Mango allergy in a latex-sensitized patient

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A llergy to such different fruits and nuts as banana, chestnut, kiwi, or avocado has frequently been described. However, only a few cases of mango allergy have been reported ( 1–4). Like other food allergens, that of the mango can produce oropharyngeal syndrome, urticaria, and sometimes anaphylaxis ( 1–3), possibly causing life-threatening complications. Contact dermatitis of the face and lips ( 4) and asthma ( 5) after mango consumption have also been described.

On the other hand, allergy to tropical fruits has been identified in many latex-sensitized patients in whomcross-reactivity between latex and fruits – the so-called latex-fruit syndrome – has been shown ( 5). We report a case of mango allergy in a latex-sensitized patient. A 45-year-old nurse had been diagnosed as having latex sensitization 3 years before. Her clinical manifestations when in contact with latex included rhinoconjunctivitis, bronchial asthma, and contact urticaria. She usually avoided contact with latex. The patient had occasionally eaten mango for 2 years, without problems. After eating one fresh mango, she immediately suffered oral allergy syndrome, rhinoconjunctivitis, cough, and dyspnea requiring treatment with antihistamines, inhaled β2-agonists, and corticosteroids. Skin prick-prick tests with fresh mango were positive (2+) in the patient but negative in three healthy controls. Class 3 mango-specific IgE levels (RAST) were moderately increased (10.4 kU/l). An immunoblot inhibition assay was performed to investigate possible cross-reactivity between mango and latex ( Fig. 1). The results showed IgE binding to mango proteins of 25–50 kDa in the patient serum, as well as IgE binding to latex proteins of 40 kDa. Cross-reactivity between mango and latex was not shown.

Figure 1.

Comparison of major cross-reacting T-cell epitope of plant pollen proteins Bet v IX (Betula verrucosa), Poa p IX (Poa pratense), Lol p I (Lolium perenne), and Phl p I (Phleum pratense) with homologous sequences retrieved from SwissProt and Pir databases (releases 2/1999). Boxed letters indicate conserved amino-acid residues according to motif suggested by Mohapatra et al. ( 3).

Only a few cases of mango allergy have been reported, to our knowledge. However, the real frequency may be underestimated because of low consumption of this fruit in the northern hemisphere. The mango plant contains several substances thought to be sensitizers such as cardol, uroshiol, β-pinene, and limonene ( 1). The hypersensitivity mechanism leading to anaphylactic reactions is probably mediated by IgE, as shown by the skin test positivity and IgE RAST detection. Other possible mechanisms of less severe reactions, such as contact urticaria, would be mediated by antibodies of IgG4 type ( 1).

Latex allergy is common among certain professionals at increased risk such as health-care workers. Many latex-sensitized patients show the latex-fruit syndrome, which consists of oropharyngeal syndrome and sometimes anaphylaxis ( 5). Cross-reactivity between latex and some fruits and nuts – banana, chestnut, kiwi, or avocado – has been described ( 5). Biologic cross-reactivity between latex and mango has also been reported ( 5). Cross-reactivity is believed to be due to a common epitope shared by both latex and fruits. Several plant proteins such as profilins, endo-1,3-β-glucosidases, and patatin have been suggested, although the responsible proteins have not yet been identified ( 5). We could not show cross-reactivity between latex and mango in our patient, so we made the diagnosis of independent mango allergy in a latex-sensitized patient. Therefore, it is important to bear in mind that not every case of fruit allergy in a latex-sensitized patient can be diagnosed as latex-fruit syndrome if the proper biologic tests have not beenperformed.

Footnotes

  1. An IgE-mediated reaction of rhinoconjunctivitis and dyspnea.

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