Cutaneous Infectious Diseases Flashcards

A 6-year-old presents with honey-colored crusted lesions around the nose and mouth. What is the most likely diagnosis?

Answer: Non-bullous impetigo

Honey-colored crusts around the mouth and nose in a child are classic for non-bullous impetigo, usually caused by Staphylococcus aureus or Streptococcus pyogenes.

Which organism is the most common cause of bullous impetigo?

Answer: Staphylococcus aureus

Bullous impetigo is caused by exfoliative toxin-producing Staphylococcus aureus, which cleaves desmoglein 1.

A diabetic patient develops a rapidly spreading, exquisitely painful erythema with crepitus and dishwater-gray drainage. What is the priority intervention?

Answer: Urgent surgical debridement

Pain out of proportion, crepitus, and gray drainage suggest necrotizing fasciitis, a surgical emergency requiring immediate debridement.

Erythrasma of the intertriginous areas fluoresces what color under Wood's lamp?

Answer: Coral-red

Corynebacterium minutissimum produces coproporphyrin III, causing coral-red fluorescence under Wood's lamp.

A febrile patient has a sharply demarcated, raised, warm, erythematous plaque on the face. This presentation is most consistent with:

Answer: Erysipelas

Erysipelas involves the superficial dermis and lymphatics, producing a sharply demarcated, raised plaque, most often from Streptococcus pyogenes.

Which finding is characteristic of staphylococcal scalded skin syndrome (SSSS)?

Answer: Positive Nikolsky sign with sparing of mucous membranes

SSSS shows a positive Nikolsky sign and characteristically spares the mucous membranes, distinguishing it from toxic epidermal necrolysis.

First-line treatment for a small, uncomplicated cutaneous abscess is:

Answer: Incision and drainage

Incision and drainage is the primary treatment for a simple cutaneous abscess, with antibiotics reserved for surrounding cellulitis or systemic signs.