Differential Diagnosis for Papular Rash after Swimming at Beach
- Single most likely diagnosis
- Seabather's eruption: This is the most likely diagnosis due to the temporal relationship between swimming at the beach and the development of a papular rash. Seabather's eruption is caused by the sting of certain marine organisms, such as jellyfish or sea anemones, and typically presents as a pruritic, papular rash.
- Other Likely diagnoses
- Swimmer's itch: Also known as cercarial dermatitis, this condition is caused by an allergic reaction to the larvae of certain parasites found in contaminated water. It presents as a pruritic, papular rash and is a common issue for people swimming in freshwater or saltwater.
- Contact dermatitis: This is a possible diagnosis if the patient came into contact with an irritant or allergen while swimming, such as certain types of seaweed or soap.
- Insect bites: Mosquitoes, sand flies, or other insects found near beaches can cause papular rashes due to bites.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Stingray sting: While less common, a stingray sting can cause a severe reaction, including a rash, and can be life-threatening if not treated promptly.
- Portuguese man-of-war sting: The venom from a Portuguese man-of-war sting can cause a severe systemic reaction, including a rash, and can be deadly if not treated promptly.
- Rare diagnoses
- Aquagenic pruritus: A rare condition characterized by intense itching after exposure to water, which can sometimes present as a papular rash.
- Erythema multiforme: A rare skin condition that can be triggered by various factors, including infections or medications, and presents as a target-like rash. While not directly related to swimming, it could be considered in the differential diagnosis if other symptoms are present.