Lake itch, more commonly known as swimmer's itch or cercarial dermatitis, occurs after swimming in shallow waters of lakes and other bodies of water. A parasitic infection caused by larvae burrowing into the top layer of skin, lake itch causes a rash and itching that subsides within a week without lasting effects. Cercaria, the immature eggs or larvae of flatworms, pass into water from infected snails after being deposited in the water in the feces of waterfowl or other aquatic animals such as beavers. Since there's no cure, remedies treat the symptoms.
Antihistamines
Cercaria larvae burrowing into the skin leave a small red mark that gradually increases in size over 24 to 30 hours, explains Hope College. The raised papules itch, sting and burn; they turn into small pimples and may blister. Oral antihistamines help reduce the inflammation, swelling and itching at the infected sites.
Topical Preparations
Directly applying anti-itch creams or pastes to the reddened areas caused by the parasite burrowing into the skin decreases the discomfort. Calamine lotion, oatmeal baths, lotions specifically made for itching and baking soda pastes all help reduce itching, states the Centers for Disease Control and Prevention. Cold compresses also help control itching.
Corticosteroids
Frequent exposure to lake itch may cause a reaction to develop more quickly and to increase in severity. While only 30 to 40 percent of the population reacts to lake itch, according to the Minnesota Department of Natural Resources, each exposure increases the chance of developing a reaction. More severe cases of lake itch may require corticosteroids--medication that reduces inflammation by suppressing the immune system, given topically, orally or via an injection--to quell the reaction.
Anribiotics
The small pimples that develop due to lake itch may blister and, if scratched, may develop a secondary local skin infection. Mild localized skin infections usually respond to topical antibiotic creams, but more extensive or serious infections may require oral antibiotics.
