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KembaraXtra- Medicine – Alopecia
Alopecia refers to involuntary hair loss, most commonly affecting the scalp but potentially involving any hair-bearing area of the body. Alopecia is broadly classified into nonscarring (noncicatricial) and scarring (cicatricial) forms. Nonscarring alopecia is characterized by hair loss without permanent follicular destruction, scarring, or skin atrophy, whereas scarring alopecia results in irreversible hair loss due to follicular damage accompanied by inflammation, fibrosis, and loss of follicular openings.
Among nonscarring alopecias, alopecia areata is an autoimmune condition causing patchy hair loss on the scalp, eyebrows, eyelashes, or beard area, and may progress to alopecia totalis (complete scalp hair loss) or alopecia universalis (complete loss of body hair). Androgenetic alopecia (AGA) is the most common form of hair loss and results from genetically determined follicular sensitivity to androgens. In men, it presents as bitemporal recession, frontal thinning, and vertex balding (male pattern hair loss), while in women it manifests as diffuse central scalp thinning with preservation of the frontal hairline (female pattern hair loss). Women may initially notice increased shedding and reduced ponytail volume years before visible thinning develops.
The epidemiology of alopecia varies by etiology. Alopecia areata affects approximately 1% of the U.S. population by age 50 and occurs equally in both sexes. Androgenetic alopecia affects up to 50% of Caucasian men by age 50, with lower prevalence and later onset in Asian and African-American men. By age 70, approximately 40% of women are affected, particularly after menopause. Genetic factors play a significant role, especially in androgenetic alopecia, which is polygenic with variable penetrance, while certain scarring alopecias are more common in individuals with coarse or tightly curled hair.
The causes of alopecia are diverse and include autoimmune disorders, hormonal changes, infections, medications, nutritional deficiencies, physical or psychological stress, and trauma. Nonscarring alopecia may result from altered hair cycling (as in telogen effluvium or anagen effluvium), follicular miniaturization (as in androgenetic alopecia), hair shaft damage (from traction, trichotillomania, or cosmetic overprocessing), or immune-mediated follicular attack (as in alopecia areata). Scarring alopecia may be caused by inflammatory or autoimmune diseases such as lichen planopilaris or discoid lupus erythematosus, infections like severe tinea capitis with kerion formation, neoplasms, or congenital conditions.
Clinical evaluation begins with a thorough history, focusing on the onset, duration, and pattern of hair loss; recent stressors or illnesses; medication use; nutritional status; hair care practices; family history; and associated systemic or dermatologic symptoms. Physical examination assesses the distribution and extent of hair loss, presence of inflammation or scarring, hair shaft abnormalities, and associated findings such as virilization in women or nail changes in alopecia areata. Characteristic findings include exclamation-point hairs in alopecia areata, broken hairs of varying lengths in traumatic alopecia, and shiny atrophic skin with loss of follicular openings in scarring alopecia.
Diagnostic evaluation may include a hair pull test, where removal of six or more hairs from a gentle pull suggests active shedding, most commonly seen in telogen effluvium. Scalp biopsy is essential when scarring alopecia is suspected and should be performed with both vertical and horizontal sections for optimal histopathologic assessment. A trichogram may help quantify the proportion of anagen versus telogen hairs. Laboratory testing is guided by clinical suspicion and may include complete blood count, iron studies, thyroid function tests, autoimmune markers, and hormonal evaluation in women with signs of hyperandrogenism.
The differential diagnosis of nonscarring alopecia includes telogen effluvium, characterized by diffuse shedding following physiologic or psychological stress; androgenetic alopecia, with its characteristic patterned thinning; alopecia areata, presenting with well-demarcated patches of hair loss and autoimmune features; tinea capitis, especially in children; and traumatic alopecia, including traction alopecia and trichotillomania. Scarring alopecias include conditions such as lichen planopilaris, discoid lupus erythematosus, and inflammatory tinea capitis with kerion formation, all of which may lead to permanent hair loss if untreated.
Treatment depends on the underlying cause. Telogen effluvium is typically self-limited, with hair regrowth occurring within months once the inciting factor is removed. Androgenetic alopecia is managed with topical minoxidil in both sexes and oral finasteride in men; discontinuation of therapy results in recurrence of hair loss. Additional options include antiandrogens in selected women, hair transplantation, cosmetic camouflage, and low-level light therapy. Alopecia areata may resolve spontaneously, but treatments include topical, intralesional, or systemic corticosteroids, topical immunotherapy, and newer agents such as oral JAK inhibitors, which are now approved for severe disease in adults. Tinea capitis requires systemic antifungal therapy, and inflammatory kerion may necessitate adjunctive corticosteroids. Traction alopecia improves with elimination of the offending hairstyle or practice, while scarring alopecias focus on early inflammation control to prevent further permanent loss.
Patients with suspected scarring alopecia, treatment-resistant disease, or diagnostic uncertainty should be referred to dermatology. Education and counseling are essential, as hair loss can have a profound psychological impact. For patients with alopecia areata, support organizations and patient education resources can provide valuable guidance and reassurance.
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