What is the treatment for a rash on the chest after swimming in a lake?

Treatment for Rash on Chest After Swimming in Lake

The rash on your chest after swimming in a lake is most likely swimmer's itch (cercarial dermatitis), which typically resolves spontaneously over days to weeks and responds well to topical corticosteroids.

What is Swimmer's Itch?

Swimmer's itch (cercarial dermatitis) is a localized skin reaction that occurs when certain microscopic parasites (cercariae) penetrate the skin. These parasites are released from infected snails and usually infect birds, but can mistakenly enter human skin when swimming in contaminated freshwater.

• Occurs as a result of a localized subcutaneous infection by species of schistosome which usually infect birds 1
• Incubation period is typically hours after water exposure 1
• Distribution is worldwide, often occurring in outbreaks 1
• Transmission occurs through fresh water exposure during swimming, when cercariae released from snails penetrate the skin 1

Clinical Presentation

• Presents as an itchy maculopapular rash on areas exposed to water 1
• The rash typically appears within hours after swimming in contaminated freshwater 1
• Incidence of swimmer's itch has been reported as 6.8 episodes per 100 water exposure days in affected lakes 2
• Risk factors include shallow water exposure and swimming in areas with onshore winds 3

Treatment Recommendations

First-Line Treatment

• Topical corticosteroids: Apply low-potency hydrocortisone cream (1-2.5%) to affected areas up to 3-4 times daily 4
• The rash typically resolves spontaneously over days to weeks 1
• Use gentle cleansers and avoid hot water when bathing to prevent further irritation 1
• Apply alcohol-free moisturizers after bathing to maintain skin hydration 1

For Moderate to Severe Symptoms

• For significant itching, oral antihistamines such as cetirizina, loratadina (10 mg/day) or hydroxyzine (10-25 mg) may provide relief 5
• Avoid excessive scratching to prevent secondary bacterial infection 5
• If symptoms are severe or persistent beyond 2 weeks, consider seeking specialist evaluation 5

Prevention Strategies

• Avoid swimming in areas known to have high incidence of swimmer's itch 2
• Towel dry or shower immediately after leaving the water to remove parasites before they penetrate the skin 5
• Avoid shallow water and areas with onshore winds, which are associated with higher risk 3
• Limit time spent in the water, as longer exposure increases severity of episodes 3

When to Seek Further Medical Attention

• If the rash worsens or doesn't improve after 2 weeks of treatment 5
• If there are signs of secondary infection (increased pain, swelling, warmth, pus, or red streaks extending from the rash) 5
• If you develop fever or other systemic symptoms, which may indicate a different diagnosis or complication 5

Important Considerations

• Swimmer's itch is not contagious and cannot spread from person to person 1
• The condition is more common during warm weather months when more people are swimming and water temperatures are higher 6
• Climate change and increasing water temperatures may lead to increased incidence of swimmer's itch due to accelerated parasite development and transmission 6