||In impetigo contagiosa the causative organisms are usually Group A streptococci or Staphylococcus aureus. The early skin lesions consist of vesicopustules that rupture and dry to heavy yellowish crusts. Both pustules and crusts contain viable bacteria and are contagious. Macerated moist skin is particularly vulnerable to bacterial infection. Surprisingly, impetigo is usually painless and the commonest symptom is a variable pruritus.
By contrast, ulcerative impetigo is a deeper bacterial skin infection, caused most commonly by either Group A streptococci, staphylococci, or a mixture of these bacteria. These lesions are usually both pruritic and tender and may be covered with a yellowish-gray crust.
Bacteria-laden discharge from the middle ear may cause a localized superficial infective dermatitis of the surrounding skin. In this patient, S aureus has caused impetigo of the skin below the conchal bowl. The heavy yellowish crusts are characteristic.