Of those with a positive food screen, 28% (13/46) had milk-IgE antibodies comprising 1.5% of the total group screened. Results Some 5.4% (46/857) of all subjects had a positive IgE antibody screen for food antigens. Of those with a positive food screen, 28% (13/46) had milk-IgE antibodies comprising 1.5% of the total group screened. The prevalence of milk-IgE was not statistically different between those with milk-related symptoms and those with no such symptoms. IgE antibodies for boiled milk were rare. All specific IgE antibody levels were low. Bloating was the only observed symptom in milk challenge tests. Conclusion IgE antibodies to cow’s milk were relatively rare in the adult population and were not indicative of milk protein allergy. The observed IgE levels were low and did not correlate with subjective milk-related symptoms. The measurement of milk-specific IgE in adults should be discouraged in outpatient clinics. Keywords: Abdominal symptoms, cow’s milk, food hypersensitivity, primary care Food and especially milk-related gastrointestinal problems are common in general practice. Positive reactions in IgE food screening are relatively common in adults. Milk-specific IgE antibodies are rare. Measurement of milk-protein IgE is not likely to give any additional information on milk-related symptoms in adults and is of little value in general practice. In clinical practice, concern regarding milk-related symptoms is common and often results Lapatinib (free base) in restriction in consumption of dairy products. Recently, we reported that more than 40% of adults in primary care suspect they have experienced gastrointestinal symptoms after milk ingestion [1]. Among the possible aetiological factors for milk-related symptoms, adult-type hypolactasia is frequent in populations with high dairy intake, the prevalence ranging from Lapatinib (free base) 4% to 60% in Caucasian populations [2]. In untreated coeliac sprue, another important trigger for milk-related gastrointestinal symptoms, Lapatinib (free base) villous destruction in the small intestine induces secondary hypolactasia Lapatinib (free base) [3]. Further, allergy to cow’s milk may induce gastrointestinal symptoms in children [4C6]. Hypersensitivity to milk, however, may occur in adults also, as has recently been reported in, for example, Australia [7] and Finland [8], [9], and hence may be one reason for milk-related gastrointestinal problems. Recently, we investigated children and adolescents with abdominal complaints and unexpectedly found food-specific IgE antibodies in up to 31% of the children undergoing upper gastrointestinal endoscopy [10]. This and the recent reports of an increase in triggers of IgE class switching and allergy development [11] raised the possibility that IgE positivity for food antigens has increased and may in some cases be associated with abdominal symptoms. In this study we evaluate the prevalence of IgE-type food antibodies and focus on milk antibodies in adults and their attribution to gastrointestinal symptoms related to milk. Material and methods Milk consumption and milk-related abdominal symptoms were screened in a large population of 1900 adults in primary healthcare during spring 2004 [1]. All consecutive working-age patients in five primary care centres who had a referral for blood withdrawal in the laboratory were given the opportunity to join the study. The targeted sample size of 2000 participants was almost reached during a three-month period. However, the number of non-participants was not registered. At blood sampling, the participants were asked to fill in a structured questionnaire on milk consumption and abdominal symptoms. Data on previous diagnosis of atopy was also requested. The response rate was high as 99% of the participants returned the questionnaire [1]. All participants who reported milk-related symptoms (n?=?756; 40% of those 1885 who filled in the questionnaire) were chosen for this study. A control group of 101 subjects was randomly selected from those who reported no milk-related symptoms (n?=?638). Of the 1885 participants, 491 did not answer the question on milk-related symptoms Il1a and they were excluded from the selection. Thus, the study group in this study comprised 857 adults (aged 18C64 years) who were screened for food-specific IgE. In addition, the subjects had been genotyped for adult-type hypolactasia [1], and screened for Lapatinib (free base) coeliac disease [12]. The Pharmacia CAP System was used for screening of specific IgE against major food allergens (wheat, codfish, peanut, egg (ovalbumin), soy-bean, cow’s milk). Values equal to or higher than 0.35 IU/l were considered positive. Those with a positive total screen were further screened for specific IgE to untreated skimmed milk (f2; milk-IgE) and boiled milk-IgE (f231; Pharmacia ImmunoCap System). All individuals with a positive milk-IgE test were invited for an open milk challenge test,.