What are the common causes of hair loss in postmenopausal women over 50?

Hair Loss in Women Over 50

The most common cause of hair loss in postmenopausal women over 50 is female pattern androgenetic alopecia, which affects over 50% of this population and presents with diffuse thinning over the mid-frontal scalp and crown while preserving the frontal hairline. 1, 2

Primary Causes

Androgenetic Alopecia (Female Pattern Hair Loss)

• This is the predominant cause, affecting up to 50% of women over their lifetime, with prevalence increasing significantly with advancing age. 3, 4
• The condition results from androgen-dependent hair follicle miniaturization within follicular units, reducing the number of terminal hairs per unit. 4
• Clinical presentation shows diffuse rarefaction over the mid-frontal scalp and crown with an intact frontal hairline, without inflammation or scarring. 2, 4
• Unlike male pattern baldness, women rarely develop complete baldness because not all hairs within follicular units miniaturize simultaneously. 4

Hormonal Changes

• Postmenopausal hormonal shifts can trigger telogen effluvium, causing diffuse hair shedding that typically begins 1-3 months after hormonal changes. 5
• Women with signs of androgen excess (acne, hirsutism, irregular periods) should be evaluated for hyperandrogenism and polycystic ovary syndrome. 6, 3

Nutritional Deficiencies

• Iron deficiency (low serum ferritin) is the most common nutritional deficiency worldwide and a key sign of chronic diffuse telogen hair loss. 6
• Vitamin D deficiency (<20 ng/mL) shows strong association with hair loss, with 70% of alopecia areata patients deficient versus 25% of controls. 6
• Zinc deficiency impairs hair follicle function, with serum levels tending to be lower in patients with hair loss. 6
• Folate deficiency may also contribute to hair loss. 6

Autoimmune Causes

• Alopecia areata presents with patchy, non-scarring hair loss mediated by T lymphocytes attacking hair follicles. 6
• Approximately 20% have a family history, and the condition associates with thyroid disease, lupus, and vitiligo. 6
• Dermoscopy reveals yellow dots, exclamation mark hairs, and cadaverized hairs. 6

Thyroid Dysfunction

• Both hypothyroidism and hyperthyroidism can cause hair loss in this age group. 6
• TSH screening is essential to rule out thyroid disease as a contributing factor. 6

Stress-Related Hair Loss

• Telogen effluvium occurs when physiologic or emotional stressors (illness, surgery, severe emotional stress, rapid weight loss) push hair follicles prematurely into the resting phase. 6
• This typically resolves within 3-6 months once the triggering factor is addressed. 5

Medication-Induced Hair Loss

• Chemotherapy causes anagen effluvium with rapid, severe hair loss. 6
• Other medications including anticoagulants and beta-blockers can trigger hair loss. 6

Diagnostic Approach

Clinical Examination

• Dermoscopy is the single most useful non-invasive tool to differentiate between androgenetic alopecia, telogen effluvium, and alopecia areata. 6
• Look for hair pattern: diffuse thinning at crown with frontal hairline preservation indicates androgenetic alopecia, while patchy loss suggests alopecia areata. 6
• Check for exclamation mark hairs (pathognomonic for alopecia areata) and nail changes (pitting, ridging occur in 10% of alopecia areata patients). 6

Laboratory Testing Algorithm

• Check serum ferritin first, as iron deficiency is the most common nutritional cause. 6
• Measure TSH to rule out thyroid disease. 6
• Test vitamin D levels, as deficiency correlates inversely with disease severity. 6
• Consider zinc levels, particularly if hair loss is resistant to treatment >6 months. 6
• In women with signs of androgen excess, test total or free testosterone, SHBG, and consider evaluation for PCOS. 6, 3
• Check prolactin if hyperprolactinemia is suspected. 6

When to Biopsy

• Skin biopsy is reserved for difficult cases, early scarring alopecia, or diffuse alopecia areata that is challenging to diagnose clinically. 6
• Most cases of androgenetic alopecia and alopecia areata can be diagnosed clinically without biopsy. 6

Common Pitfalls to Avoid

• Do not order excessive laboratory tests when the diagnosis is clinically evident—androgenetic alopecia is typically diagnosed based on pattern and dermoscopy. 6
• Avoid delaying treatment initiation, as early treatment is more effective at arresting progression than stimulating regrowth. 7, 4
• Do not overlook the psychological impact, which may warrant assessment for anxiety and depression. 6
• Remember that 34-50% of alopecia areata cases recover spontaneously within one year, making observation reasonable for limited disease. 6
• Avoid excessive supplementation, especially with biotin, due to potential diagnostic test interferences. 1