Ivermectin

💊 Ivermectin and permethrin are antiparasitic treatments used in dermatology. For scabies, treatment may involve permethrin 5% cream and/or oral ivermectin. For papulopustular rosacea, a different preparation — ivermectin 10 mg/g cream, also known as Soolantra® — may be used in adults.

🎯 Key Distinction

🕷️ Scabies: Overview

Scabies is caused by the mite Sarcoptes scabiei, which burrows into the skin and triggers an itchy hypersensitivity reaction. The itch is often worse at night and commonly affects finger webs, wrists, axillae, waistline, buttocks and genital skin. In older adults, infants, immunosuppressed patients and people in care settings, the presentation may be more widespread or atypical.

🧴 Permethrin 5% Cream for Scabies

🧴 Permethrin 5% cream is usually the first-line topical treatment for classical scabies in UK practice. NICE CKS advises permethrin 5% cream or oral ivermectin, with repeat treatment after 7 days.

• Apply to the whole body, including finger webs, under nails, soles, genital area and buttocks.
• In adults, it is often applied from the neck down, but scalp and face may need treatment in infants, older adults, immunosuppressed patients, or crusted scabies.
• Leave on for the recommended time, commonly 8–12 hours, then wash off.
• Repeat after 7 days because eggs may survive the first treatment.
• Reapply to hands if they are washed during the treatment period.
• Treat all household, sexual and close contacts at the same time.

💊 Oral Ivermectin for Scabies

💊 Oral ivermectin is a useful alternative or adjunct in selected scabies cases. NICE CKS lists a dose of 200 micrograms/kg, followed by a second dose after 7 days. UKHSA emphasises that ivermectin should be used for confirmed scabies, not for itching alone.

• Often considered when topical treatment is difficult, impractical, poorly tolerated or has failed.
• May be helpful in institutional outbreaks, under specialist/public health guidance.
• Important in crusted scabies, where mite burden is very high and infectivity is much greater.
• Does not reliably kill eggs, so repeat dosing is needed.
• Dosing is weight-based, so accurate body weight is important.

🧬 How Ivermectin Works

• Ivermectin binds to parasite glutamate-gated chloride channels.
• This increases chloride influx, causing parasite paralysis and death.
• Humans do not have these parasite-specific channels, which gives selective toxicity.
• In rosacea, topical ivermectin may also reduce inflammation and may reduce Demodex mite burden.

🌹 Ivermectin Cream for Rosacea

🌹 Ivermectin 10 mg/g cream, also known as Soolantra®, is licensed for the topical treatment of inflammatory lesions of papulopustular rosacea in adults. NICE reviewed this indication and describes it specifically for papulopustular rosacea, not simple facial flushing alone.

• Used for rosacea with papules and pustules.
• Usually applied once daily to affected areas of the face, depending on product guidance.
• Avoid the eyes, lips and mucous membranes.
• It is not the same as oral ivermectin tablets used for scabies.
• It is not a steroid cream.
• Response may take several weeks; reassess if ineffective or poorly tolerated.

🔴 Rosacea: Clinical Features

• Central facial redness affecting cheeks, nose, chin or forehead.
• Papules and pustules in papulopustular disease.
• Flushing triggered by heat, alcohol, spicy food, sunlight or stress.
• Burning, stinging or sensitive skin.
• Ocular symptoms may occur, including gritty eyes or blepharitis.

⚠️ Important Safety Points

• Do not confuse ivermectin tablets with ivermectin cream; they are used differently.
• Do not use ivermectin for unproven indications such as viral infections.
• Check pregnancy, breastfeeding, age and weight considerations before oral ivermectin.
• For scabies, persistent itch after treatment does not automatically mean treatment failure.
• For rosacea, worsening irritation, eye symptoms or diagnostic uncertainty should prompt review.

🧼 Scabies: Preventing Reinfection

• Treat close contacts at the same time, even if asymptomatic.
• Wash clothing, bedding and towels according to local advice.
• Avoid close skin contact until treatment has been completed as advised.
• Consider outbreak control measures in care homes, wards, prisons or other closed settings.
• Seek public health or dermatology advice for crusted scabies or outbreaks.

🧠 Exam Pearls

• Permethrin 5% cream is usually first-line for classical scabies.
• Oral ivermectin is useful when topical therapy is difficult, has failed, or for crusted scabies/outbreaks.
• Both permethrin and ivermectin scabies regimens usually require a repeat treatment after 7 days.
• Ivermectin 10 mg/g cream is for papulopustular rosacea in adults.
• Post-scabetic itch can persist for weeks due to ongoing immune reaction, not necessarily live mites.

🩺 Clinical Reasoning

In scabies, symptoms are driven by a delayed hypersensitivity response to mites, eggs and faeces, so itch can continue after the mites have been killed. This is why clinicians should distinguish ongoing infestation from post-scabetic itch, especially if no new burrows or contacts are affected. In papulopustular rosacea, ivermectin cream is used because Demodex mites and cutaneous inflammation may contribute to inflammatory lesions. The same drug name therefore appears in two different contexts: oral ivermectin for parasites such as scabies, and topical ivermectin cream for inflammatory rosacea lesions.

📚 UK Guidance Notes

• NICE CKS supports permethrin 5% cream or oral ivermectin for scabies management, with repeat treatment after 7 days.
• UKHSA advises that oral ivermectin for scabies should be used when scabies is confirmed, not for itching alone.
• NICE evidence summary describes ivermectin 10 mg/g cream as licensed for inflammatory lesions of papulopustular rosacea in adults.
• Always check local formulary, BNF and product guidance before prescribing.