Background and importance The development of skin tests is a booming diagnostic area in detecting the agent responsible for an allergic reaction.
Aim and objectives To describe the development and results of skin tests in the study of anaphylaxis by Trigon depot.
Material and methods A 52-year-old patient presented with generalised pruritus, local irritation and dyspnoea immediately after infiltration of Trigon depot. The allergology department asked the pharmacy department (PD) to prepare intraepidermal (prick test) and intradermal tests with the concentrated drug and serial dilutions of Trigon depot, triamcinolone, carboxymethylcellulose and polysorbate 80. The PD carried out a bibliographic search to determine the physical form of the components, and their physical–chemical characteristics and conservation. There were no specific data on dilutions to these tests, so we relied on Al-Hadithy et al (2011).
The PD evaluated the effectiveness by the results of the skin tests. Possible false positives were taken into account.
Results We manufactured Trigon depot 40 mg/mL prick tests (from commercialised vial), carboxymethylcellulose 5 mg/mL (from commercialised eye drops), triamcinolone 1 mg/mL (from the substance powder using a 0.22 µm filter) and polysorbate 80 (from docetaxel 20 mg/mL). The intradermal syringes of Trigon and carboxymethylcellulose were prepared at serial dilutions of 1:100 and 1:1000, and triamcinolone and polysorbate 80 at dilutions of 1:1, 1:10 and 1:100.
According to good manufacturing practices, the process was carried out in a horizontal laminar flow hood, except for polysorbate 80. Physical stability was evaluated by visual inspection to ensure homogeneity and it was packed in 1 mL syringes stored at 2–8°C for 48 hours protected from light. The results of the study were: negative skin tests for docetaxel (containing polysorbate 80) and triamcinolone; prick test with Trigon depot produced mild erythema; intradermal reaction with Trigon depot (1:100) was clearly positive with a 15×10 mm papule and erythema; and intradermal reaction with carboxymethyl cellulose (1:100) was positive with an 8 mm papule and erythema.
Conclusion and relevance In this multidisciplinary study, doctors and pharmacists have worked towards a common goal, the well being of the patient in the diagnosis of a rare anaphylactic reaction. It was concluded that the patient had undergone anaphylaxis due to carboxymethylcellulose contained in Trigon depot. This excipient is very common in the pharmaceutical industry. In fact, our patient had previously been exposed to Aquacel AG (contains carboxymethylcellulose) which acted as the primary sensitiser.
References and/or acknowledgements No conflict of interest.
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