Head Lice – Pediculosis Capitis

Head lice infestation is highly contagious and most common in children aged 3–12 in school or day care settings, but affects all groups. The main symptom is intense scalp itch due to a reaction to louse saliva.

Symptoms and Onset:

• Itch: Intense scratching, especially at the nape of the neck and behind the ears. Itch may start 2–6 weeks after the first exposure.

• Caregiver reports: Poor sleep, irritability, and noticing "white dots" on the hair that cannot be brushed off (nits/eggs).

• Transmission: Occurs primarily through head-to-head contact. Lice cannot jump or fly.

Crucial Note for Darker Skin Tones:
Parents may report significant scratching, hair manipulation, or patchy hair thinning resulting from the itch, rather than visible redness of the scalp. The condition is not a sign of poor hygiene and can affect any hair type.

The best method for diagnosis is wet combing with a fine-toothed nit comb and conditioner under good light.

Scalp and Hair Findings:

• • Live Lice: 2–3 mm, grey/white to tan, move quickly away from light. Usually found near the nape of the neck and behind the ears.

  • Nits (Eggs): Oval, 0.5–1 mm, and firmly glued to the hair shaft. Viable nits are brown and found within a few millimeters of the scalp; empty nits are white/translucent and further down the hair.

  • Skin Changes: Excoriated (scratched) papules and crusts on the scalp, nape of the neck, and shoulders.

  • Complications: Look for signs of secondary impetigo (honey-coloured crusts, oozing) and lymphadenopathy (swollen nodes, especially posterior cervical).

Key Examination Nuances in Darker Skin Tones:

• • Erythema (redness) is often subtle or absent. Look instead for:

    • Hyperpigmented or darkened excoriations and Post-inflammatory Hyperpigmentation (PIH) along the nape and hairline.

    • Repeated scratching can lead to lichenification (thickened, dark plaques) and a higher risk of keloids or hypertrophic scars at excoriated sites.

  • Nits are often easily visible as white specks against dark hair, but must be distinguished from dandruff (which flakes off) and hair shaft casts (which slide easily).

Management requires both eradication of lice and nits and decontamination of the environment and close contacts.

1. Topical Pediculicides (First-line):

• Options: Permethrin 1% lotion, Dimethicone 4% (a non-insecticidal suffocating agent with low resistance), Malathion, or Topical Ivermectin 0.5%.

• Application: Apply the product to dry or towel-dried hair, saturating the scalp from root to tip. Do not use conditioner beforehand.

• Repeat Treatment: A second application 7–10 days later is essential for most products to kill newly hatched lice, as they are not fully ovicidal.

2. Mechanical Removal (Wet Combing):

• Apply conditioner to wet hair and use a fine-toothed nit comb, sectioning the hair and combing from scalp to tip.

• Repeat every 3–4 days for at least 2–3 weeks until no lice are found on 3 consecutive sessions. This method can be used alone or combined with topical agents.

3. Environmental Measures:

• Washing: Wash bedding, towels, and clothing used in the past 48 hours in hot water and dry on high heat.

• Non-washable items: Seal items like stuffed toys or headphones in plastic bags for 2 weeks.

• Hygiene: Soak combs/brushes in hot water. Reinforce no sharing of personal items.

Special Considerations for Darker Skin Tones:

Hair Care: Temporary loosening or careful sectioning of braids, locs, or weaves may be needed for thorough combing and product application.

Avoid Trauma: Minimize rough combing or harsh chemical agents to reduce the risk of PIH, scarring, hair breakage, and traction alopecia.

Complications: Treat secondary bacterial infections (impetigo) with topical or oral antibiotics. Treat itch-related eczema with mild topical steroids and emollients.

Skinsight – Head Lice (Pediculosis Capitis): https://skinsight.com/skin-conditions/pediculosis-capitis-head-lice/

NCBI Bookshelf – Pediculosis (StatPearls): https://www.ncbi.nlm.nih.gov/books/NBK470343/

DermNet NZ – Head Lice: https://dermnetnz.org/topics/head-lice