Swimmer's itch typically lasts from a few days up to two weeks. The itching and rash can be quite intense and usually peak within 2 to 3 days. The rash, which appears as red spots or bumps, starts within hours of exposure to the parasite and generally fades away within 1 to 2 weeks. In some cases, especially with repeated exposures, symptoms can be more severe and may last longer, potentially up to a month. However, the condition generally resolves on its own without lasting effects.

Duration of Symptoms

• Itching and rash usually appear within 1 to 2 hours after exposure and can last up to 7 days or more.
• The rash commonly fades gradually over about 2 weeks.
• Intense itching peaks at 48 to 72 hours.
• In some cases, the rash and itchiness may persist for several weeks, especially if the affected skin is scratched or if there are repeated exposures.
• The swelling usually subsides within a week, but redness can last longer.

Additional Context

• Swimmer's itch is an allergic reaction caused by tiny parasites in freshwater (and occasionally saltwater).
• There is no permanent damage from swimmer's itch, and symptoms resolve as the body heals.
• Treatment mainly aims to relieve itching with antihistamines, corticosteroid creams, cool compresses, oatmeal baths, and other anti-itch remedies.
• Severe or prolonged symptoms should prompt a consultation with a healthcare provider.

This duration and symptom course is consistent across multiple sources including Seattle Children's Hospital, the Mayo Clinic, the Cleveland Clinic, and the CDC.