Bacterial and Viral Infections, NEET PG & INI-CET Dermatology MCQs

Explanation

Impetigo is a superficial bacterial skin infection, caused by Staphylococcus aureus or Streptococcus pyogenes, with characteristic honey-coloured crusts, common in children. It is treated with topical or oral antibiotics.

Explanation

Erysipelas is a superficial dermal streptococcal infection with a sharply demarcated, raised, red border, unlike cellulitis, which is deeper with less distinct margins. It commonly affects the face or legs and is treated with penicillin-class antibiotics.

Explanation

Herpes zoster (shingles) is reactivation of latent varicella-zoster virus, producing a painful vesicular rash confined to one dermatome and not crossing the midline. Early antivirals reduce severity and the risk of post-herpetic neuralgia.

Explanation

Molluscum contagiosum, a poxvirus infection, produces pearly, dome-shaped papules with central umbilication, common in children and spread by contact. It is usually self-limiting in the immunocompetent.

Explanation

Cutaneous warts are caused by human papillomavirus infecting keratinocytes. They are common, often self-limiting, and treated when needed with salicylic acid, cryotherapy, or other destructive methods.

Explanation

Staphylococcal scalded skin syndrome, caused by exfoliative toxins of Staphylococcus aureus, causes superficial peeling with a positive Nikolsky sign, mainly in young children. The split is high in the epidermis, so it usually heals without scarring.

Explanation

Cellulitis, a deep dermal and subcutaneous infection with warmth, erythema, swelling, and tenderness, is usually caused by Streptococcus pyogenes and Staphylococcus aureus. Treatment is with appropriate systemic antibiotics.