What blood work can I have done to investigate the causes of balding?

Blood Work for Investigating Causes of Balding

For patients experiencing hair loss, laboratory testing should include serum ferritin, vitamin D, zinc, and folate levels to help diagnose nutritional deficiencies that may contribute to balding. 1

Primary Types of Hair Loss and Recommended Blood Tests

• Androgenetic alopecia (pattern hair loss) is the most common cause of hair loss in women and can be related to sensitivity to dihydrotestosterone (DHT) 2
• Alopecia areata is an autoimmune condition characterized by patchy, non-scarring hair loss and is associated with other autoimmune diseases 1
• Laboratory tests for common causes of hair loss should include:
  • Complete blood count (CBC) to evaluate for anemia or infection 3
  • Serum ferritin to assess iron stores 3
  • Thyroid stimulating hormone (TSH) to rule out thyroid disease 4, 3
  • Vitamin D 25OH levels 3
  • Zinc levels, as deficiency is associated with hair loss 1
  • Folate levels, as deficiency may contribute to hair loss 1

Additional Tests Based on Clinical Presentation

• For women with signs of androgen excess (acne, hirsutism, irregular periods):

  • Total testosterone or bioavailable/free testosterone levels 4
  • Sex hormone binding globulin (SHBG) levels 4
  • Consider testing for polycystic ovary syndrome (PCOS) which can cause hair loss 4

• For suspected autoimmune conditions:

  • Antinuclear antibodies (ANA) if systemic lupus erythematosus is suspected 1, 5
  • Serology for lupus erythematosus when it's in the differential diagnosis 1

• For other potential causes:

  • Prolactin level if hyperprolactinemia is suspected 4
  • Two-hour oral glucose tolerance test if diabetes or insulin resistance is suspected 4
  • Fasting lipid and lipoprotein levels to assess for dyslipidemia 4

When to Consider Additional Testing

• Laboratory testing is often unnecessary for common causes of hair loss that can be diagnosed clinically 6
• Additional tests should be considered when:
  • The diagnosis is uncertain or presentation is atypical 1
  • There are signs of systemic disease 7
  • Scarring alopecia is suspected (may require skin biopsy) 1, 3
  • Fungal infection is suspected (fungal culture) 1

Common Pitfalls to Avoid

• Ordering excessive laboratory tests when the diagnosis is clinically evident 1
• Failing to consider the psychological impact of hair loss, which may warrant assessment for anxiety and depression 1, 7
• Overlooking dermoscopy as a non-invasive diagnostic tool that can provide valuable information before resorting to laboratory testing 1
• Not considering that most cases of hair loss are due to common causes like androgenetic alopecia, telogen effluvium, or alopecia areata, which may not require extensive testing 6, 7

Diagnostic Algorithm

1. Determine if the hair loss is scarring or non-scarring (may require dermoscopy or biopsy) 1, 3
2. For non-scarring alopecia:
   • Start with basic blood work: CBC, ferritin, TSH, vitamin D, zinc, and folate 3, 1
   • If signs of hormonal imbalance are present, add testosterone, SHBG, and prolactin 4
3. For scarring alopecia:
   • Consider skin biopsy 1, 3
   • Add autoimmune markers if clinically indicated 1
4. For suspected fungal infections:
   • Perform fungal culture 1