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KEY CONCEPTS
The hair cycle consists of three phases: anagen, catagen, and telogen. These are not synchronized across all hair follicles. Different factors regulate each phase of the hair cycle.
Pattern hair loss (or androgenetic alopecia) is an inherited condition in which androgens play a key role.
Inflammation plays an important role in alopecia. Inflammatory infiltrates are evident in androgenetic alopecia and alopecia areata. Alopecia areata is the most frequent cause of inflammation-induced alopecia. Chronic inflammation may lead to the destruction of the hair follicle, resulting in irreversible hair loss.
Scarring hair loss (or cicatricial alopecia) leading to irreversible hair loss can be caused by chronic inflammation or secondary to burns, cancer, trauma, radiation, or other diseases such as lichen planopilaris and chronic cutaneous lupus erythematosus.
Thinning of hair or hair loss is usually the only clinical sign of alopecia. Other symptoms (eg, itching, pain, burning, or prickly discomfort) would suggest other underlying disease conditions. Dermatologic diseases can cause hair loss, which varies from mild, nonscarring, and reversible to scarring and irreversible.
Alopecia can be distressing, affecting the quality of life and causing psychological problems. Psychosocial support and counseling must not be overlooked.
Treatment and management strategies of alopecia should be as cause-specific as possible. Identified causes (eg, iron deficiency, tinea capitis) should be treated and/or eliminated as soon as practically feasible.
Treatment for androgenetic alopecia includes topical minoxidil, oral 5α-reductase inhibitors (finasteride, dutasteride) for men, hormonal therapy for women, and miscellaneous therapies including nutritional supplements and laser light therapy with variable efficacy.
Treatment for alopecia areata includes intralesional corticosteroids, topical corticosteroids, high-dose oral corticosteroids, topical minoxidil, topical immunotherapy, topical and systemic biologic agents (in particular JAK inhibitors), azathioprine and other immunosuppressive agents, and other miscellaneous therapies.
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Patient Care Process for Androgenetic Alopecia
Collect
Patient characteristics (eg, age, sex, pregnancy status if female)
Patient medical history (personal and family)
Patient description of history of the alopecia
Signs associated with severity of androgenetic alopecia (eg, areas of involvement)
Signs or symptoms of other conditions (ie, differential diagnosis—could this be a condition other than androgenetic alopecia? Symptoms such as itching, pain, burning, or prickly discomfort may suggest underlying conditions. If the alopecia is seen in a female, is polycystic ovarian syndrome [PCOS] or congenital adrenal hyperplasia present?)
Assess
Severity of androgenetic alopecia—can quantify using hair counts, hair density measurements, and assessing the areas of involvement
Relevant lab work, if needed (eg, check parameters that would rule out PCOS. Refer to the Acne case in the Casebook for discussion of relevant labs for PCOS.)
Ability/willingness to pay for treatment options
Emotional/psychological concerns
Plan
Determine an appropriate treatment approach or various optional approaches (ie, topical vs systemic pharmacotherapy vs natural health products/nutritional supplements vs other approaches [mesotherapy, low-level laser light therapy, hair restoration surgery, cosmetic coverings]). Determine if psychosocial support is needed.
Discuss with the patient various options to determine the most appropriate ...