Eyelash Trichomegaly (2024)

PMCID: PMC4533537

Sandeep Kaur and Bharat Bhushan Mahajan

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Eyelash growth

During embryological development, eyelashes are the first terminal hairs to appear. Their growth cycle lasts approximately 5-6 months, with a very short anagen phase (30 days) and a relatively long telogen phase (approximately 4-5 months).[1] Eyelashes and eyebrows have the lowest ratio of anagen to telogen hair follicles, with approximately 50% of eyelashes in the anagen phase compared with 85–90% of scalp hairs.

The epidermal growth factor receptor appears to play a crucial role in hair growth as evidenced by drugs that inhibit its function. In addition, prostaglandins have been shown to be able to convert the hair follicle from the telogen phase into the anagen phase.[5]

Congenital conditions associated with eyelash trichomegaly

Among various congenital conditions associated with eyelash trichomegaly [Table 1], only two include it as a defining diagnostic feature: Oliver-McFarlane syndrome and Cornelia de Lange syndrome.

Acquired conditions associated with eyelash trichomegaly

In HIV trichomegaly has been observed to occur in association with late-stage disease. Eyelash length has been shown to normalize as patients respond to anti-retroviral therapy.[13] However, no association has been seen between the length of eyelashes and either the severity or prognosis of HIV infection. Acquired conditions associated with eyelash trichomegaly is mentioned in [Table 2].

Drugs associated with eyelash trichomegaly

1. Prostaglandin analogues like latanoprost, bimatoprost: Most commonly reported cause of eyelash trichomegaly.

2. Epidermal growth factor receptor inhibitors: cetuximab,[14] Panitumumab; tyrosine kinase inhibitors: erlotinib,[15] gefitinib[16]

3. Interferon-α2b[17]

4. Zidovudine

5. Phenytoin

6. Diazoxide, minoxidil

7. Acetazolamide

8. Cyclosporine, tacrolimus

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9. Topiramate

10. Psoralens

11. Corticosteroids

12. Streptomycin

13. Penicillamine

Epidermal growth factor receptor inhibitors

Epidermal growth factor receptor inhibitors are used to treat a variety of solid tumors like bladder, breast, colorectal, head and neck, lung, and ovarian cancers. There are two classes of drugs that target the epidermal growth factor receptor: monoclonal antibodies that block the receptor itself (cetuximab, panitumumab) and small molecules that inhibit the tyrosine kinase activity, thereby blocking receptor activation (gefitinib, erlotinib).

Trichomegaly induced by EGFR inhibitors, a result of enhanced terminal differentiation, usually occurs after 2-5 months of treatment, and can be associated with hypertrichosis in other areas.

The cutaneous adverse effects of these agents have been grouped into a condition known as PRIDE (papulopustules and/or paronychia, regulatory abnormalities of hair growth, itching, and dryness due to epidermal growth factor receptor inhibitors) syndrome.[18]

The authors postulated that, in a similar way that the presence of erlotinib-induced rash has been correlated with tumor response, the presence of eyelash trichomegaly might also be used as a useful clinical tool to assess for antineoplastic therapy success.[19]

Interferon alpha

The first report of interferon-associated eyelash trichomegaly was in two patients with B-cell lymphoma treated with interferon.[20] After 4 months of treatment, both patients began to note that their eyelashes had thickened, curled, and reached lengths of 20–65 mm.

Prostaglandins

Acquired eyelash trichomegaly has been reported with topical use of latanoprost. The effects of prostaglandin F2-alpha and latanoprost have been found to stimulate not only murine hair follicles and follicular melanocytes but also the conversion from telogen to anagen phase. This side effect has also been tried for cosmetic effects. The Food and Drug Administration approved bimatoprost 0.03% solution for treatment of patients with hypotrichosis of the eyelashes in December 2009.[21]

Approach to the patient with eyelash trichomegaly

This should include an overall evaluation of the patient's history and other concurrent medical problems.

The onset of eyelash trichomegaly is an important point for delineating a specific etiology. If present from birth, one should look for other hair anomalies or facial features that may be present (such as alopecia, synophrys) and may suggest one of the congenital syndromes described earlier.

If onset is in later life, one should focus on medications or topical products and a risk assessment for HIV or hepatitis virus should be made.

Treatment

The main treatment of eyelash hypertrichosis involves regular trimming of the eyelashes if they cause symptoms.[22] Sometimes antibiotics and artificial tears may be necessary for local irritation or meibomitis.[23]