High-Dose Steroids and PPD Skin Test Readings

Effect of Corticosteroids on PPD Testing

Systemic corticosteroids can suppress delayed-type hypersensitivity reactions, which are the basis of the PPD skin test, leading to false-negative results 1

Doses of prednisolone higher than 10-20 mg per day are more likely to cause significant suppression of PPD skin test reactions 2
Clinical experience suggests that if the daily dose is no higher than 10 mg prednisolone, suppression of positive patch tests is unlikely 2

Tuberculin skin testing should ideally be performed before initiating high-dose corticosteroid therapy whenever possible 1
For patients already on high-dose steroids, consider the increased risk of false-negative results when interpreting PPD tests 3
Alternative testing methods such as interferon-gamma release assays (IGRAs) may be less affected by steroid therapy and should be considered in patients on high-dose steroids 4
Two-step testing may help identify individuals with waning hypersensitivity reactions who might otherwise have false-negative results 5

For patients requiring long-term corticosteroid therapy at doses exceeding 15 mg of prednisone daily for more than 3 weeks, preventive therapy for tuberculosis should be considered if they have a positive tuberculin test or are at high risk 1

In patients on high-dose steroids, consider using IGRAs such as QuantiFERON-TB Gold, which may be less affected by steroid therapy 4
When PPD testing must be done in patients on steroids, consider using anergy testing with companion antigens (e.g., Candida antigen and tetanus toxoid) to help interpret negative PPD results 3