Visual Characteristics of Swimmer's Itch
Swimmer's itch presents as an itchy maculopapular rash that appears on areas of skin exposed to water containing cercariae (larvae) of schistosome parasites. 1, 2
Key Visual Features
Initial presentation:
Established rash:
- Maculopapular eruption (flat spots with raised bumps)
- May become urticarial (hive-like) with repeated exposures 3
- Can develop vesicles (small fluid-filled blisters) in heavy or repeated exposures 3
- Primarily affects exposed skin areas that were in contact with water 2
- Does not typically affect areas covered by swimwear
Distribution pattern:
- Localized to areas of skin exposed to water
- Often more prominent on legs, arms, and trunk
- Spares areas covered by bathing suits
Progression and Duration
- Rash typically develops within hours of water exposure
- Peaks in intensity within 1-3 days
- Self-limiting condition that resolves spontaneously over days to weeks 1, 4
- No scarring occurs after resolution
Distinguishing Features
- Unlike seabather's eruption, swimmer's itch does not affect areas covered by swimwear
- Unlike hot tub folliculitis, swimmer's itch does not present with pustules
- Unlike contact dermatitis from aquatic plants, the distribution is not limited to areas of direct contact with vegetation 2
Warning Signs of Complications
- Development of crusting or weeping lesions may indicate secondary bacterial infection
- Increasing pain (rather than itching) suggests potential infection
- Spreading erythema or warmth around lesions requires medical attention 2
Clinical Course
The condition is self-limiting and typically resolves without treatment within 1-3 weeks 4. The rash may be more severe in individuals with repeated exposures due to allergic sensitization 5, as swimmer's itch represents an allergic reaction to the parasite.
Remember that swimmer's itch is a non-communicable condition and cannot spread from person to person 4, 5. It occurs worldwide but is more common during warm weather when people engage in water activities and when higher temperatures increase cercarial shedding from snails 6, 7.