000137 - Fig allergy

Moraceae is a family within the order Rosales, comprising approximately 1,250 species. This family includes well-known plants such as the common fig (Ficus carica), banyan, breadfruit, jackfruit, mulberry, and Osage orange.

The most frequent clinical manifestation associated with fig exposure is phytophotodermatitis, while IgE-mediated reactions are reported far less commonly.

We present the case of a 50-year-old woman with a history of moderate allergic rhinitis due to house dust mites. Immediately after the ingestion of a fig, she developed tongue angioedema and oral pruritus. Symptoms resolved after treatment with antihistamines and corticosteroids. She reports no reactions to other foods or to latex.

An allergological work-up was performed, including standard aeroallergens, panallergens (lipid transfer proteins and profilin), latex, kiwi, avocado, papaya, banana, and pineapple. Skin testing was positive for fig and Dermatophagoides pteronyssinus.

Prick-by-prick testing with fresh fig was positive (4 × 5 mm).

Specific IgE was measured for latex, lipid transfer protein, profilin, Bet v 1, fig, and recombinant mite allergens. Results were positive for fig (3.5 kU/L) and Der p 1 (cysteine protease) (4.6 kU/L).

The most frequent adverse reactions associated with fig are phytophotodermatitis and phototoxic reactions. IgE-mediated fig allergy has been associated with several characterized allergens, including Fig c 4 (profilin), fig c, ficin (a cysteine protease), Fig c (a lipid transfer protein), and a 17-kDa protein homologous to Bet v 1. In most reported cases, fig allergy occurs in the context of the latex–fruit syndrome, resulting from cross-sensitization between natural rubber latex (Hevea brasiliensis) and various fruits.

Given that Der p 1 belongs to the same molecular family as ficin, we hypothesize that the clinical reaction observed in our patient may be due to cross-reactivity. Furthermore, due to known cross-reactivity among cysteine proteases, avoidance of kiwi, papaya, pineapple, and mulberry is recommended.

We therefore present a case of fig allergy likely related to cross-reactivity with house dust mites.