Permethrin
Permethrin 5% cream is the first-line treatment for Scabies. It is a synthetic pyrethroid insecticide that kills both mites and eggs (DermNet). It treats scabies, not eczema. It matters for toddler eczema because scabies is a common mimic, and a toddler wrongly treated with Topical Corticosteroids can develop “scabies incognito”, where the mites keep spreading under the steroid (DermNet 2025).
Permethrin [treats] Scabies Scabies [relates] Differential Diagnosis of Toddler Eczema
Use in toddlers. It is licensed in the UK for children aged 2 months and over, and the FDA also approves it from 2 months (emc SmPC; CDC). Experience between 2 and 23 months is limited, so under-2s are treated only under medical supervision. Children aged 1–5 use up to 7.5 g (a quarter of a 30 g tube) per application. In under-2s it goes on the whole body, including the face, ears and scalp, avoiding the eyes and mouth; gloves can stop the child licking it off. It is left on for 8–12 hours (CDC: 8–14), reapplied to the hands if they are washed, and repeated after 7 days (DermNet: 7–10). All household and close contacts are treated at the same time, even without symptoms. Bedding, towels and recently worn clothes are washed, and outer garments aired for 72 hours (DermNet).
Permethrin [relates] Parent Experiences
Interaction with eczema care. The SmPC advises withholding steroid treatment of eczema-like reactions before permethrin, because steroids reduce the immune response to the mite and can make the infestation worse. The SmPC also says not to apply it to broken skin, which is awkward in a toddler whose eczema is scratched open; this is for the prescriber to weigh. Burning, stinging or tingling soon after application is common and usually mild. Redness, swelling, “eczema” and itch afterwards are generally part of scabies itself. Itch can persist for up to 4 weeks after successful treatment as a reaction to dead mites, and is not by itself a sign of failure (emc SmPC).
Permethrin [contradicts] Topical Corticosteroids Permethrin [relates] Itch-Scratch Cycle
Safety and alternatives. Even a full 30 g tube on a 2-month-old (about 350 mg/kg) would be unlikely to cause systemic toxicity, according to the SmPC. Allergy to pyrethroids rules it out, and allergy to chrysanthemums or other Compositae needs caution. The cream contains benzyl alcohol, which can cause allergic reactions. If permethrin fails or is unavailable, alternatives include benzyl benzoate, malathion or oral ivermectin; French dermatology guidance (2024) considers ivermectin an option from 2 months if topicals fail, under specialist advice (DermNet). The CDC notes ivermectin is not FDA-approved for scabies.
Compositae Allergy [relates] Permethrin
Connections
- Scabies — first-line treatment from 2 months, source: emc SmPC; CDC
- Differential Diagnosis of Toddler Eczema — treatment for the scabies mimic, source: DermNet 2025
- Topical Corticosteroids — withhold before permethrin; steroids can mask scabies, source: emc SmPC
- Compositae Allergy — caution if allergic to chrysanthemums, source: emc SmPC