Parasitic Lid Disease

Question 1

Demodex are mites. What sort of age prevalence do they exhibit in the population?

Answer 1

29% up to age 25, more than that with older age groups

Question 2

What are a few differences between demodex folliculorum and demodex brevis?

Answer 2

Folliculorum is longer, is colonial, lives in the uppersection of the hair follicle, and causes collarettes. Brevis is shorter, solitary, lives in the sebaceous glands, and causes damage and plugging of the glands (potentially leading to dry eye and chalazion).

Question 3

What are a few subjective indications of a demodex infestation?

Answer 3

Itching, burning, crusting, swelling of margins, madarosis

Question 4

What are a few objective indications of a demodex infestation?

Answer 4

Erythema of lid margin, conjunctival injection, blepharitis, collarettes, meibomian gland blockage.

Question 5

How would you treat a demodex infestation?

Answer 5

Aggressive lash scrub in office, tea tree oil products (longer than a week)

Question 6

True or false: medical treatments for demodex are effective within a few days

Answer 6

False; the lifespan of the mites is 3-4 weeks and eggs are laid in 20-egg batches. You need to treat for at least two weeks and possibly longer to make sure the entire infestation is eliminated.

Question 7

What are a few types of lice that can infect the eyelid?

Answer 7

Phthirus public, pediculus corporis, pediculus capitus

Question 8

Lice are a vector of what serious disease?

Answer 8

Typhus

Question 9

Which type of lice is free moving? Which is localized?

Answer 9

Pediculus is free-moving; phthirus is localized

Question 10

What is the term for lice eggs?

Answer 10

Nits

Question 11

What are a few subjective indications of a lice infestation?

Answer 11

Itching, red eye, insomnia, irritability, occasional preauricular lymphadenopathy

Question 12

What are a few objective indications of a demodex infestation?

Answer 12

Nit cases, crusty lid margins, madarosis, conjunctival injection, lid edema/erythema

Question 13

What are some treatment options for lice infection?

Answer 13

Removal, ocular meds (erythromycin, bacitracin, physostigmine); pediculocidal agents for non-ocular areas; alcohol-coated swab along lid margin, oral ivermectin off-label

Question 14

Which of the pediculocidal agents kills nits?

Answer 14

Ovide