What's Causing Your Itch?

Research shows that when your body is exposed to something that causes an itch, specific nerves in the spinal cord become active and fire off signals to the brain. Those signals cause the feeling of the itch. So what does scratching do? Researchers think that scratching blocks these nerve cells from sending their message, at least temporarily.

Despite what you heard as a kid, scratching a rash caused by poison ivy won't make it spread. The liquid that might ooze from your rash isn't toxin from the plant. A poison ivy rash seems like it spreads because it might develop more slowly in some areas than others. Although scratching won't make the rash spread, it's still a bad idea -- scratching can lead to infection.

When a female mosquito – only females bite -- pokes its proboscis into your skin to draw blood, it squirts in saliva that prevents the blood from clotting. Proteins in that saliva trigger a response from the immune system, which causes the swelling and itch. The reaction will linger long after the mosquito has moved on to lay its eggs -- or been swatted into oblivion.

All three "poison" plants dreaded by campers, kids, and gardeners -- poison ivy, poison oak, and poison sumac -- have the same itch-producing chemical in their sap, urushiol. About 85% of people develop an allergy to urushiol after a few exposures. If you've touched one of the plants, wash the area with hot, soapy water. Wash your clothes and shoes, too. To help control the itch, you may want to try calamine lotion or over-the-counter hydrocortisone or diphenhydramine.

This is one traditional remedy that won't help. In fact, coating sunburn with butter could make things worse by trapping heat in the skin. The same goes for petroleum jelly. To treat a sunburn, hold the burned area under cool running water for 10 to 15 minutes or until the pain eases. You can also cover the area with cold compresses.

Over-the-counter hydrocortisone or diphenhydramine creams might help too.

Whether it's an itch caused by a bug bite or sunburn, it's pruritus. Our ability to feel an itch has an evolutionary purpose: Scratching helps animals remove parasites and other irritants from their skin. The problem is that when you scratch, you inflame the skin -- and that triggers the nerve fibers that cause more itching. It's called the itch-scratch cycle, and your mother was right: Scratching will just make it worse.

 The good news is that bed bugs don't spread disease. The bad news? They can make your nights miserable and getting rid of them is not easy. Bed bugs feed on blood and leave behind small, red, itchy spots on your skin. Although their numbers dropped in the mid-20th century, bed bugs have recently made a comeback in the U.S. They can show up anywhere, even in expensive hotels. To get rid of them, you may need to use a professional pest control service.

This traditional treatment for itchy skin has good evidence behind it. Oatmeal seems to contain natural chemicals that ease inflammation. One option is to buy colloidal oatmeal, which is extracted from regular oatmeal after it's been finely ground and boiled. But sprinkling typical supermarket oatmeal in your bath will work too.

Body heat and sweat can make an itch even itchier. So if you've got a case of itchy sunburn or poison ivy, turn on a fan or air conditioner. Wear light, loose clothing. Use cold compresses or take a bath -- just make sure that the water is cool.

Histamine -- the same substance in your body that causes an allergic reaction -- can make your cut or burn itch when it starts to heal. When your skin is damaged, cells that release histamine travel to the site to repair it. Although histamine seems to speed healing, it also causes swelling and itch. With mild burns and scrapes, over-the-counter creams and gels with the antihistamine diphenhydramine can help calm the itchiness.

Researchers believe that some of the brain cells that are active when we're scratching are also active when we're watching someone else scratch. The same can happen with yawning. Reading a sentence like "Your back is covered with mosquitoes" can have the same effect. How do you stop contagious itch? Concentrate on something else.