Scabies and pediculosis (lice infestation) are common parasitic skin conditions. They spread easily through close contact and cause severe itching and irritation. Anti-scabies and anti-pedicular agents are medicines used to kill the mites or lice responsible for these infections.
Scabies – Overview
Scabies is caused by the mite Sarcoptes scabiei. The female mite burrows into the skin, lays eggs, and causes intense itching, especially at night.
Symptoms of Scabies
- Severe itching, worse at night
- Rashes and small bumps
- Burrow lines on skin
- Common sites: between fingers, wrists, elbows, waist, and armpits
Pediculosis – Overview
Pediculosis is infestation caused by lice. Types include:
- Head lice – Pediculus humanus capitis
- Body lice – Pediculus humanus corporis
- Pubic lice – Pthirus pubis
Symptoms of Pediculosis
- Itching and irritation of scalp or skin
- Visible lice or nits (eggs)
- Red bumps and scratches
Classification of Anti-Scabies and Anti-Pedicular Agents
These drugs are mainly topical agents applied to skin or hair.
- Permethrin
- Benzyl benzoate
- Sulphur ointment
- Lindane (γ-benzene hexachloride)
- Malathion
- Ivermectin (oral or topical)
Drug Profiles
1) Permethrin
Permethrin is one of the safest and most effective agents for both scabies and head lice.
Mechanism: Disrupts the nerve membrane of mites and lice, causing paralysis and death.
Uses: Scabies (5% cream), lice (1% lotion).
2) Benzyl Benzoate
A traditional scabicide widely used in many countries.
Mechanism: Penetrates the mite and kills it by neurotoxicity.
Note: Can cause skin irritation; not preferred in children.
3) Sulphur Ointment
An older but safe topical agent.
Mechanism: Toxic to mites and lice; also has antibacterial properties.
Uses: Safe for infants and pregnant women.
4) Lindane (Gamma Benzene Hexachloride)
Effective but associated with toxicity.
Mechanism: Interferes with the parasite’s nervous system.
Caution: Neurotoxicity risk; avoid in infants and pregnant women.
5) Malathion
An organophosphate used mainly for resistant head lice.
Mechanism: Inhibits cholinesterase in lice, causing paralysis.
6) Ivermectin
Works for both scabies and lice, especially in severe or resistant cases.
Mechanism: Stimulates inhibitory nerve receptors causing paralysis of mites and lice.
Forms: Oral tablets or 1% topical lotion.
How These Agents Work
Most anti-scabies and anti-lice agents act by:
- Paralyzing mites or lice
- Disrupting their nerve function
- Inhibiting vital enzymes
- Killing both adult parasites and sometimes eggs
General Treatment Guidelines
- Apply topical agents to all affected areas of the body.
- Repeat treatment after 7–10 days if needed.
- Wash clothes, bedding, and towels in hot water.
- Treat close contacts to prevent reinfection.
- Ivermectin is used when topical therapy fails or is not feasible.
Side Effects
- Mild burning or stinging sensation
- Redness or rash
- Dryness or irritation
- Rarely, allergic reactions
Detailed Notes:
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