What is the difference between head lice and pubic lice? - briefly
Head lice (Pediculus humanus capitis) live on scalp hair, spread by direct head‑to‑head contact, are larger, and lay nits close to the skin. Pubic lice (Pthirus pubis) inhabit coarse body hair, especially in the genital region, are smaller with a crab‑like shape, and their eggs are deposited farther from the skin.
What is the difference between head lice and pubic lice? - in detail
Head and pubic lice belong to different species within the order Phthiraptera. The former, Pediculus humanus capitis, inhabits scalp hair, while the latter, Pthirus pubis, prefers the coarse hair of the genital region, though it may also be found on eyebrows, chest, or armpits.
Biology and appearance
- Size: head lice average 2–3 mm; pubic lice are slightly larger, about 1.5–2 mm in width but bulkier due to a crab‑like shape.
- Body shape: head lice have a slender, elongated form; pubic lice possess a broader, flattened body with a wider abdomen.
- Legs: both have six legs, but the hind legs of pubic lice are adapted for grasping thicker hair shafts.
Habitat preferences
- Head lice cling to scalp hair, laying eggs (nits) close to the scalp where temperature is optimal for development.
- Pubic lice attach to the hair of the pubic area, where the environment is cooler and hair is coarser; they also survive on other body hair with similar texture.
Transmission routes
- Direct head‑to‑head contact spreads scalp lice; sharing combs, hats, or pillows can also transmit them.
- Pubic lice are primarily transmitted through sexual contact; they may also be passed via contaminated bedding, towels, or clothing, though such routes are less common.
Clinical manifestations
- Head lice cause itching, irritation, and the presence of visible nits attached to hair shafts. Heavy infestations can lead to secondary bacterial infection from scratching.
- Pubic lice produce intense itching in the genital area, often accompanied by small bluish macules (bite marks) and a grayish‑white crust at the base of hairs.
Life cycle
- Both species undergo three stages: egg, nymph, adult.
- Egg incubation: head lice eggs hatch in 7–10 days; pubic lice eggs hatch in 6–10 days.
- Nymphal development: three molts over 9–12 days for head lice; 9–12 days for pubic lice.
- Adult lifespan: head lice survive up to 30 days on the host; pubic lice live about 30 days, requiring a blood meal every 2–3 days.
Treatment options
- Pediculicides such as permethrin 1 % lotion or pyrethrins with piperonyl‑butoxide are first‑line for scalp infestations; thorough combing removes nits.
- For pubic lice, 1 % permethrin cream, 5 % malathion lotion, or ivermectin (oral) are recommended; washing clothing and bedding at 60 °C eliminates residual insects.
- Resistance to common pediculicides has been reported in both species, prompting the use of alternative agents or combination therapy.
Prevention
- Avoid sharing personal items that contact hair; maintain regular hair hygiene.
- Practice safe sexual behaviors, use barrier methods, and inspect partner’s pubic region after new sexual encounters.
- Launder potentially contaminated fabrics promptly at high temperature.
These distinctions clarify identification, transmission dynamics, symptomatology, and appropriate management for each type of lice.