A case report of carboxymethylcellulose allergy: exploring tolerance based on administration route

The management of hypersensitivity to excipients and food additives remains a significant issue for healthcare professionals and patients. Avoiding carboxymethylcellulose (CMC) can be a considerable challenge for patients allergic to CMC due to its widespread use. We assessed the tolerance of CMC through different route of administration in a patient with a confirmed CMC allergy. We conducted a literature review to analyze all relevant cases of patients allergic to CMC, focusing on tolerance through non-injectable routes. Skin tests, basophil activation tests, oral and nasal provocation tests with CMC were performed to evaluate patient’s hypersensitivity. Skin tests and basophil activation tests with CMC were positive and confirmed IgE-mediated hypersensitivity to CMC in the patient. While the patient tolerated oral administration of CMC and CMC-containing eye drops, nasal provocation test resulted in asthma exacerbation and rhinitis. Tolerance of CMC appears to be route-dependent. Provocation tests with CMC through various routes of administration are essential for assessing tolerance and providing appropriate recommendations for patients with CMC allergy.