Polish and French researchers have developed a new, simplified patch test capable of detecting the most common allergies in children within a EUREKA project. An estimated 1-2% of European adults and 5-7% of children suffer from some form of food allergy, according to the European Federation of Allergy and Airways Diseases Patients' Associations. Common food allergies among children include milk, corn, soy, nuts and house dust mites. 'In the past decade, food allergies have become a major point of concern for paediatricians,' explains Pierre-Henri Benhamou of France's DBV Technologies, one of the project partners, 'especially those treating very young children. Specifically, there has been a steady increase in the number of cases, a trend confirmed by statistics of the French drug agency showing the frequency of food allergies almost doubling over the last 10 years.' Reactions to foods are usually rapid, appearing within an hour (or sometimes even seconds) of consumption. However in recent years, allergies have started to evolve, presenting delayed reactions, with symptoms only appearing four hours after eating. 'These allergies are caused by foods that form the base of the day-to-day diet, and to which the patient becomes only gradually sensitised. Unlike the more traditional forms of allergy, the delayed forms pose important problems in terms of diagnosis,' says Dr Benhamou. To tackle both types of allergies, the researchers developed a patch test called DIALLERTEST, which is directly and painlessly applied onto a child's back. Another patch, with no irritant, is also applied as a control. Patches are then removed 48 hours later and swollen and red skin underneath the first patch denotes an allergic reaction. The DIALLERTEST differs from other allergy patch tests in that it does not use any additive or wet substance to hold the suspected allergen in place. Instead the allergen is applied to the patch in a dry powder formulation using electrostatic forces. Once applied to the surface of the skin, occlusion induces hydration and dilatation of pores, which favour the rapid and sustained flow of the allergen into the skin. 'This represents an important simplification of the patch test,' explains Dr Benhamou. 'With this method, we can maintain much tighter control over the quantity of allergen delivered. This means a more measurable and reproducible reaction, and, ultimately, more reliable and standardised screening for cow's milk protein allergy. This also allows doctors to keep allergens in their best reactive state, the powdered form.' The new diagnostic test has attracted much interest from the pharmaceutical industry, with a world leader in infant nutrition agreeing to commercialise the product.