-IBIS-1.5.0-
tx
cutaneous system
impetigo
diagnoses

definition and etiology

definition: superficial vesiculopustular skin infection mainly seen in children; also called "impetigo contagiosa" and "ecthyma" (when the impetigo is ulcerative)

etiology: The associated microorganism is primarily Group A beta-hemolytic streptococcus, although staph aureus is being implicated in a growing number of cases (in the past staph was limited to only bullous impetigo). Impetigo is primarily seen in children under 5 years old, and appears on exposed areas like the lower legs, arms or face. The infection may follow trauma to the skin, scabies, insect bites, fungal infections, fleas, various kinds of dermatitis, or may just appear on normal skin.

signs and symptoms

signs and symptoms:
• lesions: rapid progression of lesions from maculopapules to vesicopapules or bullae, and a thick, honey-colored, sticky exudate that crusts
• itching: scratching can easily spread the infection
• ecthyma: localized, shallow, punched-out ulcerations that are covered with a brown-black crust and surrounded by erythematous tissue; may progress rapidly and leave a scar
• with either type, there may be fever, malaise and lymphadenopathy

lab findings:
• (+) blood findings of infection
• may have increased WBC count
• (+) culture of staph and/or strep from skin lesion
• ASO titer may be useful

course and prognosis

Untreated infection may develop into cellulitis, lymphangitis, or furunculosis and there may be pigment changes and/or scarring of the affected tissues. Acute glomerulonephritis may develop in children after skin infection with strep.

differential diagnosis

• herpes zoster
• varicella
• contact dermatitis


footnotes