Ficus carica is a fruit of the Moraceae family, which is very rarely reported or described as a reason behind food allergy. This study was done with the purpose to describe the first case of fig allergy that occurred as cross-reactivity between fig and Derp 1.

A case of a 10-years-old-girl was understudy, with a history of no-seasonal mild intermittent rhinitis, who experienced an immediate reaction after ingestion of fresh fig. SPT with commercial extracts of food, airborne allergens, latex, and panallergens were performed. SPT revealed a sensitization only for dermatophagoides farina and dermatophagoides pteronyssinus which was then confirmed with by specific IgE assay. We also carried out a positive SPT with a commercial fig allergen and PBP both with skin and pulp of green raw and cooked fig. Fig specific serum IgE levels were 1.08 U/ml and specific IgE for rDer p1 was 16.20 U/ml. In contrast, specific IgE levels for latex, LTP, profilin, PR-10, and pollen allergens were negative.

The study concluded through its findings that the ficin belongs to the cysteine protease family-like Der p 1. The symptoms presented by our patient could be related to cross-reactivity between these two proteins which present a structural homology.

Reference: https://clinicalmolecularallergy.biomedcentral.com/articles/10.1186/s12948-020-00125-6