What are the causes and treatment options for hair loss in a 20-year-old female with no known underlying severe medical conditions?

Hair Loss in a 20-Year-Old Female: Causes and Treatment

Most Likely Causes in This Age Group

The most common causes of hair loss in a 20-year-old woman are androgenetic alopecia (pattern hair loss), telogen effluvium (stress-induced shedding), and alopecia areata (autoimmune patchy hair loss), with nutritional deficiencies playing an important contributing role. 1

Primary Diagnostic Considerations

Androgenetic Alopecia (Pattern Hair Loss)

• Presents as progressive thinning over the vertex and upper parietal scalp with frontal hairline preservation 2
• Most common form of hair loss overall, affecting up to 40% of healthy women by reproductive age 3
• Diagnosis is clinical based on the characteristic pattern 4
• Related to sensitivity to dihydrotestosterone (DHT) causing follicular miniaturization 5

Telogen Effluvium (Stress-Induced Shedding)

• Diffuse hair shedding triggered by physiologic or emotional stressors (illness, surgery, rapid weight loss, severe emotional stress) 5
• Hair follicles are pushed prematurely into the resting (telogen) phase 5
• Self-limited once the precipitating cause is removed 4
• Dermoscopy shows absence of yellow dots and exclamation mark hairs, distinguishing it from alopecia areata 5

Alopecia Areata (Autoimmune)

• Patchy, non-scarring hair loss mediated by T lymphocytes attacking hair follicles 5
• Characterized by exclamation mark hairs (short broken hairs) around expanding patches 6, 5
• About 20% have a family history, indicating genetic susceptibility 6, 5
• Associated with other autoimmune diseases (thyroid disease, vitiligo, lupus) 5
• Spontaneous remission within 1 year occurs in 34-50% of cases 6, 5

Diagnostic Approach

Clinical Examination Essentials

Pattern Recognition

• Diffuse thinning at the crown with frontal hairline preservation suggests androgenetic alopecia 5
• Patchy loss with exclamation mark hairs is pathognomonic for alopecia areata 5, 7
• Assess whether hair can be easily pulled out (positive pull test indicates active disease) 5, 7

Dermoscopy - The Single Most Useful Tool

• Dermoscopy is the most valuable non-invasive diagnostic tool to differentiate between diffuse alopecia areata, telogen effluvium, and androgenetic alopecia 5
• Yellow dots and exclamation mark hairs are pathognomonic for alopecia areata 5
• Their absence is characteristic of telogen effluvium and androgenetic alopecia 5

Targeted Laboratory Testing

Essential Tests for Young Women

• Serum ferritin: Iron deficiency is the most common nutritional deficiency worldwide and a sign of chronic diffuse telogen hair loss 5
• Vitamin D level: 70% of alopecia areata patients have deficiency (<20 ng/mL) versus 25% of controls, with lower levels correlating inversely with disease severity 5
• TSH: Rule out thyroid disease, which commonly causes hair loss 5
• Serum zinc: Tends to be lower in alopecia areata patients, particularly those with resistant disease >6 months 5

Additional Tests When Indicated

• Total testosterone, free testosterone, and SHBG if signs of androgen excess (acne, hirsutism, irregular periods) suggest PCOS 5
• Prolactin level if hyperprolactinemia is suspected 5
• Fungal culture if tinea capitis (scalp ringworm) is suspected 6, 5
• Scalp biopsy only if diagnosis remains uncertain after clinical examination and dermoscopy 5

Treatment Algorithm

For Androgenetic Alopecia (Pattern Hair Loss)

First-Line Treatment

• Topical minoxidil is the FDA-approved first-line treatment for female pattern hair loss 4, 8
• Apply to affected areas of the scalp 4
• Note: Oral finasteride is NOT appropriate for women of reproductive age 1

For Alopecia Areata

Limited Patchy Disease (<50% scalp involvement)

• Intralesional corticosteroid injections are first-line treatment with the strongest evidence (Strength B, Quality III) 5
• 34-50% recover spontaneously within one year, making observation reasonable for very limited disease 6, 5

Extensive Patchy Disease

• Contact immunotherapy is the best-documented treatment, though response rates are lower in severe cases 5
• Consider referral to dermatology for specialized treatment 5

For Telogen Effluvium

Management Strategy

• Identify and remove the precipitating cause (stress, illness, nutritional deficiency) 4
• Hair typically regrows once the trigger is eliminated 4
• Self-limited disorder requiring primarily supportive care 8

Nutritional Supplementation

Vitamin D Supplementation

• Supplement if levels <20 ng/mL according to general international recommendations for adults 5
• No double-blind trials yet exist examining oral supplementation specifically for alopecia areata, but correction of deficiency is recommended 5

Iron Supplementation

• Correct iron deficiency based on ferritin levels 5
• Iron deficiency is strongly associated with chronic diffuse telogen hair loss 5

Zinc Supplementation

• Consider supplementation when deficient, particularly in alopecia areata and telogen effluvium 5
• Zinc serves as a cofactor for multiple enzymes involved in hair follicle function 5

Critical Pitfalls to Avoid

Diagnostic Errors

• Do not order excessive laboratory tests when the diagnosis is clinically evident through pattern recognition and dermoscopy 5
• Do not confuse trichotillomania (compulsive hair pulling) with alopecia areata; trichotillomania shows incomplete hair loss with firmly anchored broken hairs that remain in anagen phase 6, 5
• Do not miss tinea capitis, which requires fungal culture for diagnosis and oral antifungal treatment 6, 5

Management Oversights

• Do not overlook the psychological impact of hair loss, which can cause considerable psychological and social disability warranting assessment for anxiety and depression 5, 1
• Do not fail to assess for signs of androgen excess (PCOS) in women with irregular periods, acne, or hirsutism 5
• Do not ignore the association with other autoimmune diseases, particularly thyroid disease 5, 7

Treatment Considerations

• Avoid excessive supplementation, especially with biotin, due to potential diagnostic test interferences 3
• Remember that many cases of alopecia areata are self-limited, with spontaneous remission making observation reasonable for limited disease 6, 5
• Recognize that childhood onset and ophiasis pattern (scalp margin involvement) carry poorer prognoses in alopecia areata 5