Head lice are tiny parasitic insects, roughly the size of a sesame seed, that live exclusively on the human scalp and feed on blood. They are common, especially among school-age children, but the risk of acquiring them from a brief interaction like a hug is extremely low.
How Head Lice Move Between People
Head lice cannot jump, fly, or hop between people. Their movement is restricted to crawling, facilitated by six legs equipped with specialized claws that tightly grip a single hair shaft.
The primary method of transmission is direct head-to-head contact. This requires the hair strands of an infested person to physically overlap with the hair strands of a non-infested person long enough for the louse to crawl across the bridge of hair. Prolonged contact is common during activities like sleepovers or playing games, not typically during a brief, upright hug.
The Truth About Casual Contact Risk
Casual contact presents a negligible risk because lice are adapted to live only in the warm, blood-rich environment of the human scalp. Once separated from a host, an adult louse will quickly dehydrate and become inactive. It will die within 24 to 48 hours without a blood meal, as it needs to feed multiple times a day to survive.
This short survival window explains why transmission through indirect contact, or fomites, is uncommon. Items like hats, scarves, pillows, or furniture do not pose a significant risk because any louse that falls off will soon be too weak or dead to establish a new infestation. Concerns about brief contact with upholstered surfaces are largely unfounded and do not warrant extensive house cleaning.
What to Do After Potential Exposure
If you suspect close contact with someone who has lice, the first step is a thorough head check. Focus on screening rather than immediate chemical treatment, which is unnecessary unless a live infestation is confirmed.
The most reliable method is wet combing, which involves saturating the hair with conditioner and meticulously combing through it with a fine-toothed detection comb. Systematically comb the entire head, paying particular attention to the hair near the nape of the neck and behind the ears, where lice and their eggs, called nits, are most frequently found. If you find live lice or firmly attached nits, an over-the-counter treatment can be used according to package directions. Regular checking for a few weeks ensures any newly hatched lice are caught early.