What labs are recommended for individuals experiencing hair loss?

Laboratory Testing for Hair Loss

For most cases of hair loss, laboratory tests are unnecessary, but when the diagnosis is in doubt, specific tests may be indicated based on the suspected underlying cause. 1

Diagnostic Approach to Hair Loss

The evaluation of hair loss should follow a systematic approach:

1. Clinical Assessment

   • Pattern and distribution of hair loss
   • Presence of scalp inflammation or scarring
   • Examination for broken hairs, exclamation mark hairs, or other characteristic findings
   • Dermoscopy to identify yellow dots, dystrophic hairs, or cadaverized hairs

2. Laboratory Testing Based on Suspected Diagnosis

When No Laboratory Tests Are Needed:

• Typical androgenetic alopecia with characteristic pattern
• Clear cases of alopecia areata with typical patches
• Obvious traction alopecia with history of tight hairstyles

When Laboratory Tests Are Indicated:

For suspected alopecia areata with atypical presentation:

• Fungal culture (to rule out tinea capitis)
• Skin biopsy (when diagnosis is uncertain)
• Serology for lupus erythematosus
• Serology for syphilis 1

For suspected telogen effluvium:

• Complete blood count
• Thyroid function tests
• Iron studies (ferritin, iron, TIBC)
• Vitamin D levels
• Zinc levels

For suspected scarring alopecia:

• Scalp biopsy (essential for diagnosis)
• Autoimmune panels if connective tissue disease suspected

Important Considerations

• Iron deficiency testing is not routinely recommended for alopecia areata, as studies have not confirmed a consistent association or treatment response to iron replacement therapy 1

• Autoimmune disease screening is generally not justified for routine cases of alopecia areata despite the increased frequency of autoimmune diseases in these patients 1

• Scalp biopsy should be an early step in evaluation when scarring alopecia is suspected 2, 3

Common Pitfalls to Avoid

1. Overordering laboratory tests for typical presentations of common hair loss conditions

2. Failing to perform a biopsy when cicatricial (scarring) alopecia is suspected

3. Attributing hair loss to iron deficiency without other supporting evidence

4. Missing underlying systemic conditions that may present with hair loss as an early symptom

5. Delaying diagnosis of scarring alopecia, which can lead to permanent hair loss if not treated promptly

The psychological impact of hair loss should not be underestimated, as it can significantly affect quality of life and mental health 1, 4. Proper diagnosis through appropriate testing when indicated is essential for effective management and treatment of the underlying cause.