Pseudomonas aeruginosa folliculitis: causes, symptoms, diagnosis, treatment, and prevention

Pseudomonas aeruginosa folliculitis, also known as hot tub folliculitis, occurs after baths in the warm bathroom, hot tub, or public swimming pool, contaminated with pseudomonas aeruginosa, and is characterized by pruritic follicular papules, vesicles, and pustules.


Pseudomonas aeruginosa is an aerobic Gram-negative bacillus, is widely present in moist natural environments, mainly in the soil, water, and intestines of few persons, and can also temporarily parasitize the anus, genitals, armpits, and external auditory canal. Under normal circumstances, its growth is inhibited by Gram-positive cocci, generally nonpathogenic. However, the bacterium can quickly reproduce in the burns, ulcers, and moist skin, causing skin infections. Systemic infections usually occur in persons with low immunity, such as patients whose normal microflora being inhibited by antibiotics or glucocorticoids, tumor patients, patients with granulocytopenia caused by various causes, patients with immunodeficiency caused by chronic wasting diseases, frail old adults, and malnourished infants. If a healthy person is immersed in water for a long time, the infection of the bacteria can also occur. The bacteria can also cause nosocomial infections by contamination of hospital bedpans and sheets, and has become one of the main pathogens of nosocomial infections in recent years.

Studies have shown that the pathogenicity of the bacteria is mainly caused by the secreted exotoxin, and the collagenase, elastase, and phospholipase secreted by the bacteria are involved in the disease. A typical strain produces two pigments of blueish green pyocyanin and yellowish green pyoverdin.

Systemic pseudomonas aeruginosa infection can cause sepsis, and patients present with fever, jaundice, splenomegaly, pneumonia, urinary tract infection, and meningitis. Cutaneous pseudomonas aeruginosa infection often occurs in the persistently moist lesion sites, especially on the periumbilical and burned surfaces of infants, as well as in macerated toes, external auditory canal, and auricle.

Signs and Symptoms

Skin eruption occurs 1 - 4 days, usually 2 days, after baths in the hot tub, and is characterized by several to several hundred, pinhead sized, follicular papules or vesicles on the erythema, rapidly developing into pustules, with subjective pruritus, mostly in the lateral trunk, armpits, buttocks and the proximal extremities, as well as breasts, probably accompanied by systemic symptoms such as various degrees of fever, fatigue, earache, nausea, and vomiting. Generally, skin lesions spontaneously heal within 7 - 14 days, and systemic infections are rare.


According to the systemic pustular rash, a history of baths in the hot tub, and epidemiology, the disease can be considered. The definitive diagnosis can be based on the results of bacteriological examination and culture in the specimens with pus and hot tub water. Serotype II of the bacterium is usually isolated.


The rashes usually spontaneously resolve, treatment is unnecessary, and oral ceftazidime or ciprofloxacin can be administered in patients with systemic symptoms or long duration.


Preventive measures should be strengthened. The water in the swimming pool should be regularly filtered and disinfected with hypochlorites. The free chlorine level should be kept at 1ppm, the pH should be between 7.2 and 7.8, and the water should be changed frequently to keep the water clean.