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A 42-year-old woman is seen for multiple papules and pustules on her back (Figure 123-1). Further questioning demonstrates that she was in a friend's hot tub twice over the previous weekend. The outbreak on her back started after she went into the hot tub the second time. This is a case of Pseudomonas folliculitis or "hot tub" folliculitis. The patient avoided this hot tub and the folliculitis disappeared spontaneously. Another option is to treat with an oral fluoroquinolone that covers Pseudomonas.

FIGURE 123-1

"Hot-tub" folliculitis from Pseudomonas aeruginosa in a hot tub. (Reproduced with permission from Richard P. Usatine, MD.)


Folliculitis is an inflammation of hair follicles, usually from an infectious etiology. Multiple species of bacteria have been implicated, as well as fungal organisms.


  • Folliculitis is a cutaneous disorder that affects all age groups and races, and both genders.

  • It can be infectious or noninfectious. It is most commonly of bacterial origin (Figures 123-2 and 123-3).

  • Pseudofolliculitis barbae is most frequently seen in men of color and is made worse by shaving (Figure 123-4).1

  • Acne keloidalis nuchae is commonly seen in black men or men of color but can also be seen in women (Figures 123-5 and 123-6).2

  • Eosinophilic folliculitis is described in patients with HIV infection (Figure 123-7).

  • Methicillin-resistant Staphylococcus aureus (MRSA) can pose a challenge to the treatment of folliculitis (Figure 123-8).

FIGURE 123-2

Close-up of bacterial folliculitis showing hairs coming through pustules. (Reproduced with permission from Richard P. Usatine, MD.)

FIGURE 123-3

Chronic bacterial folliculitis (biopsy proven) on the shoulders and back with scarring and hyperpigmentation. (Reproduced with permission from Richard P. Usatine, MD.)

FIGURE 123-4

Pseudofolliculitis barbae in a black man. Shaving makes it worse and he notes many problems with ingrown hairs. (Reproduced with permission from Richard P. Usatine, MD.)

FIGURE 123-5

Acne keloidalis nuchae with inflamed papules and pustules on the neck of a young Hispanic man. (Reproduced with permission from Richard P. Usatine, MD.)

FIGURE 123-6

Acne keloidalis nuchae in a woman, demonstrating the folliculitis around the hair follicles and the scarring alopecia that has occurred. (Reproduced with permission from Richard P. Usatine, MD.)

FIGURE 123-7

Eosinophilic folliculitis on the back of an HIV-positive man. (Reproduced with ...

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