A 5-year-old girl presented with a 2-day history of a widespread pruritic rash that began while the family was on vacation. The rash appeared suddenly as small pink macules and progressed to papules and pustules. Her brother had a similar-appearing but milder rash. She denied fever, chills, or constitutional symptoms. On further questioning, her father reported that she and her brother had been in a hot tub at their vacation home.
The otherwise well-appearing patient had numerous 2- to 4-mm papules and pustules with surrounding erythema scattered on her trunk, arms, and legs.
Hot tub folliculitis, also known as Pseudomonas folliculitis, was diagnosed. This community-acquired bacterial infection of the hair follicle occurs after exposure to contained, contaminated water.
The ubiquitous gram-negative bacterial organism that causes hot tub folliculitis, Pseudomonas aeruginosa, gains entry through hair follicles or via breaks in the skin. Minor trauma from wax depilation, vigorous rubbing with sponges, or shaving may facilitate the entry of organisms into the skin. Hot water, prolonged water exposure, excessive numbers of bathers, and inadequate pool or hot tub care are all associated with outbreaks of hot tub folliculitis.
Hot tub folliculitis is characterized by the onset of a rash usually 48 hours after exposure to contaminated water; however, it can occur as long as 14 days after exposure. Lesions begin as pruritic, erythematous macules that progress to papules and pustules. The rash usually clears spontaneously within 2 to 10 days, rarely recurs, and heals without scarring.
The differential diagnosis includes acne, bromide sensitivity, staphylococcal folliculitis, and gram-negative folliculitis—an uncommon complication of prolonged antibiotic use in patients with acne and associated with Klebsiella, Escherichia, Serratia, and Proteus species. The diagnosis of hot tub folliculitis is usually made after a thorough history and physical examination. However, it can be verified by results of bacterial culture growth from either a fresh pustule or a sample of contaminated water.
Adequate chlorination of the hot tub is necessary to prevent recurrences and to protect others from infection. Symptomatic relief may be achieved through the use of acetic acid 5% compresses for 20 minutes, 2 to 4 times a day.