Povidone Iodine and Allergies

Published: October 1, 2020

ophthalmic surgery 800

Povidone Iodine (PI) is the surgical scrub solution preferred by most ophthalmologists, according to the American Society of Ophthalmic Nurses.(1) PI has been widely used since 1991, when a surgical study showed that use of PI before cataract surgery decreased the rate of endophthalmitis from 0.18% to 0.06%. It is now standard practice to employ PI before surgery as well as prior to intravitreal injections. Important advantages of PI include: a short application time for effectiveness, ability to penetrate biofilm, lack of microbial resistance, and safety to the retina.(2)

The use of intravitreal injections has increased over the last several years, as new treatments for eye diseases such as exudative macular degeneration, retinal vein occlusions, and diabetic retinopathy, rely on medicines delivered intravitreally. (3) “Despite a low incidence of endophthalmitis following intravitreal injections, the prevalence of endophthalmitis is rising due to the sheer volume of intravitreal injections being performed today compared to 10 years ago,” according to a study published in Retinal Physician.(3)

Some patients report they are allergic to iodine and do not want PI used prior to a procedure. This creates a serious clinical dilemma for ophthalmologists who recognize how important the medicine is in preventing a serious infection that can potentially lead to blindness. Many of these patients mistakenly believe they are allergic to iodine because they are allergic to shellfish. According to the American College of Allergy, Asthma, and Immunology, “Years ago doctors believed that shellfish allergy stemmed from increased amounts of iodine present in the shellfish, so patients with a shellfish allergy were told to avoid iodine. If you are allergic to shellfish, specific proteins found in these foods are the allergens, not iodine.”(4)

Still, even though a true allergy to PI is very rare, and anaphylaxis after ophthalmic use has not been reported, physicians hesitate to use the antiseptic if a patient claims an allergy. This unnecessarily increases the risk of post-procedure endophthalmitis, according to an article in the Journal of VitreoRetinal Diseases.(5) The article goes on to say, “Given the infrequency of a true allergy to PI physicians should critically consider any reported reactions to the antiseptic itself. Though an irritant effect is possible, this alone is not a contraindication.”(5)

An ophthalmologist writing for Ophthalmology Web suggests patch testing a patient who presents with a history of topical iodine allergy.(6)


 

(1) American Society of Ophthalmic Registered Nurses, Presurgical Periocular Scrub, Chapter in Procedural Manual.
(2) Grzybowski, A. M.D., Kanclerz, P. M.D., Myers, W. M.D., Current Opinion Ophthalmology, The Use of Povidone-Iodine in Ophthalmology, https://pubmed.ncbi.nlm.nih.gov/
(3) Starr, M. M.D., Bakri, S. M.D., Retinal Physician, Reducing Endophthalmitis Risk Following Intravitreal Injections: What Really Works? https://www.retinalphysician.com/
(4) American College of Allergy, Asthma, and Immunology, Is Shellfish Allergy Related to Iodine? https://acaai.org/
(5) Hinkle, J. M.D., Wikoff, C. M.D., PhD, et. al., Journal of Vitreoretinal Diseases, “Iodine Allergy” and the Use of Povidone Iodine for Endophthalmitis Prophylaxis, https://journals.sagepub.com/
(6) Lee, W. M.D., M.S., Ophthalmology Web, The Myths Regarding Povidone-Iodine Allergy, https://www.ophthalmologyweb.com/