Cacao (Theobroma cacao) is a small tree belonging to the Malvaceae family. Its seeds are used to make cocoa powder and chocolate which is consumed around the world. Cacao allergy can induce cutaneous, oral/gastrointestinal, respiratory symptoms, , and anaphylaxis after ingestion. Studies have shown that individuals working with cacao seeds are at risk of experiencing allergic reactions due to their allergen's inhalation. To date, no major cacao allergens have yet been recognized. The seed of this plant contains albumin 2S protein, which is associated with allergenicity. Cross-reactivity has been observed with chocolate, lupin, milk peanut, walnut, tree nut etc.

Worldwide distribution

A survey was done in Central America in El Salvador to estimate the prevalence of parent-reported food allergy in school children. The study stated 4.3% of the reported food-related adverse reactions, and 0.78% said food allergen associated allergic reactions were commonly due to chocolate(5). A study was conducted in Russia, Estonia, Lithuania, Sweden, and Denmark to know the prevalence of self-reported hypersensitivity reactions to different foods. A total of 1139 patients were included. The result showed that 32% of patients had a chocolate allergy, whereas 15% had cocoa (cacao) allergy. In the eastern countries, food eliciting severe symptoms other than chocolate was found to be strawberry, hazelnut, milk, peanut and walnut while in western countries they were hazelnut, walnut, peanut, brazil nut, pistachio nut and milk. (6). A study was conducted in Turkey to know the prevalence of food-related adverse reactions in 6 to 9 years old (n=3500) children. The study showed that around 31.6% percent of the children were allergic to cocoa (cacao) among parental-reported allergies. Additionally, reports confirmed through skin prick tests, and food challenge tests showed around 14.7% and 18.1 %, respectively, were allergic to cocoa (cacao) (7).

Risk factors

In a study done on 71 confectionery workers, the results showed 31% of the workers had a positive reaction to skin test using cacao extract. The prevalence of asthma was 26.1% and dyspnoea 26.1% percent among these workers, which was considerably higher than other workers. (8).

Pediatric issues

A food allergy study was conducted in Finland on 866 children aged 1 to 6 years. The children selected in the study suffered from a skin rash or heavy vomiting after food intake. Among these 802 children with recent history information showed chocolate allergy through antigens against chocolate in 2% in children aged one year, 4% in children aged 2 and 3 years and 1% in children aged six years (9). A study in Turkey showed that in children, most reported allergies was to chocolate. Among these, cocoa was a common causing sensitization and the second most common food with milk (from cow) to cause IgE-mediated food allergic reactions. (7)

Worldwide distribution

Cacao is a tree originally from the northern and humid areas of the United States' north and central parts (1). The cacao plant is a tropical plant with its origin most probably from South America. After the 15th century, its cultivation has been extended to the regions such as Venezuela, Ecuador, Trinidad, and other areas of America. Currently, the western parts of Africa and Asia produce the world's highest cacao (10).

Main

Cacao allergy occurs mainly through the ingestion route (11).

Secondary

Also, the inhalation of cacao has been found to trigger asthma (11).

Food can cause a reaction such as cutaneous, oral/gastrointestinal, respiratory symptoms, and generalized reactions, including fatal anaphylaxis (7)

Anaphylaxis

In a university in Spain, a study was conducted to analyze the intake of cocoa and students' health status. The results were grouped according to low (LC), moderate (MC), and high (HC) consumers of cocoa. Among 270 participants, 87 were cocoa intolerant. Among the groups, 28%, 13% and 19% were allergic to the LC, MC and HC group, respectively. Around 36% of these showed cutaneous reactions such as hives, redness or itching. Approximately 34% of the individuals developed symptoms like rhinitis, sneezing or mouth itching. Among these allergic patients, three of them, due to severe reaction, had to stay home for recovery(12).

Contact Urticaria

A study to investigate allergens causing acute urticaria in children was conducted in Iran. One hundred and twenty-nine children suffering from acute urticaria participated in the study. Among these, 11.6% were observed to show positive skin prick tests to cocoa. Studies have shown in some cases, following food avoidance treatment to children suffering from urticaria may cause malnutrition, developmental and behavioral disorders (13). 

Gastrointestinal

A study in Mexico analyzing patients with food allergy reported 23% suffering from gastrointestinal symptoms, 38% with cutaneous rash, 15% with eczema and 17% with wheezing or cough. Among these patients, 8.3% were observed to have sensitization towards cocoa, 28% to milk, 6.6% to almonds and 5% to peanuts (14, 15).

Atopic Dermatitis

A study was done in Finland to know the prevalence of allergic reactions in 1120 atopic individuals with common spices using a scratch test. In these patients, atopic dermatitis was detected in about 50% of the patients. Around 2.2% showed positive skin tests to cocoa (16).

Allergic Rhinitis (AR) and Allergic Rhino Conjunctivitis (ARC)

A study was conducted in Turkey to know the prevalence of anamnestic food allergy in patients with seasonal allergic rhinitis. The results showed that around 1.2 percent of the patients (n =9) had an allergic reaction to cacao (17). 

Asthma

A case was reported from Canada in which occupational asthma occurred due to cacao. A confectionary worker, aged 31 years, had a history of allergy (familial and personal). The worker developed symptoms such as nasal pruritus and congestion, rhinorrhoea, sneezing, shortness of breath, coughing and wheezing after coming in contact with cacao beans. The study stated these symptoms seemed to improve after removing his connection with the cacao beans during his work (11).  In another study in confectionery workers, the prevalence of asthma was 26.1% percent in workers with positive skin prick tests. These positive results occurred with cacao, chocolate and cocoa extracts to 31%, 9%, and 6% of the workers, respectively (8).

Prevention strategies

Avoidance

The primary strategy to avoid cacao allergy is to completely abstain from such foods (4,7).

Allergenic molecules

No major cacao allergens have been identified (4). A cacao seed protein 2S albumin has been determined, which is recognized to be in storage polypeptide is responsible for allergenicity (4). A particular gene produces a 67-kDa storage protein precursor of cacao. SDS–PAGE analysis has identified the presence of influential bands at 30and 44 kDa. These bands get damaged in the processes such as germination and fermentation. Another major cacao seed protein with a band of 21 kDa has also been identified (18).

Biomarkers of severity

The cacao seed albumin 2S is associated with allergenicity (4).

Cross-reactivity

Cross-reactivity has been found with patient serum consisting of chocolate and lupin extract (19). A minor allergen from walnut (vicilin family) shows about 90 percent similarity with cocoa (cacao) vicilin (20). Cacao has also been known to be cross-reactive with peanut, milk, tree nuts, and tobacco and ragweed. This cross-reactivity is mostly due to similar polyphenols haptens in these substances (4, 21).

Author: Turacoz Healthcare Solutions

Reviewer: Dr. Christian Fischer

Last reviewed: November 2020