This disease refers to localized purulent infections of the skin by streptococci. Secondary pyoderma may result from antecedent skin wounds or burns; however, the term pyoderma is usually used to describe streptococcal impetigo or impetigo contagiosa.
This disease is frequent in tropical or subtropical climates but also occurs in northern climates during summer months. The disease is prevalent among children of economically disadvantaged families, and the age group most affected are children 2 to 5 years old.
The majority of infections are by group A streptococci; however, streptococci of serogroups C and G are occasionally the cause. The streptococcal agents associated with streptococcal pharyngitis are different strains than the agents that cause pyoderma. Rheumatic fever is not a complication of streptococcal pyoderma; however, infections with nephritogenic strains of group A streptococci are associated with poststreptococcal glomerulonephritis (PSGN). No evidence indicates that therapy for pyoderma will prevent PSGN.
Clinically, lesions begin as papules that progress into vesicular lesions on an erythematous base. Over the next 4 to 6 days, pustules form, enlarge and then break down, yielding the characteristic crusted skin. The lesions slowly heal and may leave residual depigmented areas. Ecthyma refers to a deeply ulcerated form of impetigo. The lesions are usually located on the extremities. Systemic symptoms are usually absent, but regional lymphadenitis may occur.
Oral antibiotics are the treatment of choice. Cloxacillin, cephalexin, cefadroxil, and cefaclor are all effective choices. Mupirocin ointment applied topically on a TID schedule has achieved cure rates comparable to oral antibiotics. Cost is the factor limiting the routine use of Mupirocin. Good personal hygiene is the most efficient prophylactic measure.