🦷 Scabies Permethrin Treatment Simulator

The Mite Burrows In and Begins Laying Eggs

A fertilized female mite tunnels into the stratum corneum, short placeholder.

• ~0.4mm: Mite size (barely visible to eye)
• ~2mm/day: Burrow speed (placeholder pace stat)
• 2–3/day: Eggs laid (placeholder over lifetime)
• ~4–6wk: Mite lifespan (on host, placeholder)

Burrow tunnel anatomy

Short placeholder: thin winding track in top skin layer.

Egg and fecal pellet deposition

Short placeholder: eggs and scybala left along the tunnel.

Placeholder highlight: burrow line plus a terminal papule marks active mite.

Larvae Hatch, Mature, and Colonize New Sites

Placeholder lead: eggs hatch into larvae that molt and re-burrow elsewhere.

• ~3–4 days: Hatch time (placeholder incubation)
• 10–15: Typical mite load (placeholder classic scabies)
• webs, wrists: Favored sites (placeholder distribution)
• spared: Face/scalp (adults) (placeholder note)

Larva-to-adult molting

Short placeholder: larva molts through nymph stages to adult.

Typical body distribution

Short placeholder: finger webs, wrists, waistline, elbows favored.

Placeholder highlight: adults usually spare the face and scalp.

Delayed Hypersensitivity to Mite, Egg, and Fecal Proteins

Placeholder lead: itching reflects immune sensitization, not raw mite count.

• 2–6 wk: Onset after exposure (placeholder first infestation)
• 1–2 days: Reinfestation onset (placeholder sensitized host)
• worse at night: Itch pattern (placeholder circadian note)
• allergic reaction: Cause (placeholder not toxin)

Why itching lags infestation

Short placeholder: sensitization takes weeks to develop fully.

Nocturnal itch pattern

Short placeholder: warmth in bed increases mite activity, itch.

Placeholder highlight: itch severity does not track live mite count.

Whole-Body 5% Permethrin Cream, Neck Down

Placeholder lead: full-body coverage is essential, not just visible burrows.

• 5%: Concentration (placeholder permethrin cream)
• 8–14 hr: Contact time (placeholder overnight application)
• neck down: Coverage area (placeholder whole body)
• spot-treating: Common error (placeholder missed sites)

Application protocol

Short placeholder: apply to all skin from neck downward.

The partial-coverage mistake

Short placeholder: treating only visible burrows leaves mites alive.

Placeholder highlight: incomplete coverage is a leading cause of treatment failure.

Mites Die, But Itching Can Persist for Weeks

Placeholder lead: post-scabietic itch is expected and not treatment failure.

• ~24–48 hr: Mite clearance (placeholder full-coverage dose)
• 2–4 wk: Itch persistence (placeholder residual reaction)
• >4–6 wk: Retreat threshold (placeholder new burrows only)
• key step: Patient education (placeholder prevents overtreatment)

Dead mite, live allergy

Short placeholder: residual immune reaction outlives the mites.

When to actually retreat

Short placeholder: new burrows or no improvement after weeks.

Placeholder highlight: itching alone, without new burrows, rarely needs retreatment.