Definitions of the levels of evidence (I-IV) and grades of recommendation (A-C) are repeated at the end of the "Major Recommendations" field.
Diagnosis
- This is based on finding adult lice and/or eggs.
- Examination under light microscopy can confirm the morphology if necessary.
Management
General Advice
- Patients should be advised to avoid close body contact until they and their partner(s) have completed treatment and follow-up.
- Patients should be given a detailed explanation of their condition, and clear and accurate written information on applying the treatment.
Further Investigation
A full screen for other sexually transmitted infections should be undertaken, although few data are available to determine the likelihood of additional diagnoses in a United Kingdom population.
Treatment
A number of treatments are available. The recommendation of some agents is based on successful results when treating head lice; there is no evidence to give an efficacy rate for pubic lice.
Head lice develop resistance to pediculicides, and local rotation of treatments to combat this may restrict availability of treatments for pubic lice. However, since 1996, there have not been any studies in the English language that have documented significant treatment failure in the management of pubic lice.
Lotions are likely to be more effective than shampoos, and should be applied to all body hair including the beard and moustache if necessary.
A second application after 3 to 7 days is advised.
Recommended Regimens
- Malathion 0.5%. Apply to dry hair and wash out after at least 2, and preferably, 12 hours, (i.e., overnight) (Level of evidence IV, Grade of recommendation C).
- Permethrin 1% cream rinse. Apply to damp hair and wash out after 10 minutes (Level of Evidence II, Grade of recommendation B).
- Phenothrin 0.2%. Apply to dry hair and wash out after 2 hours (Level of evidence IV, Grade of recommendation C).
- Carbaryl 0.5 and 1% (unlicensed indication). Apply to dry hair and wash out 12 hours later (Level of evidence IV, Grade of recommendation C).
Infestation of eyelashes can be treated with permethrin 1% lotion, keeping the eyes closed during the 10-minute application (Level of evidence IV, Grade of recommendation C).
Alternatively, an inert ophthalmic ointment with a white or yellow paraffin base such as simple eye ointment BP may be applied to the eyelashes twice daily for 8 to 10 days (Level of evidence IV, Grade of recommendation C). This works by suffocating lice and avoids any risk of eye irritation by topical insecticide.
Allergy
Treatments to which there is known hypersensitivity should be avoided.
Pregnancy and Breastfeeding
Permethrin is safe during pregnancy and breastfeeding.
Sexual Partners
- Current sexual partners should also be examined and treated.
- Contact tracing of partners from the previous 3 months should be undertaken.
Follow-Up
- Patients should be re-examined for the absence of lice after 1 week.
- Treatment failures should be given an alternative from the above list.
- It should be explained to patients that dead nits may remain adherent to hairs. This does not imply treatment failure, and the nits can be removed with a comb specifically designed for that purpose.
Definitions:
Levels of Evidence
Ia: Evidence obtained from meta-analysis of randomised controlled trials
Ib: Evidence obtained from at least one randomised controlled trial
IIa: Evidence obtained from at least one well designed controlled study without randomisation
IIb: Evidence obtained from at least one other type of well designed quasi-experimental study
III: Evidence obtained from well designed non-experimental descriptive studies such as comparative studies, correlation studies, and case control studies
IV: Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities
Grading of Recommendations
A (Evidence levels Ia, Ib)
- Requires at least one randomised controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation.
B (Evidence levels IIa, IIb, III)
- Requires availability of well conducted clinical studies but no randomised clinical trials on the topic of recommendation.
C (Evidence level IV)
- Requires evidence from expert committee reports or opinions and/or clinical experience of respected authorities. Indicates absence of directly applicable studies of good quality.
