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Year : 2023  |  Volume : 3  |  Issue : 1  |  Page : 148-150

A rare case of bilateral Phthiriasis palpebrarum with crab louse

1 Cornea and Anterior Segment, LV Prasad Eye Institute, GMR Varalakshmi Campus, Visakhapatnam, Andhra Pradesh, India
2 Ocular Microbiology Service, LV Prasad Eye Institute, GMR Varalakshmi Campus, Visakhapatnam, Andhra Pradesh, India

Date of Submission25-Jul-2022
Date of Acceptance31-Aug-2022
Date of Web Publication20-Jan-2023

Correspondence Address:
Rohit Dureja
Cornea and Anterior Segment Services, L V Prasad Eye Institute, GMR Varalakshmi Campus, Hanumanthawaka Jn, Visakhapatnam - 530 040, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1819_22

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Phthiriasis palpebrarum is a rare cause of blepharitis in which Pthirus pubis infests the eyelashes. We report a case of bilateral Phthiriasis palpebrarum with crab louse. A 48-year-old woman presented with severe itching in both eyes for 4 days. Careful slit-lamp examination revealed multiple motile lice and nits in the eyelashes of both eyes with mild conjunctival hyperemia. Treatment was started by manually removing all the adult lice and eyelashes where nits were seen adhering and by the application of petrolatum jelly. After 2 weeks, she was symptomatically better with no louse or nit on her eyelashes on ocular examination.

Keywords: Blepharoconjunctivitis, Phthiriasis palpebrarum, Pthirus pubis

How to cite this article:
Dureja R, Madduri B. A rare case of bilateral Phthiriasis palpebrarum with crab louse. Indian J Ophthalmol Case Rep 2023;3:148-50

How to cite this URL:
Dureja R, Madduri B. A rare case of bilateral Phthiriasis palpebrarum with crab louse. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Feb 1];3:148-50. Available from: https://www.ijoreports.in/text.asp?2023/3/1/148/368176

Phthiriasis palpebrarum, caused by Pthirus pubis, is an uncommon cause of blepharoconjunctivitis. Three types of lice, the body louse (Pediculus humanus corporis), the head louse (Pediculus humanus capitis), and the pubic louse (crab louse), infest humans. All three feed on blood and reproduce on the body when sanitary practices are inadequate, leading to pediculosis (by Pediculus corporis and Pediculus capitis) and Phthiriasis (by Phthirus pubis). Typically, Phthiriasis pubis, or crab louse, is found in the hair of the pubic and inguinal regions. Risk factors for Phthiriasis palpebrarum are poor hygiene and overcrowding. It is most prevalent in sexually active patients, generally between 15 and 45 years old. In adults, transmission of P. pubis to eyelashes may occur either manually by the infested body hair or during sexual contact. Indirect transmission through clothes or towels contaminated with nits is less frequent. The average lifespan of P. pubis is about 4 weeks, passing through three stages: nits, nymphs, and adults. Nits are operculated, oval-shaped, white, or dark and remain attached to the base of hair near the skin where they find an ideal temperature to incubate. They are hard to remove. After 5–10 days, a nymph comes out and develops into an adult in 7–10 days. Without a host, it cannot survive for more than 1 day. The adult louse has a short stout body with three pairs of legs and well developed claws in the second and third pairs of legs, which is typical of the crab louse. The most anterior pair of legs is slender, with fine claws and a serrated surface. Posterior pairs are thick for an improved grasp of hair shafts and attachment of eggs. Clinically, Phthiriasis palpebrarum presents as itching, erythema, discoloration of skin as dark-brown or red spots, excoriation of eyelid skin, conjunctivitis, and rarely keratitis with adult lice and nits appearing as white flakes. These symptoms can be over-looked by clinicians and easily mis-diagnosed as anterior blepharitis. When it occurs, genital involvement must be suspected.[1],[2],[3],[4] We report a rare case of bilateral Phthiriasis palpebrarum.

  Case Report Top

A 48-year-old female presented to us with severe itching in both eyes for 4 days. Slit-lamp examination revealed inflamed, crusty lid margins with yellowish deposits near the eyelash bases [Figure 1]a and [Figure 1]b and multiple motile adult lice adhering to the eyelashes with translucent oval nits attached to the cilia in the eyelids of both eyes. She gave a systemic history of diabetes mellitus and had undergone multiple vitreo-retinal procedures for proliferative diabetic retinopathy and cataract extraction with posterior chamber intra-ocular lens implantation in the right eye. The best corrected visual acuity in the right eye was counting fingers close to the face and 20/40 in the left eye.
Figure 1: Slit-lamp image (diffuse illumination) of yellow-brown deposits in the upper eyelids of the right eye (a) and left eye (b)

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A clinical diagnosis of bilateral Phthiriasis palpebrarum was made on the basis of multiple motile adult lice adhering to the eyelashes, noted on slit-lamp examination and confirmed by examination of epilated lashes smeared on slides under a light microscope. Examination of the wet mount under a light microscope (10× objective lens) revealed live adult forms [Figure 2]a of P. pubis and their nits [Figure 2]b with a typical morphology. Improvement of personal hygiene was stressed upon, and treatment of close contacts was advised. She was treated by manually removing all the adult lice and epilation of eyelashes where nits were seen adhering under a slit-lamp microscope with the application of petrolatum jelly (Vaseline) twice daily. After 2 weeks, she was symptomatically better and no louse or nit was noted on her eyelashes.
Figure 2: (a) Adult Pthirus pubis as seen through a microscope; (b) brown translucent egg of Pthirus pubis attached to the eyelashes as seen through a microscope

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  Discussion Top

Phthiriasis palpebrarum can easily be confused with seborrheic, infective, or allergic blepharitis. The mode of infestation and its presentation by P. pubis around the roots, burrowing under the skin, itching, irritation, erythematous lesions of eyelid skin, follicular conjunctivitis, and marginal keratitis, are similar to anterior blepharitis, hence resulting in mis-diagnosis. However, slit-lamp bio-microscopy under high magnification can help in identifying adult lice and nits adhering to the eyelashes, avoiding a mis-diagnosis.[2]

Management of Phthiriasis palpebrarum is challenging. The most effective and popular treatment of eyelid lice is direct removal of the lice and nits with fine forceps under a slit-lamp microscope. Application of white petrolatum twice daily for 7 to 10 days is also effective in killing adult lice.[3] Petrolatum jelly (Vaseline) is made from a waxy petroleum material that covers the lice and closes their breathing holes, thereby preventing respiration and movement.[3] Other treatment modalities include mercuric oxide 1%,[4] but it may cause chemical blepharitis. Pilocarpine 4% gel (anticholinesterase eye ointments)[5] and oral ivermectin[6] have also been tried. Application of 1% gamma-benzene hexachloride cream[7] and pyrethrin ointment[8] are other options. In our case, we mechanically removed all the adult lice and nits buried in the eyelids with forceps under a slit-lamp microscope. The application of petrolatum jelly (Vaseline) twice daily was advised. Patients should be screened for other sexually transmitted infections. All sexual contacts and family members should be evaluated for the presence of palpebral or pubic infestation.

  Conclusion Top

Phthiriasis palpebrarum can be over-looked by clinicians and easily mis-diagnosed as anterior blepharitis. It is suggested that eyelids and eyelashes should be carefully examined by slit-lamp microscopy under high magnification to avoid mis-diagnosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Nuttall GH. The biology of Phthirus pubis. Parasitology 1918;10:383-405.  Back to cited text no. 1
Thappa DM, Karthikeyan K, Jeevankumar B. Phthiriasis palpebrarum. Postgrad Med J 2003;79:102.  Back to cited text no. 2
Burns DA. The treatment of Pthirus pubis infestation of the eyelashes. Br J Dermatol 1987;117:741-3.  Back to cited text no. 3
Ashkenazi I, Desatnik HR, Abraham FA. Yellow mercuric oxide: A treatment of choice for phthiriasis palpebrarum. Br J Ophthalmol 1991;75:356-8.  Back to cited text no. 4
Kumar N, Dong D, Jenkins D. Pubic lice effectively treated with Pilogel. Eye 2003;17:538-9.  Back to cited text no. 5
Burkhart CN, Burkhart CG. Oral ivermectin therapy for phthiriasis palpebrarum. Arch Ophthalmol 2000;118:134-5.  Back to cited text no. 6
Solomon LM, Fahrner L, West DP. Gamma benzene hexachloride toxicity. A review. Arch Dermatol 1977;113:353-7.  Back to cited text no. 7
Klaus S, Shvil Y, Mumcuoglu KY. Generalized infestation of a 3-1/2-year-old girl with the pubic louse. Pediatr Dermatol 1994;11:26-8.  Back to cited text no. 8


  [Figure 1], [Figure 2]


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