Allergic rhinitis
Three cases of allergic rhinitis (AR) in adults were reported due to occupational exposure to garlic. All three patients lately developed asthma preceded by AR as an allergic response due to exposure to garlic or garlic powder. The patients were symptomatic when in contact with garlic and remain symptomless without garlic contact (15).
Asthma
Bronchial asthma was reported very early due to occupational exposure of garlic dust. Certain studies have reported scattered cases of asthma as an allergic response to garlic (8, 10). An epidemiological study of 150 spice mill workers for analyzing specific exposure to garlic and chili pepper allergens demonstrated their association with asthma or probable obstructive lung disease. The study reported the prevalence of spice-dust-related asthma-like symptoms in 17% of workers. Sensitization to garlic was seen among 19% of workers and among them, 13% was monosensitized to garlic and 6% cosensitized to chili pepper (16).
Atopic Dermatitis
Pandhi et al. (2020) evaluated 100 Indian hand eczema patients for clinical subtype and pattern of contact sensitization to various allergens causing hand eczema. Exposure to garlic was found to be the etiological reason in 9% of patients with allergic contact dermatitis to be the most common clinical pattern of hand eczema (17).
Other diseases
Allergic contact dermatitis is considered to be the most common allergic reaction with garlic. A study evaluating 1092 patients for patch tests to diallyl disulfide revealed 19 patients with a positive test with hands as the most frequently affected site. This study revealed sensitivity to diallyl disulfide to be more common in females than males (5). The study to screen food allergy on 108 Saudi patients showed several allergic symptoms in sensitized individuals like urticaria in 5, gastrointestinal symptoms in 5, contact dermatitis in 3 and asthma in 2 patients. (10). Another study on 8109 Spanish patients presented hypersensitivity reactions to 44 aeroallergens and food allergens including garlic and onion. The hypersensitive symptoms to garlic majorly included chronic diarrhea and dyspepsia along with asthma and pulpitis in index fingers and thumb of left hand (8).
Anaphylaxis after oral intake of garlic is extremely rare (9), Treudler, Reuter (18) There was a reported case of anaphylaxis in an allergic 48-year old man (with seasonal AR and gastroesophageal reflux) after ingestion of raw garlic. He had a history of generalized urticaria, angioedema and vomiting after ingestion of garlic sauce and also urticaria, angioedema and hypotension after ingestion of tzatziki (yoghurt, garlic, olive oil, vinegar, cucumber and pepper). IgE binding assay identified alliinase as the major causative allergen in addition to 8 other proteins which may be responsible for an allergenic response (18). An unusual case of anaphylaxis in a 16-month old male infant is also reported and is attributed to the consumption of garlic flavored yogurt. The patient presented with diffuse erythema, itching, swelling of the eyelids and lip, vomiting, cough, and wheezing and was diagnosed as anaphylaxis. The sensitization of infants may be through breast milk or during pregnancy as the mother testified to consume garlic containing food during pregnancy.(9).
Other topics
The array of garlic induced skin reactions are varied in different patients. Few studies reported irritant contact dermatitis on exposure to garlic (19, 20). Pemphigus was also reported attributing to garlic as a dietary factor (21).
