What are the symptoms and treatment options for Pediculosis (lice infestation)?

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From the Guidelines

Symptoms and Treatment of Pediculosis (Lice Infestation)

Lice infestations are typically treated with topical medications, including permethrin 1% cream rinse applied to the hair for 10 minutes, then rinsed, or pyrethrin 0.33% shampoo applied to the hair for 10 minutes, then rinsed 1.

  • The symptoms of pediculosis include intense itching, especially at night, and the presence of lice or nits (eggs) in the hair.
  • Treatment options also include malathion 0.5% lotion, which has high ovicidal activity, but should be reapplied if live lice are seen in 7 to 10 days 1.
  • For cases resistant to these treatments, oral ivermectin 200-400 mcg/kg may be administered as a single dose, repeated in 7-10 days if necessary 1.
  • Treatment should also include washing and drying clothing, bedding, and towels in hot water and high heat to kill lice and nits.
  • It is essential to note that no healthy child should be excluded from or allowed to miss school time because of head lice, and no-nit policies for return to school should be abandoned 1.
  • Additionally, manual removal of nits immediately after treatment with a pediculicide is not necessary to prevent spread, but may be considered in the school setting to decrease diagnostic confusion 1.

From the FDA Drug Label

For the treatment of Head Lice, Pubic (Crab) Lice and Body Lice Inspect examine each household member with a magnifying glass in bright light for lice/eggs (nits) look for tiny eggs (nits) near scalp, beginning at the back of neck and behind ears if either lice or eggs (nits) are found, treat with this product 1 HEAD LICE head lice lay small white eggs (nits) on the hair shaft close to the scalp eggs (nits) are most easily found on the back of the neck or behind the ears 2 PUBIC (CRAB) LICE pubic (crab) lice may be contracted by sexual contact sexual partners should be treated simultaneously to avoid reinfestation lice are very small and look like brown or grey dots on the skin pubic (crab) lice usually cause intense itching and lay small white eggs (nits) on the hair shaft 3 BODY LICE body lice and their eggs (nits) are generally found in the seams of clothing, particularly in the waistline and armpit areas

The symptoms of Pediculosis (lice infestation) include:

  • Intense itching
  • Presence of tiny eggs (nits) near the scalp, particularly at the back of the neck and behind the ears
  • Presence of lice, which are very small and look like brown or grey dots on the skin The treatment options for Pediculosis (lice infestation) include:
  • Applying a lice-killing shampoo, such as pyrethrin, to dry hair or other affected area
  • Using a special lice/nit or fine-toothed comb to remove lice and their eggs (nits)
  • Disinfecting clothing, bedding, and other items by machine washing in hot water and using the hottest dryer setting
  • Treating sexual partners simultaneously to avoid reinfestation in the case of pubic (crab) lice 2

From the Research

Symptoms of Pediculosis

  • Pruritus is the most common presenting symptom of pediculosis, as well as scabies 3, 4
  • Head and pubic lice infestations are diagnosed with visualization of live lice 3
  • Nits (lice eggs or egg casings) alone are not sufficient to diagnose a current infestation 3
  • Body lice infestation should be suspected in patients with pruritus who live in crowded conditions or have poor hygiene 3

Treatment Options for Pediculosis

  • First-line pharmacologic treatment for pediculosis is permethrin 1% lotion or shampoo 3
  • A single ten-minute application of 1% permethrin cream rinse was well tolerated, highly effective, and therapeutically superior to a single four-minute application of 1% lindane shampoo 5
  • Combination therapy with 1% permethrin and trimethoprim/sulfamethoxazole is an effective alternative therapy for head lice infestation 6
  • Oral ivermectin is an option for the treatment of head lice infestation, especially in individuals who have experienced a treatment failure 7
  • Noninsecticidal agents, including dimethicone and isopropyl myristate, show promise in the treatment of pediculosis 3
  • Extensive environmental decontamination is not necessary after pediculosis is diagnosed, but clothing and bedding of persons with scabies or body lice should be washed in hot water and dried in a hot dryer 3, 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Lice and Scabies: Treatment Update.

American family physician, 2019

Research

1% permethrin cream rinse vs 1% lindane shampoo in treating pediculosis capitis.

American journal of diseases of children (1960), 1986

Research

Oral ivermectin for the treatment of head lice infestation.

American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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