Introduction
Amorphophallus paeoniifolius (Dennst.) Nicolson (Araceae) called as elephant foot yam has originally come from Southeast Asia. It is considered to be a staple food in India, Indonesia, Philippine, Bangladesh, China and some other Southeast Asian countries. In India, it is commonly called as ‘jimmikand’ or ‘suweg’. It grows quite well in aerated coarse textured soils with adequate rainfall. It is known to have numerous medicinal properties and thus so possesses potentials of an herbal drug. It is used in many ayurvedic preparations to treat several ailments like tumors, cough, elephantiasis, haemorrhage, seminal weakness, amenorrhea, asthma fatigue and anemia.1 It acts as a potent agent in gastrointestinal abnormalities like vomiting, constipation, hemorrhoids etc.1, 2 Suweg contains high percentages of flavonoids and alkaloids which accounts for its antimicrobial activity along with its antifungal and antihelminthic effects.3 Yuzammi et al calculated the nutrient percentages in suweg of Java. It was found to have highest carbohydrates and proteins content with lowest fat concentration. Phosphorus and calcium were the minerals found in largest quantity.4 Even though after the introduction of rice and cereals, use of suweg became unpopular, it is still considered as a sub dietary food in many countries. Since it is a common food, it is usually cooked by steaming or boiling and is rarely consumed in its raw form.
Allergic reactions to elephant foot yam are very rare in both clinics and literature especially when consumed in a cooked form. Even though Amorphophallus paeoniifolius has enormous ethno-medicinal use in several ailments and pharmacological findings, still oral toxicities been reported in patients when they consumed it in a raw form. However, allergic reactions due to cooked elephant foot yam have not been published much. Here, we will discuss a case study of a female who showed allergic reactions on her skin externally after she ate cooked elephant foot yam.
Case Study
A 16 years old Asian female with body weight 40 kg, height 5 feet, 3 inch started experiencing rashes, wheals-flares on upper and lower extremitiesin the evening 4:00 PM after consuming cooked yam (jimmikand) at 12:00 PM.
The rashes gradually progressed to arm and trunk region by 6:00 PM. On Examination, Blood pressure, pulse rate was normal. Anti-histaminic treatments were given at the local OPD. The event subsided thereafter. The next day at 12:00 PM, again the rashes reappeared with itching and redness over upper and lower extremities. By 9:00 PM, at night, the rashes spread to her face with sensation of burning and pruritus. Patient was rushed to hospital, where she was given Inj. Hydrocortisone 100 mg STAT, Inj. Chlorpheniramine maleate 10 mg/ml. Emergency discharge treatment included Tab Levocitrizine 5 mg once a day at bed time for 2 days.
Discussion
Elephant foot yam has been well known for its acrid taste and possible injurious potentials when consumed in a raw form. Previously, it was determined that the reason for such reactions is the presence of calcium oxalate crystals on its surface. Koni et al. confirmed through his studies that calcium oxalate which is insoluble in nature was produced after a chemical reaction of oxalate and calcium thereby decreasing calcium absorption.5
The major cause of acridity in elephant foot yam has been associated with calcium oxalate.5 Consumption of higher quantities of calcium oxalate might affect people with allergies and may even cause death if 50mg in concentration.6 However, it was stated that calcium oxalate could be removed by several treatments like dicing, soaking in saline water, drying and cooking.7
Calcium oxalate crystals can be divided into five categories (crystal sand, raphides, druse, styloid, prismatic) based on their shape and morphology.8 They are considered good for calcium regulation, plant protection, tissue support and detoxification of heavy metals. Upon tissue contact it gets penetrated causing ejector cells to release a protein called protease which further leads to tissue swelling and damage.9
Injuries on exposure to calcium oxalate crystals of elephant foot yam have been reported in the past. V. Ceretto in 2018 wrote a case study in which a 55 year old Asian female developed oral pain, swelling and numbness after consuming stir fried elephant root. This was a case of acute oral toxicity.10 In one report, around 200 people exposed to Araceae developed toxic symptoms but were all very mild.11 Mostly allergies related to oral mucosa were reported majorly followed by pruritus, erythema, and wheal on external skin and hands.
In our study, the female experiences type- II delayed hypersensitivity reactions and the possible reason for the development of these allergic reactions in the female can be the presence of calcium oxalate crystals. Since, nothing abnormal was observed in her diagnostic reports; the possible reason for the anaphylaxis can be based on previous findings. Pharmaceutical treatments with little evidence of efficacy that can currently be used are corticosteroids and most importantly anti-histaminergic drugs. Therefore the female was given anti histaminic treatment of levocitrizine and doses of hydrocortisone and chlorpheniramine maleate.