What are the causes and treatment options for alopecia?

Causes and Treatment Options for Alopecia

Alopecia is primarily caused by autoimmune factors, genetic predisposition, and hormonal influences, with treatment options ranging from observation to topical medications depending on the type and severity of hair loss.

Types and Causes of Alopecia

Alopecia Areata

• Characterized by well-defined patches of non-scarring hair loss without epidermal changes 1
• Autoimmune disease mediated by T lymphocytes attacking hair follicles 2, 3
• Genetic predisposition is multifactorial, involving major histocompatibility complex, cytokine and immunoglobulin genes 2
• Often associated with other autoimmune diseases 2, 3
• Lifetime risk in general population is approximately 1.7%, with 60% of patients experiencing onset before age 20 1

Androgenetic Alopecia

• Most common form of alopecia with prevalence of 23-87% 4
• Affects approximately 50% of white males by age 50 5, 6
• Characterized by progressive miniaturization of hair follicles 5
• Requires genetic predisposition coupled with sufficient circulating androgens 5
• Involves transformation from long growth (anagen) and short rest (telogen) cycles to long rest and short growth cycles 5
• Androgen receptor gene has been identified as a contributing factor 5

Diagnostic Approach

Clinical Features to Look For

• Alopecia areata: well-defined patches of hair loss, "exclamation mark" hairs at periphery of lesions 2, 1
• Dermoscopy can aid diagnosis by showing regular round yellow dots in areas of hair loss and dystrophic hairs with fractured tips 2
• Differential diagnosis includes:
  • Trichotillomania: incomplete hair loss with firmly anchored broken hairs 2
  • Tinea capitis: inflamed scalp, often with scaling 2
  • Early scarring alopecia 2
  • Telogen effluvium 2
  • Anagen effluvium (drug-induced) 2
  • Systemic lupus erythematosus 2
  • Secondary syphilis 2

Investigations

• Most cases of alopecia areata do not require investigations 2
• When diagnosis is uncertain, consider:
  • Fungal culture for suspected tinea capitis 2
  • Skin biopsy for suspected scarring alopecia or uncertain diagnosis 2, 7
  • Serology for lupus erythematosus or syphilis if clinically indicated 2, 7
• Routine screening for autoimmune diseases is generally not justified despite increased frequency in alopecia areata patients 2
• Iron deficiency testing is not routinely recommended 2

Treatment Options

Alopecia Areata Treatment

No Treatment

• Legitimate option for many patients, especially those with limited patchy hair loss of short duration 2
• Spontaneous remission occurs in up to 80% of patients with limited patchy hair loss of short duration (<1 year) 2
• Consider "watch-and-wait" approach with reassurance that regrowth cannot be expected within 3 months of patch development 2, 1

Topical Treatments

• Potent topical corticosteroids are widely used but have limited evidence of efficacy 2
• Minoxidil may be used alone or in combination with other treatments 1, 6

Intralesional Treatments

• Intralesional corticosteroids (e.g., triamcinolone acetonide 5-10 mg/mL) stimulate hair regrowth at injection sites 2
• Most suitable for treating patchy hair loss of limited extent 2
• In one study, 62% of patients achieved full regrowth with monthly injections, with better response in those with fewer than five patches of <3 cm diameter 2
• Skin atrophy is a consistent side effect 2

Emerging Treatments

• IL-31 antibodies and 308-nm Excimer laser show promise as novel treatments 1

Androgenetic Alopecia Treatment

FDA-Approved Medications

• Finasteride: Oral medication that inhibits 5α-reductase, effective for male pattern hair loss 8, 6
  • Potential side effects include sexual dysfunction that may continue after discontinuation 8
• Minoxidil: Topical solution (5% for men) that reactivates hair follicles to stimulate regrowth 9, 6
  • Results may be seen as early as 2 months but may take at least 4 months for some men 9
  • Initial increased hair loss may occur for up to 2 weeks as part of the process 9

Combination Therapy

• Combination of finasteride and minoxidil leads to best results in suitable candidates 6
• Hair restoration surgery may be considered in combination with medical treatment 6

Psychological Considerations

• Alopecia can have serious psychological effects despite no direct impact on general health 2
• Patients may experience anxiety, depression, and social difficulties 2, 3
• Psychological support and contact with patient support groups can help individuals cope 2, 7
• Children with alopecia may require referral to pediatric clinical psychologist, educational psychologist, or social worker if showing significant behavioral changes 2

Treatment Pitfalls and Caveats

• No treatment has been shown to alter the long-term course of alopecia areata 2
• Prognosis for long-standing extensive alopecia is generally poor 2
• Patients should be warned about possible relapse following or during initially successful treatment 2
• Hazardous treatments with unproven efficacy should be avoided 2
• For androgenetic alopecia, treatments are variable in effectiveness and work best when started early 5