Essentials of Diagnosis ㅡ Forms of hair loss may be (1) Scarring (suggested by absent follicular markings). (2) Nonscarring (suggested by present follicular markings).

Scarring is irreversible and permanent, thus it is important to treat the scarring process as early as possible and may occur following chemical or physical trauma, bacterial or fungal infections, severe herpes zoster, chronic discoid lupus erythematosus, scleroderma and excessive ionizing radiation. Specific dermatologic diseases of the scalp that result in scarring alopecia include lichen planopilaris, frontal fibrosing alopecia, dissecting cellulitis of the scalp and folliculitis decalvans. The specific cause is often suggested by the history, distribution of hair loss and appearance of the skin, as in lupus erythematosus.
Nonscarring may occur in association with various systemic diseases such as systemic lupus erythematosus, secondary syphilis, hyperthyroidism or hypothyroidism, iron deficiency anemia, vitamin D deficiency and pituitary insufficiency.

In androgenetic alopecia, both men and women are affected, often starting in the third decade. Telogen effluvium is A transitory increase in the number of hairs in the telogen (resting) phase of the hair growth cycle. Alopecia areata (unknown cause) is believed to be an immunologic process (autoimmune). Occasionally associated with Hashimoto thyroiditis, pernicious anemia, Addison disease, and vitiligo.

SYMPTOMS AND SIGNS

Androgenetic alopecia ㅡ In men, the earliest changes occur at the anterior portions of the calvarium on either side of the "widow's peak" and on the crown (vertex). In women, there is retention of the anterior hairline while there is diffuse thinning of the vertex scalp hair and a widening of the part. The extent of hair loss is variable and unpredictable.

Alopecia areata ㅡ Typically, there are patches that are perfectly smooth and without scarring. Tiny hairs 2–3 mm in length, called "exclamation hairs," may be seen. Telogen hairs are easily dislodged from the periphery of active lesions. The beard, brows, and lashes may be involved. Involvement may extend to all of the scalp hair (alopecia totalis) or to all scalp and body hair (alopecia universalis).

DIFFERENTIAL DIAGNOSIS

Scarring (cicatricial). Chemical or physical trauma, lichen planopilaris, bacterial or fungal infection, herpes zoster (shingles) and discoid lupus erythematosus and scleroderma.

Nonscarring. Androgenic (male pattern) baldness, telogen effluvium, alopecia areata or drug-induced alopecia, systemic lupus erythematosus, hyperthyroidism or hypothyroidism, iron deficiency anemia and vitamin D deficiency.

DIAGNOSIS

Laboratory tests ㅡ Serum testosterone, DHEAS, iron, total iron-binding capacity, and thyroid function tests and a complete blood count will identify most other causes of hair thinning in premenopausal women.

Telogen effluvium ㅡ Diagnosed by the presence of large numbers of hairs with white bulbs coming out upon gentle tugging. Counts of hairs lost on combing or shampooing often exceed 150 per day, compared with an average of 70–100.

Diagnostic procedures ㅡ Biopsy is useful in the diagnosis of scarring alopecia, but specimens must be taken from the active border and not from the scarred central zone.

MEDICATIONS

For androgenetic alopecia, minoxidil 5% solution once daily. Minoxidil is available over the counter and recommended for persons with recent onset (< 5 years) and smaller areas of alopecia. Approximately 40% of patients treated twice daily for 1 year will have moderate to dense growth. Hair loss or thinning in women may be treated with topical minoxidil.

Finasteride (Proscar). In men, 1 mg daily orally has similar efficacy to minoxidil. May be added to minoxidil and contraindicated in women who are or may become pregnant, but otherwise may be given in doses up to 2.5 mg/day orally.

Telogen effluvium. If iron deficiency is suspected, a serum ferritin should be obtained, and a low value followed by iron supplementation.

Alopecia areata. Intralesional corticosteroids are frequently effective. Triamcinolone acetonide in a concentration of 2.5–10 mg/mL is injected in aliquots of 0.1 mL at approximately 1- to 2-cm intervals, not exceeding a total dose of 30 mg per month for adults.

THERAPEUTIC PROCEDURES

Scarring: prompt and adequate control of the underlying disorder; usually leads to regrowth of hair.
Alopecia areata: usually self-limiting, with complete regrowth of hair in 80% of patients, but some mild cases are resistant. Support groups for patients with extensive alopecia areata are very beneficial.
Androgenetic alopecia: platelet rich plasma is an emerging therapy.

REFERENCES

Adil, A. and Godwin, M. (2017). The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis. Journal of the American Academy of Dermatology, [online] 77(1), pp.136-141.e5. Available at: https://www.ncbi.nlm.nih.gov/pubmed/28396101
Jones, G., Keuthen, N. and Greenberg, E. (2018). Assessment and treatment of trichotillomania (hair pulling disorder) and excoriation (skin picking) disorder. Clinics in Dermatology, 36(6), pp.728–736
‌Strazzulla, L.C., Wang, E.H.C., Avila, L., Lo Sicco, K., Brinster, N., Christiano, A.M. and Shapiro, J. (2018). Alopecia areata. Journal of the American Academy of Dermatology, 78(1), pp.1–12
Lee, S. and Lee, W.-S. (2017). Management of alopecia areata: Updates and algorithmic approach. The Journal of Dermatology, 44(11), pp.1199–1211. Available at: https://pubmed.ncbi.nlm.nih.gov/28635045
Santos, L.D.N. and Shapiro, J. (2019). What’s New in Hair Loss. Dermatologic Clinics, [online] 37(2), pp.137–141. Available at: https://www.ncbi.nlm.nih.gov/pubmed/30850035

Approach to alopecia