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Important: change to recommendations for treating pubic lice in pregnancy and breast feeding.

We have been notified by the National Teratology Information Service (NTIS) that the recommendations for treating pubic lice in pregnancy have changed since the Clinical Knowledge Summaries topic review on pubic lice, which we referenced in the Bulletin, was published. NTIS now recommend the use of either topical permethrin or malathion for the treatment of pubic lice in pregnancy. [Personal communication. NTIS.] Either malathion or permethrin topical preparations may also be used to treat pubic lice in breastfeeding mothers of full-term, healthy infants [Personal communication. UK Drugs in Lactation Advisory Service.]

Summary

These Bulletins provide an overview of the diagnosis and management of head lice, classic scabies, threadworm and pubic lice in primary care. In the absence of specific national guidance, treatment and management recommendations are largely taken from Clinical Knowledge Summaries guidance. Many of the recommendations are based on expert opinion and a pragmatic approach, informed by what is known of the respective parasites’ lifecycles, rather than robust evidence.

Head louse infestation is a common problem, especially among young children. They are associated with few clinical consequences, but some people experience stigma and anxiety. Structured detection combing is more reliable than simple direct visual inspection for confirming active infestation. Treatment should be used only if a live louse has been detected. Treatment options are wet combing for a minimum of four sessions spaced over two weeks, insecticides (e.g. aqueous malathion 0.5% lotion or phenothrin 0.5% liquid) or dimeticone 4% lotion, which require two applications seven days apart. Patients should be advised that these recommendations may differ from the instructions included in the packaging of some insecticide products. The choice of approach largely depends on patient preference and history of treatments used, as there is little consistent, robust evidence of superiority of one approach over another. Evidence for the effectiveness of other treatments, such as tea tree oil, is limited to anecdote, and the common perception that ‘natural’ products are ‘safer’ may be false. Education of patients and carers is essential and must include detection, treatment techniques and assessment of success.

Scabies is highly contagious, increasingly prevalent, and often mistaken for other pruritic skin conditions. Diagnosis is mainly by clinical examination and history; parasitological confirmation is not required before treating. All close contacts and household members should be treated simultaneously, even if they have no symptoms. Recommendations are to use permethrin 5% dermal cream first-line unless contraindicated, as this is best supported by evidence. For other aspects of treatment the evidence is generally very limited. Patients need detailed instructions on how to use treatments and need to comply with these to prevent reinfestation. Contact tracing over the previous two months is recommended.

Threadworm infestation is most common in pre-school children but the risk of transmission to family members is high. Treatment should be offered to the individual if threadworms have been seen or their eggs have been detected, but all members of the household should be treated simultaneously, even if they have no symptoms. Hygiene measures are essential, whether anthelmintic treatment is used or not. Mebendazole is generally the preferred agent, but piperazine (combined with senna) is also an option. There is very little evidence for anthelmintic treatments but it is generally accepted that cure rates with either agent are 90–100%. Adoption of strict hygiene measures for at least 6 weeks is the only alternative for those who cannot have or do not want anthelmintic treatment (e.g. pregnant women).

Pubic louse infestation needs to be confirmed by the detection of live lice/viable eggs. It is most common in young adults, as it is often acquired during sexual contact. It is important to establish whether pubic lice have been acquired in this way or not, as there may be a need to refer the individual to a genitourinary medicine clinic for screening for sexually transmitted infections. Contact tracing over the previous 3 months is recommended. There is very little evidence for treatments of pubic lice and recommendations are based on expert opinion in the main. Aqueous malathion 0.5% liquid or permethrin 5% dermal cream are recommended for application to the entire body and should be repeated after 7 days. Patients should be advised that these recommendations may differ from the instructions included in the product packaging.

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