What is the cause of alopecia in an 18-year-old female, with laboratory testing?

From the Guidelines

For an 18-year-old female experiencing hair loss, I strongly recommend comprehensive laboratory testing including complete blood count, thyroid function tests (TSH, free T3, free T4), ferritin, vitamin D, zinc levels, and sex hormone panel (testosterone, DHEAS, androstenedione) to identify the underlying cause of hair loss. The most common causes of hair loss in young women include iron deficiency, thyroid disorders, polycystic ovary syndrome (PCOS), and telogen effluvium from stress or illness 1.

Key Laboratory Tests

• Complete blood count to rule out anemia or other blood-related disorders
• Thyroid function tests to assess for thyroid disorders, which are a common cause of hair loss in young women
• Ferritin levels to evaluate iron stores, as iron deficiency is a known cause of hair loss, particularly in women 1
• Vitamin D, zinc levels, and sex hormone panel to assess for deficiencies or imbalances that may contribute to hair loss

Importance of Early Intervention

Early intervention is crucial in addressing hair loss, as prolonged hair loss can become more difficult to reverse. Ferritin levels should ideally be above 50 ng/mL for optimal hair growth, even if technically within normal range. If PCOS is suspected, additional testing for insulin resistance with fasting glucose and insulin levels would be appropriate. Vitamin deficiencies, particularly vitamin D, biotin, and zinc, can contribute to hair loss and should be corrected if identified 1.

Treatment Options

Treatment will depend on the underlying cause of hair loss but may include:

• Iron supplementation (typically ferrous sulfate 325mg daily) if iron deficiency is identified
• Thyroid medication if a thyroid disorder is diagnosed
• Anti-androgen therapy such as spironolactone 50-200mg daily if androgen excess is identified
• Correction of vitamin deficiencies, such as vitamin D, biotin, or zinc, if identified as contributing to hair loss. A scalp biopsy may be necessary if laboratory testing is inconclusive.

From the Research

Hair Loss in 18-Year-Old Female

Lab Testing

• Lab testing for hair loss in an 18-year-old female may include evaluation of serum ferritin, thyroid-stimulating hormone, vitamin D, and zinc levels 2.
• A study found that the most common vitamin deficiency in alopecia patients was ferritin (6.5%) 2.
• However, another study suggested that vitamin supplementation may not lead to improved outcomes in non-scarring alopecia, thus limiting the utility of laboratory testing 2.
• Serum iron and ferritin levels have been studied in relation to alopecia areata, with some studies finding lower mean ferritin levels in patients with androgenetic alopecia and alopecia areata compared to normals 3.
• However, other studies have found no significant association between serum iron and ferritin levels and alopecia areata 4, or between serum ferritin and thyroid-stimulating hormone levels and androgenetic alopecia in male patients 5.

Common Causes of Hair Loss

• Common causes of hair loss in females include androgenetic alopecia, alopecia areata, telogen effluvium, and trichotillomania 6.
• Androgenetic alopecia can be diagnosed clinically and treated with minoxidil 6.
• Alopecia areata is diagnosed by typical patches of hair loss and is self-limited 6.
• Telogen effluvium is a nonscarring, noninflammatory alopecia of relatively sudden onset caused by physiologic or emotional stress 6.

Diagnosis and Treatment

• Nonscarring alopecias can be readily diagnosed and treated in the family physician's office 6.
• Scarring alopecia is best evaluated by a dermatologist 6.
• Treatment for hair loss depends on the underlying cause and may include medication, supplementation, or other therapies 6, 2.