Abstract
Purpose: :
To discuss clinical approaches to two commonly reported allergies. Clinicians frequently withhold the following agents in the context of self-reported "allergy:(1) Povidone-iodine (PI) preparations when patients report an allergy to iodine and/or seafood.(2) β-lactam antibiotics such as cephalosporins when patients report an allergy to penicillin.
Methods: :
Review of medical literature with an emphasis on author-selected studies.
Results: :
PI: Up to 4% of patients can have an irritant effect. This is proportional to the duration of exposure and can result in severe chemical burn if skin or mucus membranes are exposed to PI for long periods of time. Much less commonly, patients can develop a contact dermatitis which develops after an initial sensitizing exposure and subsequent contact. Anaphylaxis to PI is rare, usually attributable to the povidone component and no cases have been reported related to ophthalmic use. Penicillin: In the setting of a confirmed penicillin allergy, cross-reactivity is most likely to occur with first generation cephalosporins and there is negligible cross-reactivity reported for newer generation cephalosporins.
Conclusions: :
(1) When allergy does occur to PI, it is likely against povidone and the iodine component likely plays no role in allergic reactions.(2) Patient reported "seafood" or "Iodine" allergies are generally not contraindication to the use of povidone-iodine.(3) In patients with documented IgE mediated reaction to penicillin, use of cephalosporins with similar side chains (first generation) should be avoided.(4) When treating endophthalmitis emergently in a patient who reports a penicillin allergy, ceftazidime can be safely utilized.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • drug toxicity/drug effects • endophthalmitis