asked about the itching. Questions may include when it began, how long it has lasted, and whether you have it all the time or only at certain times. You may also be asked about medicines you take, whether you have allergies, or if you have been ill recently.
References
Dinulos JGH. Urticaria, angioedema, and pruritus. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 6.
Legat FJ, Weisshaar E, Fleischer AB, Bernhard JD, Cropley TG. Pruritus and dysesthesia. In: Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. Philadelphia, PA: Elsevier; 2018:chap 6.
Version Info
Last reviewed on: 7/25/2022
Reviewed by: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
