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Oral mite anaphylaxis (pancake syndrome) caused by storage mite Acarus siro and its treatment with allergen immunotherapy
Abstract
A 10-year-old atopic patient with asthma, peanut, and house dust mite allergy developed frequent episodes with symptoms including abdominal pain, nausea, vomiting, dizziness, drop of blood pressure, and occasionally shortness of breath and wheezing. After detailed diagnostics including an ISAC test and several other specific IgE blood tests, which could not explain the symptoms, the patient tested positive for specific IgE to Acarus siro (flour mites) (9.2 kU/L). As no oral food challenge with Acarus siro was available, the patient’s family implemented avoidance measures by storing food containing flour in the refrigerator, and the patient started subcutaneous immunotherapy (SCIT) with Depigoid Acarus siro. The implementation of avoidance measures led to an immediate improvement of symptoms, and after 3 years of treatment, products containing flour, stored at room temperature, are tolerated again.
... However, these conditions are more commonly caused by parasites such as helminths. For allergies in particular, storage mites are implicated in "pancake syndrome", which is a host of allergic symptoms caused by reactions to mites infesting flour products with antihistamines used for the treatment of allergic conditions [50][51][52]. ...
Mites are highly prevalent arthropods that infest diverse ecological niches globally. Approximately 55,000 species of mites have been identified but many more are yet to be discovered. Of the ones we do know about, most go unnoticed by humans and animals. However, there are several species from the Acariformes superorder that exert a significant impact on global human health. House dust mites are a major source of inhaled allergens, affecting 10–20% of the world’s population; storage mites also cause a significant allergy in susceptible individuals; chiggers are the sole vectors for the bacterium that causes scrub typhus; Demodex mites are part of the normal microfauna of humans and their pets, but under certain conditions populations grow out of control and affect the integrity of the integumentary system; and scabies mites cause one of the most common dermatological diseases worldwide. On the other hand, recent genome sequences of mites provide novel tools for mite control and the development of new biomaterial with applications in biomedicine. Despite the palpable disease burden, mites remain understudied in parasitological research. By better understanding mite biology and disease processes, researchers can identify new ways to diagnose, manage, and prevent common mite-induced afflictions. This knowledge can lead to improved clinical outcomes and reduced disease burden from these remarkably widespread yet understudied creatures.
Idiopathic anaphylaxis (IA) remains a frustrating challenge for both patients and physicians. The aim of this paper is to focus on IA in pediatric ages and suggest possible diagnostic algorithms according to specific age ranges (infants, children, and adolescents). In fact, in a variable percentage of patients, despite extensive diagnostic tests, the cause of anaphylactic episodes cannot be identified. Moreover, the lack of a unanimous IA definition requires a careful and detailed diagnostic workup. Prompt recognition of signs and symptoms, especially in younger children, and an accurate clinical history often allow a choice of the most appropriate diagnostic tests and a correct differential diagnosis.
Purpose of review:
To present an update on the recent advances in the understanding of the mechanisms and practical management of oral mite anaphylaxis (OMA, pancake syndrome).
Recent findings:
Among novel observations regarding OMA, this review highlights the increased prevalence of aspirin/NSAID hypersensitivity inpatients affected by OMA, the association of OMA with exercise-induced anaphylaxis, the presentation of OMA simulating acute asthma, the occurrence of OMA in childhood, the high severity and lethal potential of OMA, the contamination of other foods, such as oat and corn flour with mites, and the simultaneous induction of OMA symptoms in more than one individual exposed to the same food source.
Summary:
OMA is a severe, potentially lethal, acute allergic condition that should be suspected whenever symptoms begin soon after the intake of mite-contaminated foods. Physician awareness on this clinical picture is of paramount importance to establish a correct diagnosis and to implement adequate preventive measures to help patients at risk to avoid its occurrence.
To present currently available information on oral mite anaphylaxis.
Oral mite anaphylaxis (pancake syndrome) is a new syndrome characterized by severe symptoms triggered by the intake of foods containing mites and their allergens. Breathlessness, face and/or laryngeal angioedema, wheezing, rhinorrhea, cough, dysphagia, and wheals are the most frequent clinical manifestations.
Pancake syndrome can occur in individuals at any age and in any geographical location. Foods made with wheat and corn flour, especially pancakes, are the most common inducers of the clinical picture. Both, domestic and storage mites have been incriminated. Increased physician awareness is required for early diagnosis and treatment, and for the prevention of future episodes in predisposed individuals.
A 48-year-old man was evaluated for anaphylaxis associated with ingestion of beignets prepared from a commercial mix. Microscopic examination of the patient's beignet mix revealed live Dermatophagoides farinae. Another unopened box from the same source was not infested. Skin test results to aeroallergens and foods, including all beignet mix ingredients, were positive only to D. farinae and D. pteronyssinus extracts. Skin prick test results to an infested mix extract (1:5 wt/vol) were also positive, but no reaction was observed with noninfested mix extract. ELISA inhibition studies demonstrated significant inhibition of the patient's serum binding to D. farinae strips by infected mix extract. Parallel inhibition curves were produced by the infested mix extract and a commercial D. farinae extract. Noninfested mix extract showed no inhibition. RAST analysis with beignet mix discs showed significant binding of the patient's serum IgE to infested mix discs but not to noninfested mix discs. RAST inhibition studies revealed more than 86% inhibition of binding of the patient's IgE to infested mix discs by infested mix extract and D. farinae extract. No inhibition was observed with noninfested mix or 5% fetal calf serum-phosphate-buffered saline. We conclude that the allergen to which the patient reacted was most likely D. farinae and that ingestion of D. farinae may cause anaphylaxis in sensitive persons.
Anaphylaxis after ingestion of flours contaminated with mites has been recently reported.
The study was designed to determine whether four-induced reactions in the absence of food sensitivity may result from mite contamination.
Patients with systemic reactions after ingestion of foods containing wheat flour and without food sensitivities were included in a prospective study. The flours were examined microscopically, and major Dermatophagoides allergens were quantified by monoclonal antibody techniques. Skin prick tests and IgE determinations to mites and flours were performed. Single-blind, placebo-controlled oral challenges were also performed.
Sixteen patients were included in our protocol. They showed respiratory allergies to dust mites (100%) and intolerance to acetylsalicylic acid (87%). Microscopic examination of four flours implicated in allergic reactions revealed a high degree of mite contamination: Dermatophagoides farinae in one case and Thyreophagus entomophagus in three cases. Our patients' skin test and specific IgE responses to the flours implicated in the reactions were positive. A high level of Der 2 was found in the flour infested by D. farinae. Three of six food challenges with contaminated flours resulted in systemic reactions. Good tolerance to control flours was shown in our patients.
Ingestion of foods contaminated with mites may induce systemic anaphylactic reactions in patients with respiratory allergy to mites.
Various mite species referred to collectively as house dust and storage mites are recognized worldwide as a cause of allergic airway disease. Our study aimed to investigate the frequency of sensitization and potential importance of mite species in farmers using a broad mite spectrum. A total of 86 German farmers with rhinitis and/or asthma were studied by skin prick testing and/or enzyme allergosorbent test (EAST) with the following mites: Blomia tjibodas, Blomia tropicalis, Blomia kulagini, Glycyphagus domesticus, Thyreophagus entomophagus, Euroglyphus maynei, Chortoglyphus arcuatus, Dermatophagoides pteronyssinus, Dermatophagoides farinae, Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, Acarus farris and Cheyletus eruditus. Sensitization to at least one mite species was detected in 51 patients (59%) by skin prick testing, and in 31 patients (36%) by EAST. The most frequent sensitizations determined by skin tests were found for the three Blomia species, E. maynei and G. domesticus. Twelve patients (14%) gave a positive EAST with the predator mite C. eruditus. A total of 22 patients gave positive EAST results with the Dermatophagoides species. We were able to document sensitization to C. arcuatus, E. maynei and T. entomophagus for the first time in Germany. A considerable proportion of the German farmers tested were sensitized to storage mites. The allergological potential of various mite species has been recognized, some for the first time. It was concluded that B. tjibodas, G. domesticus, C. arcuatus and C. eruditus in particular should be included in an allergy diagnosis. Further investigations into the clinical relevance of the sensitizations and possible cross-reactivity between the mite species are necessary.
Mite sensitivity is highly prevalent in tropical and subtropical regions, such as the Canary Islands.
To evaluate the clinical efficacy and safety of a depigmented polymerized allergen vaccine containing a 50% mixture of Dermatophagoides pteronyssinus and Dermatophagoides farinae.
Sixty-four patients participated in the study. It was prospective, double-blind, and placebo-controlled, with random allocation of patients to receive active treatment or placebo. The active group received a mixture of modified allergen extracts containing 50% D pteronyssinus and 50% D farinae; the control group received placebo. All individuals were diagnosed with mild/moderate asthma and rhinoconjunctivitis caused by sensitization to D pteronyssinus and D farinae. Bronchial provocation test (BPT) was considered the main outcome to document clinical efficacy.
Fifty-four patients completed the study. The active group experienced a significant improvement in BPT (P < .001), whereas the placebo group did not (P = .648). At the end of the study, 20 patients in the active versus 9 in the placebo group (P = .013; odds ratio, 5.71 [1.76, 18.51]) needed more than twice the amount of allergen to obtain a positive BPT. The median improvement in the active group over placebo was 53.76% in total symptom and 58.09% in medication scores.
Immunotherapy with a mixture of modified allergen extracts of D pteronyssinus and D farinae is safe and efficacious to treat mite-allergic asthma.
This immunotherapy modifies the natural course of the illness because it improves all clinical outcomes measured and prevents the worsening of specific bronchial hyperreactivity.