Diagnostic approach for suspected pseudoallergic reaction to food ingredients

Abstract

Chronic urticaria, recurrent angioedema and non-allergic asthma have all been associated with pseudoallergic reactions to food ingredients. For atopic dermatitis and diseases of the gastrointestinal tract, this association is controversial. Pseudoallergic reactions can be elicited by additives as well as by natural food ingredients. An altered histamine metabolism may be associated with pseudoallergy. Acute urticaria or a short episode of angioedema is not an indication for exhaustive evaluation. If basic diagnostic screening is negative in chronic urticaria, a low-pseudoallergen diet can be considered. Skin and serological tests are not objective diagnostic parameters for pseudoallergic reactions. The severity of symptoms should be documented while the patient is on a low-pseudoaller-gen diet. Oral provocation with additives leads to reproducible symptoms only in a few cases. Therefore, if a low-pseudoallergen diet brings improvement, the patient is then exposed to a pseudoallergen-rich "super meal". After a positive reaction to the "super meal" the challenge with additives takes place in the form of collective group exposition. When the patient has asthma or a history of anaphylac-toid reactions, testing with individual substances in carefully increasing dosages is required. The suspicion of adverse reactions against histamine can be confirmed by a challenge with histamine dihydrochloride. In the case of respiratory symptoms, provocation by inhalation should be considered. Objectifying symptoms especially in gastrointestinal diseases is mandatory and should include double-blind placebo-controlled food challenge, if possible.

Consumption of Artificially-Sweetened Soft Drinks in Pregnancy and Risk of Child Asthma and Allergic Rhinitis

“…However, as these are rare events, establishing a causal link is complex and most of the current knowledge is based on case reports [42]. As food additives may cause allergic reaction, exposing subjects to a group of food additives, including sweeteners, has been recommended in screening for food allergy [43]. The word “food additives” covers a broad range of chemically unrelated substances and this approach highlights the general absence of mechanistic insight for several suspected allergens.…”

Lack of Association of Plasma Histamine with Diamine Oxidase in Chronic Idiopathic Urticaria

“…Excessive intake of histamine-rich food may induce an attack of urticaria, which is described as histamine-mediated pseudo-allergic reactions or pseudo-food allergies5. Pseudo-allergic reactions are defined as clinical reactions resembling allergic reactions without distinct immunologic sensitization6. As a result, some cases of CIU could be clinical manifestations of pseudoallergic reactions.…”

“…As a result, some cases of CIU could be clinical manifestations of pseudoallergic reactions. The main causes of pseudo-allergic reactions include not only drugs or contrast media, but also altered histamine metabolism6.…”

Trigger Factors, Allergens and Allergy Testing in Atopic Dermatitis

“…Pseudo allergic reactions are more known in the clinical context of urticaria and angioedema. To date no reliable laboratory or skin tests are available to diagnose pseudo allergy, so that for the identification of possible pseudo allergen trigger factors elimination diet and oral challenge are the norm (Reese et al, 2009 (Robinson & Smart, 2008& Goodwin, 2008& Kim, 2008. SPT in the diagnosis of FA in infancy is thought to be unreliable.…”