D1.377 - Folic Acid Allergy: A Rare Case

Background

Folic acid belongs to the water-soluble B-complex vitamins and is essential both for nucleotide biosynthesis and for the remethylation of homocysteine. It is particularly important during periods of rapid cell division and growth and is administered as a supplement for the treatment of anemia. It is not a common trigger of hypersensitivity reactions; however, rare cases of mild to severe hypersensitivity reactions have been reported in the literature.

Method

A 32-year-old woman presented for evaluation at the Allergy Department of a tertiary hospital in Athens due to a reported episode of anaphylaxis occurring 30 minutes after taking a folic acid tablet 5 mg (Filicine). The severity of the episode was classified as grade III according to Brown, as she developed acute urticaria and four episodes of vomiting accompanied by dizziness and hypotension, which were confirmed at the Emergency Department where she was admitted. This was the first Filicine dose she had taken during that period due to low folic acid levels, although she had previously received Filicine treatment in the past.

Results

During the diagnostic workup, clinical and laboratory evaluation as well as differential diagnosis of anaphylaxis were performed. Skin prick testing with Filicine was positive (9.5 mm) with a negative control, while total IgE was <15 IU/mL and tryptase was 8.1 μg/L.

Conclusions

Based on the results of the allergological evaluation and the patient’s history, folic acid was considered the causative agent for the hypersensitivity reaction. This case is of particular interest, as there are few similar cases reported in the literature.