What blood tests are considered for patients with vitiligo?

Blood Tests in Vitiligo

Thyroid function testing should be performed in all patients with vitiligo due to the high prevalence of autoimmune thyroid disease, which occurs in approximately 34% of adults with this condition. 1

Essential Blood Test

Thyroid Function Testing

• Thyroid-stimulating hormone (TSH) is the primary recommended blood test for vitiligo patients 1
• The British Journal of Dermatology guidelines specifically recommend checking thyroid function given the strong association between vitiligo and autoimmune thyroid disease 1, 2
• TSH abnormalities were found in 3.7% of vitiligo patients without a prior history of hypothyroidism 3
• Thyroid peroxidase antibodies were elevated in almost half of tested vitiligo patients 4

Additional Blood Tests to Consider

Complete Blood Count and Vitamin B12

• Hemoglobin and vitamin B12 levels should be considered to screen for pernicious anemia 3
• Pernicious anemia occurs in 1.3% of vitiligo patients, representing a significant increase over general population prevalence 3
• However, hemoglobin and vitamin B12 were decreased in only 0.3% of patients without a history of pernicious anemia, suggesting lower yield than thyroid testing 3

Antinuclear Antibody (ANA)

• ANA testing may be considered given that 41% of vitiligo patients had elevated antinuclear antibody levels 4
• This reflects the broader autoimmune nature of vitiligo and potential associations with other autoimmune conditions 5

Clinical Context for Testing

High-Risk Associations

• Hypothyroidism is present in 12-23% of vitiligo patients depending on the study population 3, 4
• Other autoimmune comorbidities occur in 23% of vitiligo patients overall, with thyroid disorders being the most common 4
• The autoimmune connection is particularly strong in generalized (non-segmental) vitiligo compared to segmental forms 6

Important Caveats

• The diagnosis of vitiligo itself is primarily clinical and does not require blood tests when the presentation is classical 1
• Blood testing is for screening associated autoimmune conditions, not for diagnosing vitiligo 2
• Atypical presentations may require dermatologist assessment rather than additional laboratory work 1

Practical Testing Algorithm

For all newly diagnosed vitiligo patients:

1. Order TSH as the single most important screening test 1, 2
2. Consider adding thyroid peroxidase antibodies if TSH is abnormal or borderline 4
3. Consider CBC and vitamin B12 if there are clinical signs of anemia 3
4. Consider ANA if there are symptoms suggesting other autoimmune diseases 4

Common pitfall to avoid: Failing to screen for thyroid disease can miss an important treatable condition that affects one-third of vitiligo patients 2