“Swimmer’s itch” is included in the differential
Other possible causes of pruritic rashes like the one our patient had (TABLE) include:
Cercarial dermatitis, also known as swimmer’s itch, is a maculopapular inflammation characterized by pain, prickling, and pruritus. It develops several hours after bathing in freshwater and is limited to exposed areas of the body. The cause of the dermatitis? The larval trematodes of Shistosoma and Trichobilharzia.5
Phytophotodermatitis is an erythematous pruritic inflammation of the skin with vesicles and bullae. The eruption, which is often hyperpigmented, occurs when an individual spends time in the sun after coming into contact with light-sensitive botanicals, such as limes.7
Infectious folliculitis is an infection of the hair follicle resulting in the formation of multiple pustules. Pseudomonas aeruginosa folliculitis, often called hot tub folliculitis, may be pruritic and tender.7
Grover’s disease is also known as transient acantholytic dermatosis and generally affects middle-aged men. It is a pruritic dermatosis of scaling papules that are distributed along the trunk and can show confluence. Although the cause is unknown, it has been linked with cases of high fever, intense exercise, and significant sun exposure.7
Table
The differential for a pruritic, erythematous maculopapular rash5,7
| Condition | Characteristics |
|---|---|
| Cercarial dermatitis | A maculopapular inflammation characterized by pain, prickling, and pruritus that develops several hours after bathing in freshwater and is limited to exposed areas of the body. |
| Phytophotodermatitis | An erythematous pruritic inflammation of the skin, with vesicles and bullae appearing with hyperpigmented streaks along the body. It occurs when an individual spends time in the sun after coming into contact with light-sensitive botanicals. |
| Infectious folliculitis | An infection of the hair follicle resulting in the formation of multiple pustules. Pseudomonas aeruginosa folliculitis is associated with hot tub use. |
| Seabather’s eruption | An erythematous pruritic papular dermatitis that develops several hours after exposure to ocean water. It is limited to areas of high friction and those covered by swimwear. |
| Grover’s disease | A pruritic dermatosis of scaling papules distributed along the trunk that mainly affects middle-aged men. Onset is associated with high fever, intense exercise, and significant sun exposure. |
Treatment usually isn’t needed
SBE usually resolves spontaneously within a week or 2.1 If treatment is necessary, start with topical corticosteroids and oral antihistamines. If this proves insufficient, move on to oral corticosteroids1 (strength of recommendation [SOR]: C). To minimize risk, swimmers should remove their bathing suits and shower as soon as possible after leaving the water4,6 (SOR: C).
Benadryl does the trick
We advised our patient to take diphenhydramine (Benadryl) and the itching went away. We also encouraged him to remove his bathing suit and shower as soon as possible after going in the ocean.
CORRESPONDENCE Blake Fagan, MD, MAHEC Family Medicine Residency Program, 118 W.T. Weaver Boulevard, Asheville, NC 28804; blake.fagan@mahec.net