Itching is defined as the sensation that causes the desire to scratch. It is the most common skin symptom that bothers our patients. The medical word for itch is pruritus. Itching is most often, but not always, related to the normal skin defense of histamine release. Histamine is the “itch chemical ” produced by our body to let us know something is wrong. Histamine causes redness, swelling, and itching. For example, the “welt” that develops after a mosquito bite. That is why “antihistamines” are sometimes recommended to treat itch.
Itching is not always due to an allergy. Dry skin, skin product ingredients, friction (like scratching!) can trigger itch. Some skin conditions are extremely itchy, and can make a patient have sleepless nights! Examples of itchy skin problems are atopic eczema, contact dermatitis (like poison ivy), chicken pox, “hives” (urticaria), and scabies. Usually the provider can identify the pattern of a rash to make a specific diagnosis of what kind of itchy rash a patient has.
Itching when there are no visible rashes or spots is a lot trickier to figure out. Medications or internal problems ( like thyroid, kidney or liver disease) can cause generalized itching. Sometimes there is a skin problem that is hard to see, so the dermatologists are a good resource to help figure out itching even if there is no obvious rash.