BACTERIAL INFECTIONS
Posted by recep on June 25th, 2009BACTERIAL INFECTIONS
Impetigo
A superficial skin infection caused by staphylococci or streptococci. Vesicles or pustules in the early stages break down to form golden brown crusts that often adhere to the underlying skin. If the infection is extensive, malaise, fever, and lymphadenopathy may occur. Impetigo often develops as a secondary infection in conditions characterized by breaks in the skin that allow microbes to penetrate (eg, eczema, senile pruritus, pediculosis, nodular prurigo, and herpes zoster).
Treatment: Single or localized lesions should be soaked for 10 min in a drying agent such as Burow’s solution (aluminum acetate 5%). Extensive lesions require systemic antibiotics to reduce the risk of glomerulonephritis and prevent impetigo from spreading. A skin swab should be taken for microbial culture and sensitivity assays.
Patients with streptococcal pyoderma should be treated with penicillin V 250 to 500 mg orally qid for 10 days. If patient compliance is unlikely, long-acting penicillin G benzathine 1.2 million u. IM may be necessary. If the patient is allergic to penicillin, erythromycin 250 to 500 mg orally qid can be given. Patients with staphylococcal pyoderma should receive dicloxacillin 250 to 500 mg orally qid for 10 days.
Staphylococcal Scalded Skin Syndrome
(Ritter’ s Disease)
A severe, extensive bullous condition caused by a staphylococcal skin infection, in which the epithelium lifts off in sheets leaving large denuded areas. Although generally a disease of young children, the condition is increasingly appearing in immunocompromised adults. In elderly patients, staphylococci usually invade the skin and the blood, and death usually results from septicemia.
Toxic epidermal necrolysis, an adverse drug reaction that can produce an identical clinical picture, must be considered in the differential diagnosis. Both these conditions are life threatening and require hospitalization. To differentiate between staphylococcal scalded skin syndrome and toxic epidermal necrolysis, the examiner observes a frozen section from a skin scraping or biopsy to determine the level of cleavage. In staphylococcal scalded skin syndrome, cleavage occurs within the epidermis just below the granular layer. In toxic epidermal necrolysis, subepidermal blister formation occurs with basal cell damage. Differentiation is important because staphylococcal scalded skin syndrome must be treated immediately with penicillinase-resistant antistaphylococcal antibiotics.
Treatment: Therapy is the same as for severe burns, beginning with immediate fluid and electrolyte replacement. A systemic antibiotic (eg, IV oxacillin) should also be given promptly. The source of infection may be difficult to isolate, but culture specimens should be taken from the skin, blood, nares, and any other suspected sites. Silver sulfadiazine cream may help prevent cutaneous superinfection with gram-negative bacteria. Even with treatment, the prognosis is poor.
