Potato sensitisation in children: clinical characteristics and demographic profile

Introduction

Food allergy is a growing public health problem worldwide and is the second most common allergic condition after asthma [1]. In Europe, white potatoes (Solanum tuberosum) are widely consumed, and around the age of 5 to 6 months, they are frequently added to children’s diets in their cooked form [2]. Despite its widespread consumption, allergic reactions to potato are rarely reported [3]. Potato sensitisation may result in a broad spectrum of IgE-mediated allergic reactions, including contact urticaria, anaphylaxis, protein contact dermatitis, or oral allergy syndrome. Additionally, non-IgE-mediated responses such as food protein-induced enterocolitis syndrome (FPIES) have also been described [4, 5]. In certain populations, particularly within Mediterranean countries, potato sensitisation may affect as many as 10% of allergic individuals [6]. However, most studies in the literature are limited to case reports, and comprehensive data – especially in children – remain scarce [1].

Aim

In this study, we evaluated the clinical and demographic characteristics of our patients with potato sensitisation.

Material and methods

This retrospective study was conducted between January 2022 and January 2023. All patients diagnosed with potato sensitisation during this period were included. Because this was an observational study based on existing patient records, no formal sample size calculation was performed. These patients’ skin prick tests revealed sensitisation to the raw or cooked potato allergen. Cases were defined as cooked potato-induced allergic reaction if the provocation test with cooked potato was positive (1), if symptoms improved with elimination of potato from the diet and symptoms were observed again with reintroduction of potato into the diet (2), and if clinically definite symptoms were noted after eating cooked potato (3).

In patients without a history of immediate reaction to potato, home reintroduction of potato was recommended following a 15-day potato-containing diet. During the elimination period, no other treatment was initiated in patients with eczema, and no concurrent diet with another food was recommended. Demographic characteristics of the patients such as gender and age were recorded. Total IgE and eosinophil values were evaluated. Allergic diseases of other family members were questioned. Allergic rhinitis was diagnosed according to Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines [7]. In addition, atopic dermatitis was diagnosed according to Hanifin and Rajka diagnostic criteria [8]. World Allergy Organisation Anaphylaxis Guidance 2020 criteria were used for the diagnosis of anaphylaxis [9].

Results

A total of 247 patients were evaluated, of whom 25 had potato sensitisation. A total of 247 patients with eczema findings or reaction history to raw or cooked potatoes underwent a potato prick-to-prick test. Most of the patients were male (136 [55.06%]). The average age at presentation was 18.5 ±10.8 months. The frequency of potato sensitisation in this group was 10.1% (25/247). In 3 cases, a reaction with raw potato was observed (after contact), whereas a reaction with cooked potato was observed in the other cases. When sensitisation to raw and cooked potato was evaluated, and no significant correlation was found between pollen allergy and sensitisation to raw or cooked potato (p > 0.05). Eczema was the leading presenting symptom in 12 (48%) patients. Urticaria was present in 8 cases, and it occurred in 3 cases as contact urticaria due to contact with raw potato, they consumed cooked potatoes. Recurrent reactions after potato consumption were present in 4 patients with a history of urticaria. Cases of urticaria were observed between 0.5 and 1 h after potato consumption. All cases of urticaria were in the form of acute urticaria. In 1 case, the diagnosis of anaphylaxis was made according to the patient’s medical records and anamnesis findings. The case of anaphylaxis was a 9-month-old girl with urticarial rash and symptoms of runny nose and sneezing 0.5 h after eating cooked potatoes. The diagnosis of anaphylaxis was based on clinical history, and the clinical history was consistent with anaphylaxis. In 1 case, oral allergy syndrome developed after ingestion of potatoes (Table 1).

Allergic rhinitis was found in 7 patients, asthma in 6 patients, and eczema in 12 patients. Five of the patients with sensitisation had a family history of atopic disease.

Potatoes were eliminated from the diet in 8 patients with eczema, and potatoes were added to the diet again at home. Five patients showed improvement in eczema with diet and exacerbation of eczema with reintroduction of potato in the diet. Three patients with eczema that did not improve with diet were evaluated as sensitisation. In 4 patients with eczema, elimination diet was not administered because of lack of family compliance.

Nineteen (76%) patients were sensitised with other allergens. Sensitisation to egg white, milk, hazelnut, lentil, and egg yolk was detected in 16, 8, 6, 4, and 2 patients, respectively. The most common aeroallergen was grass pollen. Sensitisation to respiratory allergens was found mostly to grass pollen.

When eosinophil and total IgE values were compared between the groups with and without potato sensitisation, no significant difference was found between eosinophil (p > 0.05) and IgE (p > 0.05) values.

Discussion

Our study is one of the rare studies evaluating potato sensitivity. Although potato allergy is unusual, it was found to be the most common cause in a study evaluating vegetable and fruit allergies [10]. Similar to the study by Doğru et al., the number of male patients was high in our study [1]. However, in a large population study, potato sensitivity was found to be higher in females [6].

In the study by Doğru et al. the most common clinical feature was atopic dermatitis [1]. In 2 separate studies by De Swert et al. all patients had atopic dermatitis [2, 11]. Also, in another study that examined positive skin and oral challenge responses to potato, as well as the presence of immunoglobulin E antibodies to patatin (Sol t 1) in infants, all of the patients had atopic dermatitis [5]. In our study the most common clinical condition was atopic dermatitis, similar to the literature. Foods do not usually cause respiratory symptoms. Respiratory symptoms were reported as the 2nd symptom in the study by Doğru et al. [1]. Monti et al. described 2 housewives in whom raw potatoes caused respiratory symptoms [4]. De Swert et al. found wheezing and rhinitis in 40% of patients with potato allergy. None of our patients had respiratory symptoms with potato.

Potato sensitisation can present in different clinical forms, as illustrated by a case of contact urticaria after contact with raw potatoes reported by de Lagrán et al. [12]. Monti et al. also reported an acute food protein-induced enterocolitis syndrome (FPIES) [4], while urticaria and angioedema were the second most common clinical symptoms in our study.

The most common cause of anaphylaxis in childhood is food [13]. Potato anaphylaxis reported in the literature is rare. In the study by Doğru et al. anaphylaxis was observed in 4 (10%) cases [1]. De Swert et al. evaluated 36 patients and found 3 cases of anaphylaxis [2]. There was also 1 case report of a severe reaction to both raw and cooked potatoes [14]. Kobayashi et al. described a case of anaphylaxis after playing with potato clay in a child with eczema [3]. In our study, anaphylaxis was seen in only 1 patient.

In the study by Doğru et al. the most common food sensitivity accompanying potato sensitivity was egg white sensitivity [1]. De Swert et al. found that egg and milk sensitisation was the most common concomitant sensitisation [2]. Grass pollen allergy was found in 5 cases in a study conducted in our country [1]. De Swert et al. reported grass pollen allergy in 9 cases [2]. In our study, the most common food allergy was egg white, and grass pollen sensitisation was demonstrated in 5 patients.

Three patients had a history of reaction with raw potato, and the reaction seen in 3 patients was urticaria. Doğru et al. suggested that variability in patient reactions to raw potato may be explained by differences in the specific allergens responsible for potato sensitisation [1]. Although it cannot be fully explained, the major potato allergen, patatin (Sol t1), may be the reason for the differences between the cases.

The gold standard method for the diagnosis of food allergy is still the double-blind placebo-controlled food challenge test [15]. However, we could not perform a food challenge test on all our patients, so we used the term potato sensitisation instead of potato allergy. There is also a study showing a high specificity in tests for suspected potato allergy [2].

Since our study was retrospective, it has some limitations. First of all, we used the term potato sensitisation instead of potato allergy because provocation was not performed in all patients. In addition, potato-specific IgE could not be tested. Skin reactivity to apple, carrot, and potato was examined in the context of clinical associations with birch pollen allergy [16]. But in our study, patients were not evaluated in terms of birch pollen.

Conclusions

Potato sensitisation is most common in children with atopic dermatitis. Potato allergy should be considered in patients who do not improve despite topical treatments and elimination of foods that cause more frequent atopic dermatitis such as milk and eggs from the diet.