Before starting a biologic or conventional systemic immunomodulator for psoriasis, atopic dermatitis or another inflammatory skin disease, screen for latent tuberculosis and viral hepatitis. Immunosuppression can reactivate both, and the screen is quick and cheap relative to the harm it prevents.
Check an interferon-gamma release assay or tuberculin test with a chest radiograph, hepatitis B surface antigen and core antibody, and hepatitis C antibody, alongside a baseline full blood count and liver function. In India, where latent tuberculosis is common, this step is not optional — a missed latent infection can reactivate on anti-TNF and other agents.
Document the result before the first dose, and arrange prophylaxis or specialist input where a screen is positive rather than simply withholding effective treatment.
- Check latent TB (interferon-gamma release assay or tuberculin test plus chest radiograph) before starting.
- Check hepatitis B surface antigen and core antibody, and hepatitis C antibody.
- Take a baseline full blood count and liver function, and record results before the first dose.
- A positive screen means prophylaxis or specialist input, not automatic denial of treatment.
Why it matters
In a high-TB-burden setting, a skipped screen risks reactivation that is far costlier than the test.
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