A. Impetigo. Usually caused by group A hemolytic streptococci or coagulase-positive Staphylo-coccus aureus. Appear as redness, thin yellowish crusts, and even bullae, which may be localized or widespread on the skin and develop over days. Itching, pain, and tenderness may occur. Moderately contagious. Treatment is with mupirocin 2% ointment BID or systemic antibiotics, daily bathing with antibacterial soap, and attention to personal hygiene. Need to monitor for the development of poststrepto-coccal glomerulo-nephritis.
B. Ecthyma. Considered a deeper extension of impetigo with the same cause, except it may also be caused by Pseudomonas organisms. It is characterized by a hemorrhagic crust with erythema or induration that develops over weeks. Treatment includes systemic antibiotics as well as débridement of the epidermis, which becomes necrotic. Scars may occur after healing.Cellulitis. Usually caused by group A beta-hemolytic streptococci, it is a suppurative inflammation of the dermis and of subcutaneous tissue. Usually follows trauma or underlying dermatosis, and there is moderate local erythema, tenderness, warmth, and tenseness. Area can become indurated, and frequently streaks of lymphangitis can be seen with involvement of the regional lymph nodes. Systemic symptoms are common, and bacteremia and septicemia may follow. Treatment is with systemic antibiotics and the application of local heat, elevation, and immobilization. For necrotizing fasciitis and synergistic gangrene, early wide surgical excision and débridement is necessary in addition to IV antibiotics.
C. Folliculitis (including sycosis barbae [barber’s itch], pseudofolliculitis, and hot-tub folliculitis). A common problem with predisposing factors such as maceration, friction, and the use of irritant chemicals. Usually caused by S. aureus but occasionally Klebsiella, Pseudomonas (hot-tub folliculitis), Enterobacter or Candida albicans are the causative agents. Appears as a pustule with a central hair (follicle) with or without any surrounding erythema. Scarring may occur with destruction of the hair follicle with severe infections. Tenderness, itching, and pain may occur. Treatment includes avoidance of inciting agents, antiseptic soap washes, and, in severe cases, topical or systemic antibiotics such as dicloxacillin or erythromycin 500 mg QID x 7 to 10 days and mupirocin 2% ointment topically. Complications can include cellulitis, furunculosis, and alopecia.
D. Furuncle (boil). An acute, localized perifollicular abscess of the skin and subcutaneous tissue caused by coagulase-positive S. aureus resulting in a red, hot, very tender inflammatory nodule that exudes pus from one opening. A carbuncle is an aggregate of connected furuncles and characteristically is painful and has several pustular openings. This can be an acute or chronic problem with lesions commonly on areas of friction such as buttocks, axillae, breasts, and the nape of the neck. Treatment involves systemic antibiotics local heat, and rest. Incision and drainage is generally required. Prevention is often difficult. Improved personal hygiene, use of antibacterial soaps, frequent hand washing, daily bathing, and change of clothing are important. Elimination of carrier states in the nose and perineum by the use of topical and systemic antibiotics is often possible.