🧴 Ivermectin and Scabies: 2025 Treatment Update

By FRCPathPrep.com | July 2025

For FRCPath Part 2 Medical Microbiology exam prep and clinical relevance

🔍 Why This Matters

Scabies remains a common and sometimes underestimated parasitic skin infection. While permethrin cream has long been the mainstay of treatment, oral ivermectin has gained increasing prominence — especially for crusted scabies, outbreaks, and immunocompromised patients.

This post outlines the 2025 updates from UKHSA, CDC, and WHO on scabies treatment, especially regarding ivermectin — essential knowledge for FRCPath candidates and practicing clinicians.

🦠 Scabies Overview (Quick Recap)

Feature	Details
Pathogen	Sarcoptes scabiei var. hominis
Transmission	Prolonged skin-to-skin contact, fomite contact in crusted scabies
Incubation	2–6 weeks (primary infection) or 1–4 days (re-infection)
Classic Sites	Web spaces of fingers, wrists, axillae, genital area
Crusted Scabies	Seen in immunocompromised; high mite burden; highly infectious

💊 Ivermectin in 2025: What’s New?

Guideline Body	Key 2025 Update
UKHSA	Recommends oral ivermectin (200 µg/kg) in combination with topical therapy for crusted scabies and outbreaks. Now approved under PGD for outbreak control.
CDC (USA)	Reaffirms oral ivermectin as first-line in crusted scabies and recommends it for household contacts in institutional outbreaks.
WHO	Emphasises ivermectin as a mass drug administration (MDA) tool in endemic zones; highlights role in neglected tropical disease (NTD) control.

📌 Ivermectin Use: Summary Table (2025 Update)

Scenario	Ivermectin Role	Dosing
Classic Scabies (uncomplicated)	Second-line if topical fails	200 µg/kg, repeated in 7–14 days
Crusted Scabies	First-line, with permethrin	Days 1, 2, 8, 9, 15 (± Day 22 & 29 if severe)
Outbreaks (care homes, hospitals)	Used for mass treatment with contact tracing	Single or 2-dose schedule depending on severity
Immunocompromised Hosts	Essential as systemic therapy	Extended or repeated regimens

🧴 Combined Regimens (UKHSA 2025 Recommendation)

Drug	Frequency	Notes
Permethrin 5% cream	Days 1, 7 (may repeat)	Apply neck down (include scalp in crusted cases)
Ivermectin (oral)	Days 1, 2, 8, 9, 15	Add Day 22 & 29 if crusted or uncontrolled
Keratolytics (if crusted)	Daily	Remove thick crusts to enhance drug penetration

⚠️ Special Considerations

Patient Group	Notes
Children <15 kg	Ivermectin is not licensed, but used off-label in some settings
Pregnancy	Caution advised; permethrin preferred
Liver disease	Use ivermectin with caution; monitor LFTs
Contact Management	Treat all close contacts simultaneously (even if asymptomatic)

🏥 Infection Control & Public Health (UKHSA 2025)

• Crusted scabies = High priority for infection control

• PPE mandatory during care

• Isolation until effective treatment (usually 3–5 days post ivermectin start)

• Notify Public Health in institutional outbreaks

📚 Exam Pearls for FRCPath Part 2

• Know when to escalate to ivermectin, especially in institutional or immunosuppressed settings.

• Understand the combination regimens and public health protocols in outbreak control.

• Be aware of off-label use, safety profiles, and consent implications in special groups.

🔗 References & Guideline Sources

• UKHSA (2025). Scabies: Management in Community and Institutional Settings

• CDC (2024). Scabies Treatment Guidelines

• WHO (2024). Neglected Tropical Diseases: Scabies Fact Sheet

• NICE CKS (2025 Update): Scabies Management

🧠 Final Thought

Ivermectin is no longer just an alternative — it’s a cornerstone in scabies control where topicals fall short. For FRCPath candidates and clinicians, knowing when, how, and with what to combine ivermectin is critical.