Swimmer's itch

Definition
Swimmer's itch, technically referred to as schistosome cercarial dermatitis, is a skin condition that can develop after contact with certain bird or animal parasites (organisms that invade the body and live either on or in it) in bodies of water.

Causes/associated factors
Swimmer's itch is caused by a parasite found in the waste and droppings of infected birds and animals, such as ducks and muskrats. The parasites invade snails and mature. Then, they're released into the water, where they're able to infect humans. As you wade or swim through the affected water, the parasites can attach themselves to your uncovered skin. Next, the parasites burrow under your skin and die, causing irritation and inflammation.
In the United States, swimmer's itch is most common in the Great Lakes region. Although the parasite that causes swimmer's itch is found mainly in freshwater, saltwater exposures are possible. When the condition develops after exposure to saltwater, it's called clam digger's itch. Less commonly, clam digger's itch occurs after exposure to coastal waters. Unlike swimmer's itch, clam digger's itch generally affects covered areas of the body.


Transmission
You may catch swimmer's itch by wading or swimming in water that contains the offending parasite.

Signs/symptoms
After the first exposure to contaminated water, symptoms are typically mild. If you wade or swim in the water again, you may experience a burning and itching sensation within hours after leaving the water. This can happen to any body part exposed to the contaminated water. Small, reddish, itchy bumps that may resemble mosquito bites usually develop as well.

Diagnosis
Swimmer's itch can easily be mistaken for other diseases, making diagnosis difficult. It's important to know if swimmer's itch is prevalent in the swimming water in your area.

Treatment
Typically, the itching stops and the areas begin to heal in about a week. Treatment focuses on alleviating symptoms. Because affected areas can easily become infected, do not scratch the rash. To control itching, your doctor may suggest over-the-counter antihistamines, cool compresses, or oatmeal or baking soda baths. For severe inflammation, you may need a topical steroid ointment or other anti-itch creams. Oral steroids (taken by mouth) may also be prescribed.

Complications
A secondary infection may develop in the affected area, particularly if scratching is severe. In this case, oral antibiotics may be needed.

Pregnancy-specific information
Pregnancy is not a risk factor for swimmer's itch.

Senior-specific information
Growing older is not a risk factor for swimmer's itch.

Prevention
To prevent swimmer's itch, avoid swimming in water known to be contaminated with the offending parasite. Avoid marshy areas where snails are commonly found. If you must be in the water, protect yourself with a full-body swimming suit or wet suit. If only your lower legs will be exposed, rubber wading boots are sufficient. It also helps to briskly rub down your body with a coarse towel right after coming out of the water and wash the exposed areas with soap.