How do bites from head lice look? - briefly
Bite marks from head lice appear as tiny, «red papules», often clustered near the hairline, behind the ears, or at the nape of the neck. The lesions may be surrounded by a thin halo of irritation and typically develop within 24‑48 hours after infestation.
How do bites from head lice look? - in detail
The marks left by head lice are typically tiny, erythematous papules measuring about 1–2 mm in diameter. They appear as isolated spots or small clusters, most often on the scalp, nape of the neck, behind the ears, and occasionally on the shoulders. The lesions are usually red, slightly raised, and may exhibit a central punctum where the insect’s mouthparts penetrated the skin.
Within a few hours after a feeding event, the papule can become a faint wheal surrounded by a pale halo. Itching is common and may intensify after 12–24 hours. Repeated scratching can produce excoriations, crusting, or secondary bacterial infection, altering the original appearance.
Key visual characteristics:
- Size: 1–2 mm, sometimes up to 3 mm in swollen reactions.
- Color: bright red to pink, occasionally darkening to a bruise‑like hue if inflammation persists.
- Shape: round or slightly oval, with a smooth, well‑defined margin.
- Distribution: linear or grouped pattern following hair shafts; rarely isolated on non‑hairy skin.
- Evolution: initial papule → wheal with halo → possible crusted excoriation if scratched.
Differential considerations include mosquito bites, which are typically larger, more irregular, and often located on exposed limbs, and allergic dermatitis, which presents with diffuse erythema rather than discrete punctate lesions. The presence of live lice or nits on the hair shaft confirms the diagnosis.