Hot tub folliculitis is an infection of the hair follicles that results from exposure to certain bacteria that live in warm, wet areas.
Most folliculitis is caused by the common organism Staphylococcus aureus. However, hot tub folliculitis is caused by Pseudomonas aeruginosa. Pseudomonas survives in hot tubs, especially hot tubs made of wood, unless the water's acid and chlorine levels are strictly controlled.
Hot tub folliculitis can be seen within several hours to 2 days of exposure. It first appears as itchy bumps, some of which may be filled with pus. It may then develop into dark red tender nodules. The rash may be thicker under swimsuit areas, where the material has held the contaminated water in contact with the skin for a longer period of time.