arly facilitate the therapeutic evaluation of other micronutrients and immunomodulatory compounds.
Zinc cream had no effect in persons with adequate concentrations of zinc; however, persons who were deficient in zinc but otherwise apparently healthy had suppressed skin-test reactions, despite the absence of frank malnutrition; this suppression was reversed by the application of zinc cream. Thus, zinc cream application corrected false-negative TB skin-test reactions caused by zinc deficiency, allowed more sensitive diagnosis, and hence facilitated appropriate treatment of latent TB infection. Topical zinc is a simple and relatively inexpensive method of enhancing reliability of the established TB skin test for diagnosing this neglected disease. This has public health implications because the TB skin test is central to the problematic area of diagnosing TB infection and disease, especially in children who are prone to both zinc deficiency (2,4) and false-negative skin-test results (1). Therefore, the zinc-mediated augmentation of TB skin testing that we have demonstrated may facilitate the diagnosis of adult and pediatric cases of TB in regions where micronutrient deficiency is prevalent.
In conclusion, this study demonstrated that physiologically significant subclinical zinc deficiency was common in this population, that low plasma zinc predicted negative TB skin-test results, and that topical zinc supplementation augmented local antimycobacterial immune responses sufficiently to reverse this anergy of micronutrient deficiency.
Dr Rao is a physician specializing in international public health practice and research.
We thank the volunteers of Susana Higushi community, who generously gave written informed consent to have paired skin tests for medical research; Tom Doherty, Barbara Golden, and Mayuko Saito for helpful discussions; and Katherine Sacksteder for editorial assistance.
C.A.E. and A.R.E. are funded by the Wellcome Trust. C.A.E. and this research were funded in part by the charity Innovation for Health and Development. V.B.R. was funded by the Special Trustees of the Hospital for Tropical Diseases.
- Pelly TF, Santillan CF, Gilman RH, Cabrera LZ, Garcia E, Vidal C, Tuberculosis skin testing, anergy and protein malnutrition in Peru. Int J Tuberc Lung Dis. 2005;9:977–84.
- Golden MH, Harland PS, Golden BE, Jackson AA. Zinc and immunocompetence in protein-energy malnutrition. Lancet. 1978;1:1226–8.
- Lin RY, Busher J, Bogden GJ, Schwartz RA. Topical zinc sulfate augmentation of human delayed type skin test response. Acta Derm Venereol. 1985;65:190–3.
- Cuevas LE, Almeida LM, Mazunder P, Paixao AC, Silva AM, Maciel L, Effect of zinc on the tuberculin response of children exposed to adults with smear-positive tuberculosis. Ann Trop Paediatr. 2002;22:313–9.
- Karyadi E, West CE, Schultink W, Nelwan RH, Gross R, Amin Z, A double-blind, placebo-controlled study of vitamin A and zinc supplementation in persons with tuberculosis in Indonesia: effects on clinical response and nutritional status. Am J Clin Nutr. 2002;75:720–7.
Suggested citation for this article: Rao VB, Pelly TF, Gilman RH, Cabrera L, Delgado J, Soto G, et al. Zinc cream and reliability of tuberculosis skin testing. Emerg Infect Dis [serial on the Internet]. 2007 Jul [date cited]. Available from http://wwwnc.cdc.gov/eid/article/13/7/07-0227
- Page created: June 21, 2010
- Page last updated: June 21, 2010
- Page last reviewed: June 21, 2010
- Centers for Disease Control and Prevention,
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)
Office of the Director (OD)