Background: Narrowband UVB (NBUVB) phototherapy is the cornerstone treatment for vitiligo. Before its initiation, some experts recommend antinuclear antibody (ANA) screening out of concern for either photosensitivity to NBUVB or autoimmune disease exacerbation during treatment. As vitiligo is considered an autoimmune disorder, ANAs can be positively found in the disease without any clinical importance. The necessity for ANA investigations for pre-phototherapy vitiligo patients is therefore questioned.
Methods: We conducted a retrospective study to investigate vitiligo patients who had been checked for ANA before commencing NBUVB phototherapy. Demographic data-including vitiligo type and age of onset-were collected. Samples of ANA, anti-thyroglobulin, and anti-thyroid peroxidase were obtained. The phototherapy treatment protocol and cutaneous reactions to the phototherapy were also recorded.
Results: Among 85 Thai vitiligo patients, the ANA prevalence was 35.3%. The speckled ANA pattern was the most common, and the large majority of patients (80%) had a titer of ≤1:100. Factors associated with positive ANA were female gender and positive anti-thyroglobulin. There were no statistical differences between the phototoxic reactions or phototoxic doses of NBUVB of the ANA-positive vitiligo and ANA-negative vitiligo groups. No cases of SLE were detected in ANA-positive group.
Conclusions: ANA positivity was not correlated with the incidence or dose of phototoxic reaction in phototherapy treated vitiligo, and it may not a predictive factor for SLE diagnosis in vitiligo. ANA might therefore not need to be routinely checked in pre-phototherapy in vitiligo, unless there are clinical suspicions of an autoimmune disease. However, ANA might be involved in part of the cutaneous photoadaptation response to phototherapy.
Keywords: ANA; antinuclear antibodies; narrowband UVB; phototherapy; vitiligo.
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