Food contact hypersensitivity syndrome: the mucosal contact urticaria paradigm

Differential Diagnosis of Urticarial Lesions

Urticaria is a mast cell-dependent disease, characterized by the presence of wheals, angioedema, or both in the absence of systemic symptoms. It is a common disease worldwide, with an important health burden especially in chronic situations, that last more than 6 weeks. Although urticaria is usually a straightforward diagnosis, some diseases presenting with urticarial lesions must be excluded, particularly urticarial vasculitis and auto-inflammatory syndromes. In these settings additional atypical features are often present (long-lasting lesions, bruising, fever, malaise, arthralgia), allowing the clinician to suspect a diagnosis other than urticaria. The authors propose an approach based on these atypical features, the presence or absence of systemic symptoms and on skin histopathology as well as some blood parameters.

Adult-onset IgE-mediated food allergy at a Winnipeg allergy clinic: a case series

BACKGROUND

It is a putatively understood phenomenon that the overall prevalence of allergic disease has been increasing in recent decades-particularly in industrialized nations. Despite this, there is a relative scarcity of data concerning the development of food-related allergic disease in the adult population. In addition, the paucity of data as it pertains to the Canadian population is particularly marked when compared to other nations. We sought to determine common culprit foods and the reactions they elicited in a series of 14 patients seen in the Winnipeg allergy and immunology clinic.

METHODS

We conducted a retrospective review of patients identified by academic allergists in Winnipeg, Manitoba as fitting criteria for adult-onset IgE-mediated food allergy from May 2018-July 2020. We included patients with IgE-mediated symptoms, including the pollen-food syndrome which developed at the age of 16 or later. We collected data regarding the food which induced the reaction, what the reaction was, and any concomitant atopic disease.

RESULTS

The most common culprit food identified was shellfish, followed by finfish, pollen-food syndrome, and wheat/flour. The most common reaction experienced was anaphylaxis, followed by food-dependent exercise-induced anaphylaxis and isolated (muco)cutaneous symptoms. With regard to concomitant atopic disease, allergic rhinitis/rhinoconjunctivitis stood out as the most prevalent.

CONCLUSIONS

Adult-onset food allergy-particularly with resultant anaphylaxis-is an important phenomenon to recognize, even when patients have previously tolerated the food in question.

Pollen food allergy syndrome (PFAS): A review of current available literature

OBJECTIVE

Pollen food allergy syndrome (PFAS) is a complex syndrome posing a diagnostic and therapeutic challenge. Our objective was to summarize the available literature regarding its prevalence, pathogenesis, diagnosis, and treatment.

DATA SOURCES

A PubMed search was performed to include English language articles with the following search terms: pollen food syndrome, pollen food allergy syndrome, PFAS, oral allergy syndrome, OAS, food anaphylaxis, food components.

STUDY SELECTIONS

Human articles discussing PFAS.

RESULTS

Varying reports have been made of the prevalence of PFAS, ranging from 4.7% to greater than 20% in children and 13% to 58% in adults. Prevalence varies widely by geographic region. PFAS is typically the results of class II food allergens (e.g. sensitized to anaeroallergen, but reaction occurs due to cross reactivity from a food allergen). Commonly these reactions are limited to the oropharynx due to the lability of the proteins causing the reaction. As multiple families of proteins with varying stability cause PFAS, severe systemic reactions are also possible, as anaphylactic shock has been documented in up to 1.7% of reactions.

CONCLUSION

Pollen food allergy syndrome therefore cannot be dismissed as a benign food allergy, but it needs to be approached individually based on known risk factors.

Triggers of oral lichen planus flares and the potential role of trigger avoidance in disease management

OBJECTIVE

Many patients with oral lichen planus (OLP) report triggers of flares, some of which overlap with triggers of other oral diseases, including oral allergy syndrome and oral contact dermatitis. The purpose of this study was to evaluate the prevalence of commonly reported triggers of OLP flares, their overlap with triggers of other oral diseases, and the potential role of trigger avoidance as a management strategy.

STUDY DESIGN

Questionnaire-based survey of 51 patients with biopsy-proven lichen planus with oral involvement seen in an academic dermatology specialty clinic and/or oral pathology clinic between June 2014 and June 2015.

RESULTS

Of the participants, 94% identified at least one trigger of their OLP flares. Approximately half of the participants (51%) reported at least one trigger that overlapped with known triggers of oral allergy syndrome, and 63% identified at least one trigger that overlapped with known triggers of oral contact dermatitis. Emotional stress was the most commonly reported trigger (77%). Regarding avoidance, 79% of the study participants reported avoiding their known triggers in daily life. Of those who actively avoided triggers, 89% reported an improvement in symptoms and 70% reported a decrease in the frequency of flares.

CONCLUSIONS

Trigger identification and avoidance can play a potentially effective role in the management of OLP.

Cross-React: a new structural bioinformatics method for predicting allergen cross-reactivity

The phenomenon of cross-reactivity between allergenic proteins plays an important role to understand how the immune system recognizes different antigen proteins. Allergen proteins are known to cross-react if their sequence comparison shows a high sequence identity which also implies that the proteins have a similar 3D fold. In such cases, linear sequence alignment methods are frequently used to predict cross-reactivity between allergenic proteins. However, the prediction of cross-reactivity between distantly related allergens continues to be a challenging task. To overcome this problem, we developed a new structure-based computational method, Cross-React, to predict cross-reactivity between allergenic proteins available in the Structural Database of Allergens (SDAP). Our method is based on the hypothesis that we can find surface patches on 3D structures of potential allergens with amino acid compositions similar to an epitope in a known allergen. We applied the Cross-React method to a diverse set of seven allergens, and successfully identified several cross-reactive allergens with high to moderate sequence identity which have also been experimentally shown to cross-react. Based on these findings, we suggest that Cross-React can be used as a predictive tool to assess protein allergenicity and cross-reactivity.

Availability and Implementation

: Cross-React is available at: http://curie.utmb.edu/Cross-React.html.

Contact

ssnegi@utmb.edu.

Food allergen-mediated exacerbations of oral lichen planus

Erosive oral lichen planus (OLP) is a chronic autoimmune condition of unknown aetiology, characterized by periods of exacerbation and quiescence. Many patients with OLP report triggers of flares that overlap with triggers of other oral diseases, including oral allergy syndrome (OAS), an IgE-mediated food allergy. We report a case that, to our knowledge, is the first reported case of concurrent OLP and OAS diagnoses, which provides insight into the triggers of OLP and the role of trigger avoidance. A woman in her 60s presented with erosive OLP refractory to prednisone and azathioprine. She reported that certain food exposures triggered flares of her OLP. She was subsequently diagnosed with concurrent OAS, and avoidance of food allergens resulted in a clinically significant improvement in her OLP, eventually allowing her to taper off systemic treatment altogether. Further studies are needed to pinpoint common triggers and examine the role of trigger avoidance as a management strategy for OLP.

The prevalence of the oral allergy syndrome and pollen-food syndrome in an atopic paediatric population in south-west Sydney

AIM

Oral allergy syndrome (OAS) and pollen-food syndrome (PFS) are regarded as uncommon manifestations of paediatric atopic disease. However, little Australian data exist. The aim of this study was to examine the prevalence of OAS in an atopic, paediatric population.

METHODS

This cross-sectional study assessed 163 patients aged 4-17 years from the Paediatric Allergy & Immunology Clinic at Campbelltown Hospital, which serves a population base >250,000 with approximately 28% under the age of 18 years. A questionnaire was administered and skin prick tests (SPTs) were performed utilising commercial extracts and fresh and frozen fruit samples. Frozen samples were created by reducing fresh fruit to a semi-solid state and storing at -20 degrees Celsius for up to 6 months.

RESULTS

Within the studied population, the prevalence of OAS was 14.7%, PFS 4.9%, PFS in those with allergic rhinitis 6.25% and PFS in those with allergic rhinitis and pollen sensitisation 12.1%. All PFS-implicated fruits were tropical fruits with watermelon the most common. The prevalence of OAS caused by food allergy was 13.6%, implicating peanut most frequently. The most common cause of OAS was immunoglobulin E-mediated food allergy (57.9%). Only frozen samples of watermelon, pineapple and rockmelon produced results consistent with the 'gold standard' of fresh fruit SPT.

CONCLUSION

This study suggests the prevalence of OAS and PFS are more common in paediatric populations than previously described, with tropical fruits predominantly implicated in PFS. Further research is required to determine whether frozen fruits are a reliable alternative to fresh fruit in SPT.

Contact urticaria syndrome caused by haptens

In the group of urticaria, contact urticaria syndrome is a particular variety. In these patients, appearance of typical skin lesions is preceded by contact of the skin and mucous membranes with various inhaled allergens, nutrients or contact details. Furthermore, symptoms connected with contact urticaria syndrome are characterized by gradual, stepwise waveform, which can be easily generalized - patients may develop systemic symptoms similar to those found in the angioedema, asthma or anaphylactic shock. It is an attribute of contact urticaria syndrome in the course of which potentially life-threatening symptoms may develop after contact of the skin with the allergen. The underlying mechanisms are poorly understood; both immunological and non-immunological mechanisms are taken into account, therefore contact urticaria syndrome can be classified into two categories - allergic and non-allergic. An intriguing phenomenon seems to be the immediate reaction after exposure to low molecular weight allergens - haptens, such as metals, which are usually the cause of delayed allergic reactions. Diagnosis is based on clinical presentation indicating a coincidence of the onset of allergy with contract with allergen, and helpful exposure tests. Treatment consists of supportive antihistamines and corticosteroids - locally and systemically. In the case of anaphylaxis, appropriate treatment intensification of the integration of pressor amines and hydration is necessary. It is also regarded that prevention is advisable, which consists of relevant information to avoid situations connected with contact with well-known factors. In this paper we describe a case of a 57-year-old female admitted to the Department of Internal Medicine, Geriatrics and Allergology, Medical University in Wroclaw to undergo diagnostic tests of chronic urticaria and angioedema. According to information obtained from the clinical presentation and after the diagnostic procedures, contact urticaria syndrome due to exposure to metals was diagnosed.

Clinical characterization and IgE profiling of birch (Betula verrucosa)--allergic individuals suffering from allergic reactions to raw fruits and vegetables

BACKGROUND

Hypersensitivity to raw fruits and vegetables is often associated with respiratory allergy to birch (Betula verrucosa) pollen and is considered to be the most prevalent form of food allergy in adults sensitized to birch pollen.

OBJECTIVE

The aim of the study was to investigate the association of clinical allergy and IgE profiles in individuals with birch pollen allergy and hypersensitivity to raw fruits and vegetables.

METHODS

A total of 59 adults with clinical and skin prick test confirmed birch pollen allergy were included in the study. All the subjects were interviewed by using a structured questionnaire and were examined in vivo by the open test, with the appropriate fruits and vegetables. ImmunoCAP and ImmunoCAP ISAC were used as in vitro diagnostics to assess sensitization profiles for each individual, and principal components analysis was used to analyze the IgE data sets.

RESULTS

Of 59 individuals, 54 (92%) had positive prick-prick test with raw potato, carrot, apple, and/or hazelnut, and the skin prick test was always positive when the corresponding skin challenge was defined as positive. Specific IgE in the ImmunoCAP and inhibition assays with rMal d 1 and rBet v 1 demonstrated that Bet v 1 is driving the sensitization against pathogenesis related-10 proteins. However, positive IgE in vitro results could not be used to predict clinical reactivity to raw fruits and vegetables.

CONCLUSIONS

The present study showed that component-based IgE profiling does not enhance the diagnostic potential in case of pollen-food syndrome, which may be associated with other as yet unidentified components.

'I've got hay-fever and my mouth is stinging!'

A case of oral allergy syndrome is presented. Crossreactivity of pollens with some fruit/vegetables causes immediate IgE-mediated symptoms localised to the mouth. Diagnosis is suspected from positive skin prick testing in the presence of a suggestive history. Management is by allergen avoidance. In serious and refractory cases, referral to a regional allergy clinic is recommended.