Why Does Itching Occur?
Itching and pain are closely-related sensations because the same nerves transmit both types of sensory signals to the brain. When the area of skin is scratched, that same area may become even itchier, leading to more scratching. This is called the itch-scratch cycle.
In general, itching can be related to a skin condition or to an underlying systemic (throughout the body) disease. A systemic disease doesn’t usually cause itching in just one area of the skin.
What Causes Itching?
The causes of itching can be divided into localized and generalized.
Localized itching on just one part of the body is likely to be caused by a skin condition. The area of the body that itches may give a clue as to the cause of the itch. For example, itching of the scalp is most likely due to seborrheic dermatitis (dandruff), atopic dermatitis, contact dermatitis, psoriasis, or head lice.
Generalized itching may be due to a skin condition or a systemic disease. Skin conditions that cause itching all over the body include hives, atopic dermatitis, and contact dermatitis.
Itching may also be caused by systemic problems, such as medications (such as narcotics and other pain medications), infections (such as parasitic infections of the intestines), iron deficiency, liver disease, kidney disease, high or low thyroid function, as well as certain cancers.
What Common Skin Allergies Cause Itching?
There are three common allergic skin conditions that cause itching. These include atopic dermatitis (eczema), hives (urticaria), and contact dermatitis.
Atopic dermatitis usually affects children and young adults, and causes itching of the skin, especially in the flexural (inner) areas of the elbow folds and behind the knees. Scratching the skin results in a dry, flaky rash that may be associated with blisters and oozing. Hives is an itchy rash that can occur at any age, but commonly affects children. This rash appears as raised red bumps of various shapes and sizes that typically last for only a few minutes to a few hours. In about 40% of people with hives, skin swelling around the eyes, mouth, tongue, or hands/feet may occur, which is called angioedema. Contact dermatitis is caused by skin contact with a chemical that results in a rash that looks like poison oak or poison ivy. Plants of the Toxicodendron family are a common cause of plant-induced contact dermatitis, resulting in an extremely itchy rash that has blisters that ooze and crust. People can also react to a variety of other chemicals, including cosmetics/make-up, sunblock, hair dye, metals, topical medications, and dental materials.
What is the Treatment For Itching?
If the cause of the itching is identified and if it can be avoided or corrected, then the itching can be cured. However, this is not always possible. Treatment of the itching depends on the cause, and some general measures would apply to most cases of itching.
Treatment of dry skin as the cause of itching: Many people with dry skin have a difficult time finding relief. Various skin treatments, including over-the-counter moisturizers and prescription steroid creams, may not be effective alone. A technique called “soak and slather” has long been used successfully to treat dry skin.
This technique involves soaking in a warm, plain water bath followed immediately by the application of a fragrance-free cream or ointment to seal the moisture from the recent bath. If this is insufficient to control symptoms, a similar technique can be employed with topical corticosteroids to affected skin areas, using plain moisturizer or ointment on the skin without rash.
Creams for the treatment of itching: Topical steroids are anti-inflammatory medications used to treat various skin conditions. These medications can reduce inflammation, itching, flaking, and oozing when applied to the skin one or more times a day. There are a number of types of topical steroids available by prescription, as well as hydrocortisone 1% cream, which is available over the counter without a prescription.
Facial creams for itching: Only certain types of anti-itch creams can be used on the face. The skin on the face is particularly susceptible to the side effects of topical steroids, and getting these medications into the eyes can result in glaucoma or cataract formation.
Therefore, only the lowest-potency topical steroid that is required to treat symptoms should be used on the face and only for the shortest amount of time possible.
Antihistamines for the treatment of itching: Certain forms of itching, particularly hives, may respond to treatment with oral antihistamines. Non-sedating antihistamines, such as Zyrtec (cetirizine) and Allegra (fexofenadine) are generally preferred over sedating antihistamines because they pose less risk of side effects and overdose.
Other causes of itching, such as eczema and contact dermatitis, may not get better with antihistamines. There are many choices of antihistamines, including prescription-only forms and over-the-counter types.
A Word From Verywell
Itching is not usually a cause for concern, and localized itching often improves by avoiding contact with the irritating substance. Unexplained itching should be evaluated by a healthcare provider. And if the itch is impairing your sleep, you should seek further medical evaluation.
