Swimmer’s Dermatitis


July 7, 2017 by Agnes Usoro

By: Agnes Usoro

Review Question

Patient arrives in your ED with an erythematous papular rash after swimming in a pond, lake or river. What do you do?


  1. Quickly step out of the room and put on a haz-mat suit (Whatever they have, I don’t want it!)
  2. Grab your pocket razor and perform a shave biopsy (your inner Dermatologist has been dying to come out)
  3. Remember that Daily Bolus of LR post talking about this very topic

Answer: C (and of course, I’m probably doing A as well)


  • There are various pathogens that can cause skin manifestation of infection after submersion within a body of water. Common associations include:
    • Freshwater – Cercarial Dermatitis
    • Saltwater – Seabather’s Eruption
    • Hot Tub – Pseudomonas Folliculitis
    • Underwater Activities – Staph Folliculitis
  • Regardless of their exposure to water, always consider Secondary Syphilis, which is The Great Imitator

Cercarial Dermatitis (Swimmer’s Itch)

  • Pruritic, erythematous papular / maculopapular rash on “exposed” areas
  • Caused by an allergic reaction to skin penetration of Schistosomiasis (various species)
  • Suspect in patient with recent travel to Africa, Caribbean, Brazil, Middle East or SE Asia
    • S.mansoni – Africa, Caribbean, Brazil, Middle East
    • S.haematobium – Africa, Middle East
    • S.japonicum – China, Philippines
    • S.mekongi – Laos, Cambodia
    • S.intercalatum – Africa
  • Diagnosis: Clinical
    • Travel History with swimming in fresh water
    • CBC with eosinophilia
    • Serum or Urine ELISA
    • Peripheral blood smear and Stool O&P not helpful at this stage of infection
  • Treatment:
    • Praziquantel 20mg/kg TID x1 day (or 60mg/kg x1 dose) + Repeat in 1 month
    • Antihistamines
    • Topical Steroids
    • Bathe in Oatmeal bath (Aveeno), Epsom salt or Baking soda
    • Anti-itch lotions (Baking soda paste, Calamine lotion)
  • Pearl:
    • If the patient has an associated urticarial rash, along with constitutional symptoms (fever, chills, fatigue), consider Katayama Fever = an acute serum sickness reaction to Schistosomiasis

Sea Bather’s Eruption

  • Extremely pruritic, erythematous papular / maculopapular rash on “unexposed” areas (women are more at risk as these microscopic parasites get trapped in their bathing suits)
  • Caused by direct stingers of sea lice, sea anemones or jelly fish polyps
  • Suspect in patient with recent travel to the East Florida, Bermuda or the Caribbeans
  • Diagnosis: Clinical
    • Travel History with swimming in sea water
  • Treatment:
    • Cold water + an Acid (Vinegar) -> release of the nematocyst stingers
      • Do NOT use human urine or alcohol!
    • Antihistamines
    • Topical Steroids
    • Anti-itch lotions (Baking soda paste, Calamine lotion)


  • Pruritic, erythematous papular / maculopapular / pustular rash with a central hair
  • Suspect in a patient with travels to exotic islands where ocean activities are common or anywhere with recent public (swimming pool, hot tub) water use
  • Caused by localized bacterial infection of the hair follicle
    • Staphylococcus aureus (Bockhart Impetigo) – prolonged wear of a wet suit
    • Pseudomonas aeruginosa – Exposure to hot tub, poorly chlorinated swimming pool or whirlpool
  • Diagnosis: Clinical
  • Treatment:
    • Topical antibiotic cream (Mupirocin, Clindamycin, or Erythromycin)
    • Antihistamines
    • Topical Steroids

Secondary Syphilis

  • Mildly pruritic, erythematous maculopapular rash that usually starts on the trunk and spreads to the limbs, involving the palms and soles
  • NOT associated with water exposure, but should be suspected in anyone with a maculopapular rash involving the palms and soles. Their sexual activities during  a recent travel expedition should be taken into consideration.
  • Caused by infection with Treponema pallidum bacteria
  • Be aware that many people are not aware of the chancre of Primary Syphilis
  • Only 25% of infected individuals develop the systemic illness of Secondary Syphilis. The majority of individuals progress to Latent Syphilis
  • Diagnosis:
    • Screening Tests: Serum RPR or VDRL
    • Confirmation Tests: Serum FTA-ABS or MHA-TP
  • Treatment:
    • Penicillin G Benzathine 2.4 million units IM x1


— Image obtained from Hamdi, KA., Malikey, MA. Frequency of skin diseases among sea fishermen in Basrah. The Internet Journal of Dermatology. 2008. Volume 7, Number 1. DOI: 10.5580/16f6

— Freedman, DO., et al. 2006. Geosentinal Skin Problems. N Eng J Med; 354:119-130

— White, CA. 2016 Tropical Medicine Course, UTMB School of Medicine

One thought on “Swimmer’s Dermatitis

  1. Jonathan Cohen says:

    Thank you for a very helpful review.Well done!


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