Pseudomonas folliculitis is an uncommon, often misdiagnosed dermatitis in children. The first outbreak of folliculitis caused by Pseudomonas aeruginosa was reported in 1975.1 The source was traced to a contaminated whirlpool in which 42 of 49 adolescents who used the pool that day contracted pruritic skin rashes along with varying degrees of fever, malaise, vomiting, conjunctivitis and/or pharyngitis. Since then numerous outbreaks traced to contaminated whirlpools or swimming pools,2, 3 as well as occasional sporadic cases associated with contaminated bath articles4 have been reported. In general the patients are adults or children, given that toddlers and infants are less often exposed to heated public baths or pools. We report the case of an 18-month-old toddler who acquired Pseudomonas folliculitis from contaminated bath articles.
An 18-month-old boy presented with a 6-week history of a pruritic rash consisting of numerous papules and some papulopustules. The rash initially appeared on the abdomen and then spread to the arms and legs. As older papulopustules healed, leaving behind hyperpigmented macules, new erythematous papules developed interspersed among the old lesions. The resultant rash revealed a mixture of macules, papules and papulopustules of different sizes and pigmentation occurring predominantly on the lower extremity. The patient was afebrile and otherwise in good general condition. Treatment with a topical antibiotic cream (fucidic acid) for 1 week followed by an oral antibiotic for another week (amoxicillin/clavulanic acid) was unsuccessful.
Culture of a skin pustule, which grew P. aeruginosa, was initially regarded as a contaminant. Subsequent culture of another pustule also revealed P. aeruginosa. Repeated courses of topical therapy with a desiccating antifungal/antibacterial cream with anti-Pseudomonas activity (clotrimazole/hexamidine) brought only temporary improvement. When the sources of contamination, the child's wash cloth and plastic bath mat, both culture-positive for P. aeruginosa, were identified and removed, the rash resolved promptly.
P. aeruginosa is an ubiquitous inhabitant of moist surfaces, but certain conditions, such as high water pH (>7.8) and low chlorine content, aggravated by high water temperature, which increases chlorine evaporation, favor rapid growth.1–3 P. aeruginosa does not survive on dry surfaces. In sporadic cases of Pseudomonas folliculitis, persistently moist bath sponges,5, 6 toys or plugs4 have been found to harbor P. aeruginosa. The presence of desquamated epithelial cells, as found in exfoliative sponges, further enhances growth of P. aeruginosa. 6 Most but not all cases of Pseudomonas folliculitis are caused by serogroup 0:11. It is not clear whether this is caused by increased virulence of this serogroup or by an enhanced ability to survive in the above-mentioned habitats.3
The rash of Pseudomonas folliculitis begins as an erythematous, pruritic papule, which progresses to a small papulopustule. The papulopustule heals spontaneously in 2 to 5 days, leaving a hyperpigmented macule in its place. New papulopustules occur as older ones resolve, particularly in cases with persistent exposure, so that patients present with lesions in various stages of development. Characteristic of this folliculitis is its predilection for the buttocks, thighs and axillae, perhaps because of the higher moisture and exposure to friction in these areas, which might facilitate acquisition of the organism.2, 3 The skin rash is often accompanied by otitis externa or mastitis, occasionally by conjunctivitis or pharyngitis, and sometimes by systemic signs such as fever, malaise and lymphadenopathy. The illness regresses spontaneously in 7 to 10 days, unless exposure to the source of contamination continues, in which case recurrent folliculitis or chronic abscesses may occur.2, 3
Although the rash of Pseudomonas folliculitis is well-characterized, it is not unique and is therefore often initially mistaken for staphylococcal folliculitis, impetigo, insect bites, scabies, varicella-zoster, herpes simplex or contact dermatitis.2, 3, 7 The diagnosis is established by the history of exposure along with a positive culture from a pustule. The presumed source of contamination should also be sampled for culture to facilitate initiating appropriate hygienic measures.
Treatment of Pseudomonas folliculitis consists primarily of removal of the offending agent or cessation of exposure to the source of contamination.2, 3, 7 Topical therapy with gentamicin8 or a desiccating antimicrobial such as clotrimazole/hexamidine (the hexamidine component has anti-Pseudomonas activity) may accelerate healing. In severe or complicated cases some authors have used systemic therapy with ciprofloxacin.8
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