D2.63 - Immediate Hypersensitivity to Chlorhexidine: A Case Series

Chlorhexidine Digluconate is a topical antiseptic increasingly used both in home and hospital settings, with its use rising significantly following the COVID-19 pandemic. Currently, there is no prevalence data on chlorhexidine sensitization in the pediatric population. However, in the general European population, the prevalence is estimated at 1%.

We present a case series of four school-aged pediatric patients (5, 7, 10, and 11 years old) with suspected IgE-mediated hypersensitivity to chlorhexidine. The clinical suspicion was based on exclusive cutaneous involvement, characterized by the immediate appearance of generalized urticarial wheals following the application of topical chlorhexidine in outpatient settings. The 5-year-old patient had previously experienced generalized urticaria and eyelid edema immediately after a surgical procedure in which chlorhexidine was used as an antiseptic.

Skin tests were conducted, including epidermal (prick test with chlorhexidine 5 mg/mL) and intradermal testing (intradermal reaction with chlorhexidine 0.002 mg/mL). 

All four patients tested positive, exhibiting generalized urticarial reactions during testing. Additionally, the 7-year-old patient developed wheals at the specific site where chlorhexidine had been applied for wound care several years earlier, a phenomenon known as “tissue memory.” Specific IgE testing for chlorhexidine was performed in three patients, with results >0.35 kUA/L in all cases.

Subsequently, three of the four patients underwent skin testing with 10% povidone-iodine (prick test and intradermal reaction with a 1:1000 dilution), yielding negative results in all three cases. A controlled exposure test on healthy skin with 10% povidone-iodine and patch testing using the GEIDAC standard series are planned.

In patients with IgE-mediated hypersensitivity to chlorhexidine, it is essential to rule out sensitization to other topical antiseptics, such as povidone-iodine, to provide a safe alternative for these patients.