There are 100 to 150 eyelashes in each upper eyelid, and every eyelash persists for 3 to 5 months before being shed.³ Madarosis may occur as an isolated finding or may be part of a generalized loss of scalp or body hair.¹,²,³,⁴,⁵,⁶,⁷,⁸ The causes may be broadly classified into (1) dermatologic diseases, including alopecia areata, psoriasis, acne rosacea, discoid lupus erythematosus, cutaneous sarcoidosis, telogen effluvium, and en coup de sabre (localized scleroderma); (2) infectious diseases, including staphylococcal blepharitis, herpes simplex or zoster, HIV, and leprosy; (3) endocrine disease including hyper-and hypothyroidism; (4) drugs, including antithyroid drugs, anticoagulants, anticholesterol drugs, and antimetabolites such as cyclophosphamide, colchicine, or methotrexate; (5) trauma, including radiation for ocular tumors, thermal, chemical, or electrical burn, surgical trauma to the eyelids or the brow (direct brow lift), or eyelid tattooing; (6) neoplastic eyelid processes, particularly sebaceous cell carcinoma, squamous or basal cell carcinoma, malignant melanoma of the eyelid, or lymphoma; and least commonly (7) congenital conditions, including eyelid colobomas, cryptophthalmos, Ehlers-Danlos syndrome, acanthosis nigricans, and Treacher Collins syndrome.¹,²,³,⁴,⁵,⁶,⁷ Other atypical causes that cannot be categorized include substance abuse (cocaine vapor), which is associated with reversible madarosis¹,²,⁵; the long-term daily use of mascara⁴; and Kawasaki disease.⁸

Madarosis can also be classified pathogenetically into scarring and nonscarring types, which is a useful tool to determine the prognosis.²,³ In general, any of the above-mentioned conditions can lead to nonscarring madarosis if the inflammation they induce is superficial or transient with no fibrosing potential, whereas scarring or cicatricial madarosis is caused by a deep irreversible fibrotic process.²

A detailed discussion of the entire range of causes of eyelash loss is beyond the scope of this chapter and is detailed elsewhere in the literature,² but the major causes include infections, inflammatory conditions such as rosacea and atopic dermatitis, nutritional deficiencies, trauma, and eyelid margin lesions.

Depending on the etiology, patients with madarosis may report a range of hair loss experiences, from mild thinning to complete eyelash and eyebrow hair loss, as well as a reduction in the length of the remaining eyelashes and a change in color (depigmentation).⁹

Madarosis can be seen in cases of long-standing blepharitis with eyelid margin hypertrophy and scarring (Figure 37.1). Chronic eyelid rubbing can break the lashes at their base resulting in the apparent absence of lashes (Figure 37.2).

Alopecia areata, an autoimmune nonscarring type of hair loss, very rarely involves the eyelids exclusively and is more frequently observed in cases of alopecia totalis (scalp alopecia) or alopecia universalis (whole body alopecia).²,⁹,¹⁰ Within the active patch of alopecia ariata, there is an inflammatory lymphocytic infiltration around the lower third of the eyelash that converts the growth phase of the eyelash from an anagen (growing phase) to a telogen (resting phase).¹⁰ Telogen effluvium is the most common type of hair loss and is defined as an increased shedding of normal telogen hair. It may be associated with several systemic diseases or may occur after severe emotional trauma and rarely involves the brows.¹