Early Scabies Rash: Itchy Red Bumps in Finger Webs, Wrists, Elbows, Waist, Buttocks, and Genitals

Scabies (Sarcoptes scabiei var. hominis) presents with intense pruritus (worse at night) and a characteristic distribution:

Classic Sites (Symmetrical)

• Interdigital webs (fingers).
• Flexor wrists.
• Anterior axillary folds.
• Periumbilical, belt line.
• Buttocks, genitalia (penile shaft, scrotum, labia).
• Areolae (women).

Morphology

• Burrows: Thin, grayish, serpiginous 2–10 mm lines (pathognomonic but often obscured).
• Papules: 1–3 mm erythematous, excoriated.
• Vesicles/pustules: Secondary bacterial infection (impetiginization).
• Nodules: Persistent granulomatous reaction (genital, axillae).

Atypical Presentations

• Crusted (Norwegian) scabies: Hyperkeratotic plaques, minimal itch, high mite burden — immunocompromised, elderly, institutionalized.
• Infants: Face, scalp, palms, soles involved.

Diagnosis

Skin scraping + KOH/light microscopy (mite, eggs, scybala). Dermoscopy: "delta wing" sign. Empiric treatment if high suspicion.

Treatment

Permethrin 5% cream (full body, 8–14 hrs, repeat 1 wk) or oral ivermectin 200 µg/kg (repeat 1 wk). Treat all close contacts simultaneously. Environmental decontamination (hot wash/dry, seal items 72 hrs).