Impetigo

Impetigo is a skin infection caused by streptococci or staphylococci and appears as crusting or bullae. It is most common in 2-5 years olds. Children should stay out of school until healing of crusted lesions. When caused by group A streptococci, impetigo may be complicated by glomerulonephritis.

CASES/YEAR
4,500,000 (US); 90,000,000 (Global)
AGENT TYPE
Bacteria
OTHER NAMES
Pyoderma;
ACUITY
Acute-Moderate
INCUBATION
Estimated: days to weeks;
INITIAL SYMPTOMS
"Impetigo is a superficial skin infection with crusting or bullae caused by streptococci, staphylococci, or both. Ecthyma is an ulcerative form of impetigo." [Merck Manual, p. 998]
PRECAUTIONS
Contact until 24 hours after initiation of effective therapy;
COMMENTS
Most common in children 2-5 years old; Regional lymphadenopathy is common. Systemic symptoms are not common. Bullous impetigo is almost always S. aureus. Children should stay out of school until healing of crusted lesions. Topical therapy is usually effective for mild and localized impetigo; [ABX Guide] Complications include lymphadenitis, poststreptococcal glomerulonephritis, bacteremia, osteomyelitis, septic arthritis, and pneumonia. [5MCC-2020] Children with AIDS frequently suffer from recurrent cellulitis, impetigo, and folliculitis usually caused by S. aureus. [ID, p. 1019] When caused by group A streptococci, impetigo may be complicated by glomerulonephritis. [Cohen, p. 88] Beginning within 10 days after the onset of skin lesions, glomerulonephritis complicates about 2 to 5% of cases of nonbullous impetigo in children. [Cecil, 24th Ed, p. 2529]
DIAGNOSTIC
Clinical; Gram stain: gram positive cocci;
SCOPE
Global
SIGNS & SYMPTOMS
  • H lymphadenopathy
  • S entry wound with lymph nodes
  • S lymphadenitis, acute
  • S lymphangitis
  • S papules or plaques
  • S pustule
  • S skin blister or vesicles
  • S ulcer of skin
  • *arthritis
  • *glomerulonephritis
  • *osteomyelitis
  • *pneumonia
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Skin or Mucous Membranes (Includes Conjunctiva)
SOURCE
Person-to-Person
RESERVOIR
Human
RISK FACTORS
  • AIDS patients
REFERENCES FOR CASES/YEAR
1. (US) 10-20 cases per 1000; Calculate: 15 x 300,000 = 4.5 million (US);
2. (Global) 20 X US cases/yr;