Folliculitis is infection and inflammation of hair follicles. Hair follicles are present all over the body except palms and soles. So practically Folliculitis can occur anywhere in the body except palms and soles. Hair follicles are portals of large number of bacteria.
Causative organisms of Folliculitis:
The commonest organism of Folliculitis is Staphylococcus aureus and it usually causes localized folliculitis. Other causative organisms are Pseudomonas aeruginosa, Propionibacterium acnes (causative organism of acne or pimples), Schistosoma species etc.
Diffuse folliculitis can occur in two settings, “hot-tub” folliculitis and “swimmer’s itch”. Hot-tub folliculitis occurs when waters is insufficiently chlorinated and maintained at temperatures of 37–40°C and the infection is generally self limiting (although bacteremia and shock may occur rarely). The causative agent in hot-tub folliculitis is Pseudomonas aeruginosa. Swimmer’s itch occurs when a skin surface is exposed to water infested with freshwater avian schistosomes (Schistosoma species). Free-swimming schistosomes can readily penetrate human hair follicles but quickly die and elicit a brisk allergic reaction which cause intense itching and erythema.
Sebaceous glands empty into hair follicles and ducts and if they are blocked they form sebaceous cysts, which may resemble staphylococcal abscesses. Chronic folliculitis is uncommon except in acne vulgaris (a form of folliculitis), which is generally caused by normal flora Propionibacterium acnes.
Treatment of folliculitis:
If the organisms are sensitive to beta-lactum antibiotics, they should be used first. Examples of beta-lactum antibiotics are penicillins (older and newer synthetic penicillin like amoxycillin), cephalosporins (like Cefazolin) etc. If the organisms are not sensitive to beta-lactum antibiotics, vancomycin (1 gm intravenously every 12 hourly) or linezolid (600 mg intravenously every 12 hourly) should be used. Sometimes tetracycline and trimethoprim-sulfamethoxazole can also be used.