Pubic lice, commonly known as “crabs,” are tiny parasitic insects that primarily live in coarse human body hair. They can cause discomfort, leading many to wonder about their survival away from a human host, especially in bedding.
Understanding Pubic Lice
Pubic lice, scientifically named Pthirus pubis, are minuscule, six-legged parasites that typically inhabit the hair around the genital area. They are commonly called “crabs” due to their appearance, featuring large front legs resembling crab claws, which help them grasp hair shafts. These insects are yellowish-gray or tan and measure about 1.1 to 2.0 millimeters in length.
Unlike head or body lice, pubic lice prefer the thicker, coarser hair found in the pubic region. They can also infest other body areas with similar hair, such as the armpits, chest, thighs, beard, mustache, eyebrows, and eyelashes. Pubic lice feed exclusively on human blood and are distinct from other louse species, making it unlikely to find them on the scalp.
How Long Pubic Lice Survive Off the Body
Pubic lice rely on human blood for their survival and cannot live long away from a host. If they fall off a person, these parasites generally die within 24 to 48 hours without a blood meal. This short survival period is due to their inability to sustain themselves without consistent feeding and the warm, humid environment provided by the human body.
The eggs of pubic lice, known as nits, require the warmth of body heat to hatch. Nits will not hatch off the body, as they need specific temperature conditions for development. Without a human host, both adult lice and their eggs quickly succumb to dehydration and starvation. This limited off-host survival means transmission through inanimate objects like bedding is possible but less common than direct person-to-person contact.
Clearing Lice from Bedding and Clothing
Given the short survival time of pubic lice off the body, extensive decontamination measures are often not necessary. To eliminate any lice or nits that might have transferred to personal items, wash all bedding, towels, and clothing used by the infested person within two to three days prior to treatment.
These items should be machine-washed in hot water, at least 130°F (54°C), and then dried on the highest heat setting for at least 20 to 30 minutes. High temperatures are effective at killing both lice and their eggs. For items that cannot be washed or dry-cleaned, sealing them in an airtight plastic bag for at least 72 hours will cause any remaining lice to die.
Treating a Pubic Lice Infestation
Treating a pubic lice infestation involves specific medicated products designed to kill the parasites. Over-the-counter options include lotions containing 1% permethrin or mousses and shampoos with pyrethrins and piperonyl butoxide. These products are safe and effective when used according to package instructions.
Apply the chosen treatment to all affected hairy areas of the body, excluding the scalp and eyes, and leave it on for the recommended duration before rinsing. A second treatment after 7 to 10 days is advised to kill any newly hatched lice that may have survived the first application. All sexual partners from the past month should also be informed and treated to prevent re-infestation. If over-the-counter treatments are ineffective or if lice are present in the eyelashes, consult a healthcare professional for diagnosis and stronger prescription options, such as malathion or ivermectin.