The skin accounts for approximately 15% of the total body weight, and its main function is to protect and act as a barrier to dangerous pathogens. However, given that it is the largest organ of the body and is constantly undergoing exposure, it is susceptible to injury. Lacerations and abrasions create portals of entry for pathogens and often compromise the integumentary system.
Many patients present to their primary-care providers with concerns related to the integumentary system. A common chief complaint is the “spider bite.” Frequently, these patients present with a single painful, tender, erythematous, swollen nodule on the skin. The location of the lesion varies from patient to patient, but is often found in places that are more prone to abrasions and in areas that are cosmetically shaved. Sometimes the lesions are draining purulent discharge. They are always painful, and this concern is often the catalyst for the patient to present in clinic.
Methicillin-resistant Staphylococcus aureus (MRSA) was first identified in the 1960s, and in 2005 was thought to have been the cause of about 90,000 cases of invasive infection in the United States. MRSA is a common cause of both community- and hospital-acquired soft-tissue abscesses and skin infections. Skin abscesses are often treated empirically with oral antibiotics and incision and drainage, and can be managed in the outpatient setting. Culture and sensitivities should be obtained from any draining abscess. Due to a high incidence of MRSA, beta-lactam antibiotics are no longer reliable agents for empiric treatment. Clindamyacin, trimethoprim-sulfamethoxazole (Bactrim), or tetracyclines are the first line treatment. Treatment should be prescribed for one to two weeks, and follow-up should be done in 24-48 hours. Incision and drainage (I&D) may be indicated for lesions that are fluctuant but not draining. Following this procedure, lesions that are >5 cm in diameter or near the coccyx should be packed. In addition, packing should be placed after I&D for lesions that occur on diabetic or immune-compromised patients.
Patients are often concerned and confused regarding the etiology of skin abscesses. Many are convinced that they have been bitten by a spider and are reluctant to accept your explanation for the cause. This often hinders educating the patient on prevention. Typically, after a recurrence of infection, patients begin to become more receptive to understanding that staph is a common dermatologic pathogen and one that does not usually cause problems unless there is a break in the skin and a portal of entry allows for infection to populate. Teaching adequate skin hygiene and the avoidance of activities such as tattoos, IV drug use, cosmetic shaving, and sharing of razors that increase the risk of skin breakdown is important to prevent recurrent infections in those that are susceptible.