Lice Eggs (Nits): Adhesion, Removal, and Misconceptions

Louse eggs (nits) are firmly cemented to the hair shaft by a glue-like secretion from the female louse's reproductive gland. They are not "sticky" in a loose sense – they do not fall off easily.

Key Facts

• Attachment: Cement covers ~1/3 of nit circumference; resistant to water, normal shampoo, brushing.
• Location: Laid ≤1 cm from scalp (optimal temperature/humidity).
• Removal: Requires mechanical force – fine-toothed nit comb (metal teeth <0.3 mm spacing), fingernails, or chemical loosening agents (enzyme-based, vinegar – limited evidence).
• Viability: Nits >1 cm from scalp are usually hatched/empty or non-viable (wrong temperature).

Why They Sometimes "Fall Off"

• Hair breakage.
• Aggressive combing shears hair shaft.
• Natural hair shedding (telogen).
• Hatching: operculum opens, nymph emerges; empty shell may remain or detach.

Effective treatment requires ovicidal pediculicide + meticulous combing to remove viable nits.