Severe allergic reactions and Anaphylaxis
Cashew nuts allergy are generally associated with severe reactions, i.e. initially manifested as skin reactions, which are followed by respiratory, gastrointestinal, and even systemic allergic reactions, such as anaphylaxis (1).
In a study conducted in The Netherlands among 137 suspected cashew-allergic children, positive to DBPCFC test, the majority of them reported gastrointestinal symptoms (72%), followed by oral allergy (64%), skin (urticaria: 21%, angioedema: 27%) and respiratory symptoms (upper airway: 15%, lower airway: 7%) (15). In a study conducted in Sweden among 46 cashew-allergic patients confirmed by DBPCFC, allergic reactions such as skin, gastrointestinal and respiratory reactions were reported in 91%, 61% and 11% of patients, respectively (29).
A retrospective analysis conducted on 52 cashew nut-allergic patients in Singapore reported severe allergic reactions, with cutaneous being the most prominent (71.2%), followed by gastrointestinal and respiratory reactions in 44.2% and 30.8%, respectively. Anaphylaxis was also reported in 3.8% of patients (30). Furthermore, in a study conducted in Japan, the challenge-positive cashew-allergic children (n=12) reported gastrointestinal symptoms as the most common allergic symptoms (91.7%), followed by skin (58.3%), respiratory (50%), neurological (25%) and cardiovascular symptoms (8.3%). In this study, anaphylaxis was also reported in 41.7% of children (17).
A study conducted in Australia among 90 children with positive cashew-OFC, reported angioedema in 61.1%, skin reactions in 60%, oropharyngeal symptoms in 48.9%, respiratory reactions in 13.3% and gastrointestinal symptoms in 35.6% of children (19).
In the European Anaphylaxis Registry that compiled data of 1970 patients (<18 years) between the year from 2007 to 2015, cashew nut was found to be an elicitor in 7.1% (78 out of 1092) of patients with anaphylaxis due to food. Furthermore, based on age group, cashew was found as an important elicitor of anaphylaxis in pre-school children (<6 years) (58 out of 78; 74.3%) when compared to other age groups (6 to 12 years: 21.7% and 13 to 17 years: 3.8% ) (31). Similarly, a retrospective study reported cashew to be responsible for 44% of tree-nut-induced anaphylaxis in preschool children (11 out of 25) (32).
Allergic rhinitis
In a prospective cohort study involving 112 children with a history of pistachio and/or cashew nut allergy, AR was reported in 13.3% of children with a history of cashew allergy (4 out of 30) (27). Furthermore, in a retrospective study conducted on 55 cashew nut-allergic Irish patients, AR was reported in 65% of patients (28), whereas it was reported to be 42.2% in 64 cashew-sensitized patients in another retrospective study conducted in Taiwan (14).
Asthma
In a study conducted in the Netherlands, asthma was reported to be 31% in cashew nut-sensitized children (55 out of 179) (15). In two studies conducted in France among 52 and 51 cashew nut-allergic children, asthma was reported in 44.2% and 41.2% of children, respectively (33, 34). Furthermore, in a retrospective study conducted in Ireland among 55 cashew nut-allergic patients, asthma was reported in 44% of patients (28), while it was reported to be 12.5% in 64 cashew-sensitized cases, in another retrospective study conducted in Taiwan (14).
In a study conducted in Japan among 66 cashew-sensitized children, 45.5% of patients were reported having bronchial asthma (17). Furthermore, asthma was reported in 46.7 % of children with a history of cashew allergy (14 out of 30) in a prospective study conducted in Turkey (27).
Atopic Dermatitis
In a study conducted in the Netherlands, AD was reported to be 39% in cashew nut-sensitized children (70 out of 179) (15). Two studies conducted in France showed AD in 73.1% (n=52) and 60.8% (n=51) of cashew nut-allergic children (33, 34).
In a study conducted in Ireland among 55 cashew nut-allergic patients, AD was found in 76% of patients (28). Furthermore, in a prospective study conducted in Turkey, AD was reported in 56.3% of children with a history of cashew allergy (9 out of 16) (27). In another study conducted in Japan among 66 cashew-sensitized children, 75.8% of children reported AD (17).
Furthermore, contact dermatitis has been observed in cashew-nut workers who may have been sensitized to cardol present in cashew nut shell liquid. It has been reported that these workers might have come in contact with the nut shells before heating and would have developed irritant reactions (35). This was further observed in 294 patients with contact dermatitis, where a positive reaction to cardol patch test was observed in 8.3% of patients in Brazil (36).
Rhino-conjunctivitis
In two studies conducted in France among 52 and 51 cashew nut-allergic children, rhino-conjunctivitis was reported in 32.7% and 33.3% of children, respectively (33, 34). While in a study conducted in Japan among 66 cashew-sensitized children, 22.5% of children reported allergic conjunctivitis (17).