Body lice are parasitic insects that live on clothing and bedding, migrating to the human body only to feed on blood. These insects can transmit diseases, such as louse-borne relapsing fever and epidemic typhus, though this is rare in many parts of the world. Eliminating an infestation requires thorough action, treating both the body and eradicating the insects from the environment.
Recognizing Body Lice Infestation
Body lice are small, tan to grayish-white insects, about the size of a sesame seed. They primarily reside in the seams of clothing and bedding, where they lay their small, oval-shaped eggs, called nits. Lice move onto the skin several times a day to feed, causing intense itching that results from an allergic reaction to their saliva.
Common symptoms include a rash and tiny, red bite marks, often concentrated around the waist, groin, armpits, and shoulders, where clothing seams touch the skin. Unlike other types of lice, body lice do not live or lay most of their eggs on the body hair. Infestation is diagnosed by finding live lice or nits cemented to the fibers within the seams of clothing.
Treating the Infested Body
The initial step in treating an infested individual is improving personal hygiene. This often resolves the problem if environmental control is strict. Treatment involves bathing daily with soap and warm water, followed immediately by changing into clean, freshly laundered clothes. Since lice only visit the body to feed, removing the clothing disrupts their life cycle.
If the infestation remains after consistent hygiene measures, a topical pediculicide treatment may be necessary. Over-the-counter (OTC) options often contain 1% permethrin or pyrethrins, which are applied to the entire body, avoiding the face. These chemical treatments are insecticides and must be used exactly according to the product label instructions to ensure effectiveness and safety.
For severe infestations or cases where OTC treatments are not successful, a healthcare provider may prescribe stronger medications. Prescription options include topical treatments like malathion lotion or oral medications such as ivermectin. Some medications are not ovicidal and require a second application after 7 to 10 days to kill newly hatched lice.
Cleaning Clothing and Belongings
Environmental eradication is a fundamental step because the lice and their eggs live almost entirely on fabric items. All clothing, bedding, and towels used by the infested person must be laundered using high heat. Items should be washed in hot water, at a temperature of at least 130°F (54.5°C), which is lethal to the parasites.
Following the wash cycle, all items must be dried using the dryer’s high-heat setting for a minimum of 20 minutes to ensure complete kill of any surviving lice or eggs. For non-washable items, such as certain outerwear or plush toys, alternative methods are available. Dry cleaning is an effective option because the chemicals and heat involved are toxic to the insects.
Another alternative for non-washable articles is to seal them in an airtight plastic bag. While adult body lice die from starvation within 1 to 2 days without a blood meal, the eggs can survive longer. Sealing the items for a full two weeks ensures that any eggs have hatched and the resulting nymphs have died before the items are used again.
Preventing Recurrence
Following the initial treatment, vigilance is necessary to prevent recurrence. Monitoring involves checking the seams of clothing and bedding for signs of live lice or new nits, especially in the week following treatment. If live lice are discovered 7 to 10 days after a non-ovicidal treatment, a second treatment of the body is recommended to kill any newly hatched lice that survived the first application.
Long-term prevention centers on maintaining consistent personal hygiene and regular laundering of clothing. Avoiding the sharing of clothing, bedding, or towels is an important preventive measure, as this is the most common way body lice spread. Since these parasites thrive in conditions of overcrowding and infrequent changes of clothing, ensuring a clean environment minimizes the risk of future infestation.