Phthiriasis (pediculosis ciliaris)
The CMGs are guidelines on the diagnosis and management of a range of common and rare, but important, eye conditions that present with varying frequency in primary and first contact care.
The CMGs are guidelines on the diagnosis and management of a range of common and rare, but important, eye conditions that present with varying frequency in primary and first contact care.
Infestation of lid margins by the crab louse (Phthirus pubis), a blood-feeding obligate ectoparasite affecting only humans
Most common in sexually active people between 15 and 45 years old
Can be contracted within families through poor hygiene
Intense itching of lid margins
Red watery eye
Unilateral or bilateral
Blepharitis (anterior)
Allergic reactions affecting lid skin
Practitioners should recognise their limitations and where necessary seek further advice or refer the patient elsewhere
Sensitive counselling (i.e. by GP) required as this is a sexually transmitted disease
Remove lice, nits and shells (casts) at slit lamp
Advise on any symptoms of pubic infestation
Sexual partners or family members at risk should have their eyes examined and treated if necessary
Bed linen, towels and clothes should be washed at 60°C for at least 5 min
(GRADE*: Level of evidence=low, Strength of recommendation=strong)
Application of Simple Eye Ointment to the lid margins will suffocate lice (unmedicated ointment, applied twice daily for at least 2 weeks)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)
Permethrin 1% lotion applied to lashes for 10 minutes with eyes closed
NB: insecticides can be toxic to the cornea
(GRADE*: Level of evidence=low, Strength of recommendation=weak)
Referral via GP for management of non-ocular aspects, including tracing and screening close contacts; also screening for other sexually-transmitted diseases
B1 (modified): possible prescription of drugs: telephone GP to discuss referral to STD clinic and for advice on local safeguarding arrangements in the case of a child
Normally no referral.
*GRADE: Grading of Recommendations Assessment, Development and Evaluation (www.gradeworkinggroup.org)
Sources of evidence
Clinical Effectiveness Group (British Association of Sexual Health and HIV) United Kingdom National Guideline on the Management of Phthirus pubis infestation (2007) (http://www.bashh.org/documents/28/28.pdf)
Ma D-L, Vano-Galvan S. Infestation of the eyelashes with Phthirus pubis. CMAJ. 2010;182(4):E187.
Panos GD, Petropoulos IK, Dardabounis D, Gatzioufas Z. Phthiriasis palpebrarum. BMJ Case Rep. 2013; bcr-2013-009272
Ryan MF. Phthiriasis palpebrarum infection: a concern for child abuse. J Emerg Med. 2014;46(6):e159-62
Wu N, Zhang H, Sun FY. Phthiriasis palpebrarum: A case of eyelash infestation with Pthirus pubis. Exp Ther Med. 2017;13(5):2000-2002
This condition is caused by infestation of the eyelashes by the crab louse, which is usually acquired by sexual contact.
Phthiriasis causes the eyelids to become itchy and the eyes to become red and watery. It may be possible to see the eggs of the lice (called nits) clinging to the bases of the eyelashes.
The treatment involves removing the lice and nits at the slit lamp (the clinical microscope used by optometrists and ophthalmologists). Pubic infection can be treated with drugs available without prescription from pharmacies. Patients are advised that they have a sexually transmitted condition and that their partner(s) may need to be examined also. Bed linen, towels and clothes should be washed at 60°C for at least five minutes.
Phthiriasis
Version 9
Date of search 26.03.19
Date of revision 04.07.19
Date of publication 21.02.20
Date for review 25.03.21
© College of Optometrists
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