Causes of Itchy, Red Rash

Content provided by the Faculty of the Harvard Medical School

Causes of Itchy, Red Rash

Question:

I get itchy rashes on my belly, arms, and legs. They look like mosquito bites at first, but after some time, the itch becomes less intense, and the color turns dark, leaving little dark dots on my skin. Sometimes a bit of fluid comes out of them. I have tried different kinds of medicines and ointments, but they never really solve the problem. What can these rashes possibly be? What can I do to get rid of them?

Answer:

An itchy rash that looks like mosquito bites could be caused by a number of things, including bites by mosquitoes, gnats, fleas, mites, lice, bedbugs, and many other creatures. Whenever skin is irritated by bites of any kind, itchy red bumps can develop. If you scratch the tops off such bumps, a small amount of fluid may come out. The bumps will gradually fade, leaving tiny dark spots that last a while before fading completely. The dark color left behind after the redness has gone is called "post-inflammatory hyperpigmentation." This is a common occurrence after any skin irritation.

Scratching opens the skin to potential infection, so treating the itch is important. Your doctor can prescribe topical creams and oral antihistamines to control itching. If mosquitoes or gnats are the culprits, insect sprays and wearing clothes to cover your skin can help prevent bites. If fleas or mites are the problem and you have a pet, be sure to have your pet checked and treated.

One troublesome mite that be transmitted from human to human and sometimes from pets to humans is called scabies. This mite, which causes severe itching, can burrow into the skin and lay eggs, resulting in more and more mites. Your doctor can scrape your skin and examine the scrapings under a microscope to see if you have this kind of mite. If so, a prescription cream can rid you of this itchy pest.

Because there are so many causes of itchy red bumps, including conditions not caused by bites, it is important to see your doctor for diagnosis and treatment if the problem persists.

Last updated:	April 24, 2009