Background
Pseudomonas folliculitis is a community-acquired skin infection, which results from the bacterial colonization of hair follicles after exposure to contained, contaminated water (eg, whirlpools, [1, 2, 3, 4, 5, 6] swimming pools, [7] water slides, bathtubs). Pseudomonas is one of the top three pathogens associated with recreational water use. [8] First reported in 1975 in association with whirlpool contamination, Pseudomonas folliculitis is caused by strains of Pseudomonas aeruginosa that are acquired secondary to skin contamination.
The rash of Pseudomonas folliculitis has also been described following the use of diving suits in both seawater and fresh water immersion, [9, 10] and, less commonly, following the use of contaminated bathing objects (eg, synthetic and natural sponges) or inflatable swim toys. [11, 12, 13, 14] Pseudomonas folliculitis has occurred after skin depilation and with no obvious recreational exposure.
Pseudomonas folliculitis also rarely occurs as a perioral acneiform eruption in patients on long-term antibiotic (eg, tetracycline) therapy for acne. [15]
Pathophysiology
The ubiquitous gram-negative bacterial organism, P aeruginosa, found in soil and fresh water, gains entry through hair follicles or via breaks in the skin. Bacterial serotype O:11 is the most commonly reported isolate for water-associated Pseudomonas folliculitis, but other serotypes that have been reported include O:1, O:3, O:4, O:6, O:7, O:9, O:10, and O:16. Serotype O:11 is possibly more invasive or better adapted to survive in halogenated water.
Minor trauma from wax depilation or vigorous rubbing with sponges may facilitate the entry of organisms into the skin, and a dose-response relationship exists in relation to the degree of water contamination. [11, 12, 16, 17] Hot water, high pH (>7.8), and low chlorine level (< 0.5 mg/L) all predispose to infection.
Etiology
The following three primary environmental conditions are known to be associated with outbreaks of Pseudomonas folliculitis [18, 19, 20] :
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Prolonged water exposure
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Excessive numbers of bathers
Risk factors for Pseudomonas folliculitis include the following [23] :
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Crowding
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Youth
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Wearing of snug bathing suits
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Frequency and duration of exposure
Pseudomonas folliculitis outbreaks have been associated with waterslides and similar water attractions. [24] Superchlorinated water has been advised to decrease the incidence of outbreaks. Inflatable pool toys have also been implicated as a source of infection. [25]
Epidemiology
Frequency
The actual incidence of Pseudomonas folliculitis is difficult to assess because of the transient nature of the bather population. [26]
Race
No racial differences in incidence are known for Pseudomonas folliculitis.
Sex
No sexual differences in incidence are known for Pseudomonas folliculitis.
Age
It may occur at all ages, and even congenital disease has been described. [27]
Prognosis
Most cases of Pseudomonas folliculitis resolve without any adverse reactions.
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Erythematous papulopustules of pseudomonas folliculitis. Courtesy of Mark Welch, MD.
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Erythematous papulopustules of pseudomonas folliculitis, with significant perilesional flare. Courtesy of Andy Montemarano, MD.
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Pseudomonas folliculitis. Courtesy of Hon Pak, MD.
