Summary

Banana (Musa acuminata/sapientum/paradisiaca) is a perennial herb majorly found in the tropical regions. India, China, Ecuador, Brazil, and the Philippines are the top producers of banana in the world. Banana is a common food in human diet worldwide due to its high nutritional content. However, banana is found to cause allergic reactions in some individuals. The prevalence of banana allergy among general population is considered uncommon, with an estimated to be as low as 0.04% to up to 1.2% globally; however, an increasing trend on the number of cases on hypersensitivity reactions to banana in infants as well as in adults are being reported till date. Ingestion of fresh, uncooked banana fruit is the main cause of allergy as most banana allergens are sensitive to heat. Clinical manifestation of banana allergy ranges from mild local symptoms, referred to as oral allergy syndrome to severe anaphylactic reactions, including asthma and gastrointestinal symptoms in rare cases. The identified banana allergens are profilin - actin binding protein (Mus a 1), class I chitinase (Mus a 2), non-specific lipid transfer protein (Mus a 3), thaumatin-like protein (Mus a 4), beta-1,3-glucanase (Mus a 5) and ascorbate peroxidase (Mus a 6). Extensive cross-reactivity of banana with latex, pollens (olive, birch, palm, ragweed, and hazelnut), and fruits (melons, peach, kiwi, avocado, and pineapple) has been observed.

Epidemiology

Worldwide distribution

Banana is a common food in human diet worldwide due to its high nutritional content. Nonetheless, banana is found to cause allergic reactions in some individuals. The prevalence of banana allergy among general population is considered uncommon, with an estimated to be as low as 0.04% to up to 1.2% globally in different studies. However, increasing number of cases on hypersensitivity reactions to banana in infants as well as in adults are being reported till date. A European Community Respiratory Health Survey analyzed food sensitization (testing up to 24 foods) among 4522 young adults from 13 countries across globe. Sensitization pattern to banana along with walnut, sunflower, poppy, melon, fish, egg, milk, and soy was found to be in the range of 0.2% to 2.5%.

A multicenter, cross-sectional EuroPrevall study conducted to detect the prevalence of self-reported food allergy and food sensitization in 16,935 European school-age children (mean age 8.9 years) found self-reported food allergy prevalence for banana to be 1.1%. A German study evaluating case histories of 380 food-allergic patients (mostly suffering from pollen-related food allergy, PFAS) found 16 patients showing immediate allergic reactions to banana.

In a case-control study on 80 allergic children (40 each with/without history of banana allergy) in Egypt, 7.5% (3/40) were diagnosed with banana allergy based on positive history, elevated serum specific IgE to banana, and positive skin prick test (SPT). The prevalence of banana allergy was higher in this study compared to the general population (0.04%-1.2%), which may due to the inclusion of only atopic individuals in the study.

Further, in a group of 689 allergic patients (15-73 years) from various allergy centers in Pakistan, 7.1% (49/689) patients showed a positive SPT to banana allergen. In a 5-year cross-sectional study testing for food allergy among 5161 patients of all age groups in Kolkata, India, the highest rate of sensitization (32.4%) was observed for banana among all other foods tested.

A cross-sectional retrospective study on 365 American children in Honduras (1 to 18 years) reported 2.2% children sensitive to banana. Further, another study on 160 Columbian children (of age < 2years) with food allergies reported 23% (47/160) to be sensitive to one food based on specific IgE measurement. Banana sensitivity was found in 10% of them.

Risk factors

Banana, rich in vitamins, minerals, and fibers, is often given to infants at a very early age. It has been postulated that infants who are exposed to banana allergens at an early age may be at a risk for the development of banana sensitization. A case study reported an infant to be sensitized to banana. He was probably exposed to the banana allergens via the placenta or breast milk during pregnancy or lactation, respectively or may be even orally by sucking mother’s thumb.

Pediatric issues

Banana is a commonly used food for infants. In Spain and other European countries, non-reported symptomatic cases of banana hypersensitivity among infants is on rise. In accordance to this, a study by Dey et al (2014) with participants of all ages found higher prevalence of banana allergy among children below 15 years of age.

Route Of Exposure

Main

Ingestion of fresh, uncooked banana fruit is the main cause of allergy as most banana allergens are sensitive to heat.

Clinical Relevance

Oral allergy symptoms and Anaphylaxis

Clinical manifestation of banana allergy ranges from mild local symptoms, referred to as oral allergy syndrome (OAS) to severe anaphylactic reactions.

An open-label banana challenge test conducted on 6 adults with a history of banana hypersensitivity depicted systemic symptoms like OAS in all of them with skin manifestation (generalized urticaria) as the most common symptom seen in 83.33% of cases. Other systemic symptoms included hypotension (33.3%), dyspnea, and diarrhea (16.67% each). A severe reaction like anaphylaxis was also observed in all the patients (half of the patients showed grade III anaphylaxis as per Ring and Messmer classification).

In a telephonic survey involving 47 banana allergic children in Turkey, urticaria and gastrointestinal (GI) symptoms were observed in 9% and 6% respectively along with other atopic symptoms while none of the children reported anaphylaxis. In a study by Palacin et al. (2011) on 51 children with severe reactions towards banana, OAS was observed in 53% of patients, and systemic reactions in 47% including urticaria and vomiting, as well as anaphylaxis (n=3).

Anaphylaxis was also observed in 2.8% of 319 Japanese patients with self-reported cases of allergic anaphylaxis due to banana hypersensitivity. Further, individual case reports of anaphylaxis due to banana allergy in infants have been reported. A 4-month-old Hispanic baby with a history of eczema started vomiting with other allergic symptoms like urticaria and cyanosis within 5 minutes of banana consumption. Another 7-month-old boy reported generalized urticaria, vomiting, and respiratory symptoms like wheezing within 2 hours of ingestion of crushed banana. The patient was tested negative to commercial extract of banana but reacted positively in SPT to fresh banana fruit. Moreover, another case of severe angioedema up to the glottis requiring intubation was reported in a 16-month-old girl who underwent an orthotopic liver transplant 8 months ago and was continued tacrolimus immunosuppression since then. As a vitamin source, she used to consume banana daily. Hypersensitivity to banana during tacrolimus medication was thought to be the cause of angioedema in the patient.

Further oral pruritis was observed in 33.3% of 6 adults with a history of banana hypersensitivity during an open-label banana challenge test.

Allergic rhinitis and Asthma

A telephonic survey on 47 banana-allergic Turkish children (age 6.2 ± 2.1 years) reported wheezing, allergic rhinitis (AR), and asthma in 60%, 15%, and 13% of patients respectively. Also, rhinorrhea was reported in 50% of 6 adults with a history of banana hypersensitivity during an open-label banana challenge test.

Atopic Dermatitis

In a Turkish study with 47 banana-allergic children, atopy was found in 87% (41/47) cases while 23% complained of atopic dermatitis.

Other diseases

A 47-year-old woman having a history of AR to Japanese cedar experienced symptoms of acute pancreatitis like nausea, vomiting, and diarrhea after consuming a banana. She had three attacks of acute pancreatitis each time after consuming a banana. She also experienced migraines and pruritis within 2 hours of eating bananas.

Cross-Reactivity

Banana allergy has been correlated with latex and/or pollen suggesting that banana is responsible for latex-fruit, pollen-fruit, and latex-pollen-fruit syndrome.

Latex-food syndrome is observed in about half of the latex allergic patients and linked to various fruits and vegetables including banana, kiwi, avocado, peach, pineapple, chestnut, tomato, potato, and pepper. Individuals developing ‘latex-fruit’ syndrome (commonly seen in health care workers who frequently wear natural rubber latex gloves) are initially sensitized to latex and later become allergic to food due to cross-reacting IgE against allergenic proteins. This latex sensitization results in allergic reactions like urticaria, GI, and in severe cases, anaphylaxis or even loss of consciousness.

Cross-reactivity of banana with pollens of different trees and weeds including palm, birch, plane tree, olive, ragweed, and hazelnut has also been observed. It can lead to the development of banana allergic reactions, such as oral allergy symptoms like itching and swelling of the mouth and throat.

The possible cross-reactive molecules responsible for latex-pollen-fruit syndrome are the gluconases such as Hev b 2 from rubber tree latex (Hevea brasilianis), the Mus a 5 from banana (M. acuminata), and Ole e 9 from olive pollen. These molecules showed high sequence homology and have common IgE epitopes. Besides, cross reactivity also occurs between profilin of banana (Mus xp 1, M. parasiadica), and profilins of rubber tree latex (Hev b 8), olive pollen (Ole e 2), and fruits like kiwi (Act d 9), and ananas (Ana c1). Furthermore, there is an association between ragweed-melon-banana and the probable cross reacting molecules are either profilins or LTPs, such as Mus xp 1 (profilin) of banana, Amb a 6 (LTP), Amb a 8 (profilin) of ragweed (Ambrosia artemisilifolia), Cit la 2 of watermelon (Citrullus lanatus), Cuc m 2 of muskmelon/cantaloupe (Cucumis melo), Cuc p 2 of zucchini (Cucurbita pepo), and Cuc s 2 of cucumber (Cucumis sativus).

Additionally, the cross-reactivity between banana and fruits like peach and pineapple was studied and it was observed that more than 75% of 36 banana allergic patients recognized the major allergen of peach (Pru p 3, nsLTP) on IgE immunoblots in addition to pineapple bromelain (a marker of cross-reactive carbohydrate determinants, CCD).