Dermatology and Skin Diseases (154)Asthma and respiratory diseases (134)Urticaria and Related Conditions (109)Allergic Rhinitis and Sensitization (83)Hidradenitis Suppurativa and Treatments (82)
Leth-Møller KB, van Hage M, Apostolovic D, Sørensen JA, Vestergaard C, et al.
Allergy •
Alpha-gal syndrome is a novel food allergy to the oligosaccharide galactose-α-1,3-galactose (alpha-gal) present in mammalian meat. Tick bites are considered an important route of sensitization to alpha-gal. Data on alpha-gal sensitization in the general population is scant. We utilized a unique data source of repeated population-based health examination studies to assess prevalence, time trends, risk factors, and characteristics of alpha-gal sensitization. Alpha-gal sensitization was assessed in >11.000 adults from four health examination studies of randomly invited residents in the Copenhagen region conducted in 1990-1991, 2011-2012, 2012-2015, and 2016-2017. Alpha-gal sensitization was defined as serum specific IgE (sIgE) to alpha-gal ≥0.1 kU/L; ≥0.35 kU/L; ≥0.7 kU/L; ≥3.5 kU/L. The population was characterized according to genetically determined ABO blood group, aeroallergen sensitization, and pets at home. The prevalence of sIgE to alpha-gal ≥0.1 kUA/L was 1.3% in 1990-1991, 3.7% in 2012-2015 and 3.2% in 2016-2017. Of those sensitized to alpha-gal >97% reported to consume red meat at least once a week, even for sIgE to alpha-gal ≥3.5 kU/L. Male sex, older age, aeroallergen sensitization, cat at home, and blood group A were associated with increased odds of alpha-gal sensitization. The known protective effect of blood group B was confirmed. In this general adult population, the prevalence of alpha-gal sensitization had doubled from 1990-1991 to 2016-2017. This could potentially be due to increased tick exposure and an increased atopic predisposition.
Leth-Møller KB, Hansen FR, van Hage M, Thomsen SF, Linneberg A, et al.
The journal of allergy and clinical immunology. Global •
The α-gal syndrome is a food allergy to galactose-α-1,3-galactose present in mammalian meat; it usually develops after tick bites. Despite being considered an emerging health problem, little is known about the geographic risk factors and patterns of α-gal sensitization. The aim of this study was to assess geographic clusters of α-gal sensitization and determine whether distance from home address to the forest and tick abundance are risk factors for α-gal sensitization in a Danish adult population. We utilized 3 population-based health examination studies that were conducted in 2011-2017 and covered a total of 8742 participants living in a suburban area. All participants were screened for a level of serum-specific IgE to α-gal of 0.1 kU/L or higher. Their home addresses were linked with CORINE Land Cover data and a tick prediction model. The associations of (1) distance to the forest and (2) tick abundance with α-gal sensitization were assessed by using multivariable logistic regression. There were 344 cases of galactose-α-1,3-galactose-specific IgE level being 0.1 kU/L; we identified 1 geographic cluster of cases. For every 1 km closer a participant lived to the forest, the odds ratio of α-gal sensitization was 1.09 (95% CI = 1.05-1.13). There were no associations between predicted tick nymph abundance and α-gal sensitization. In a general, individuals residing in a suburban area had 9% higher odds of being sensitized to α-gal the closer they lived to a forest, thus supporting exposure to ticks as a risk factor for sensitization to α-gal.
Pedersen HST, Sørensen JA, Madsen F, Linneberg A, Leth-Møller KB, et al.
Clinical and translational allergy •
Little is known about α-gal (galactose-α-1,3-galactose) sensitization in patients with chronic urticaria (CU). The aim of this study was to examine the prevalence, predictors and clinical relevance of α-gal sensitization in patients with CU. Two consecutive cohorts of newly referred patients with CU from a primary care allergology practice and a tertiary hospital dermatology department, plus a control group with allergic disease, but not CU, from the allergology practice, were interviewed and screened for α-gal sensitization (serum specific-IgE ≥0.35 KU/L). Of 733 patients included, 21 (5.6%) and 11 (3.9%) of CU patients from private practice and hospital, respectively, were α-gal sensitized. In total, 8 patients (38.1% of sensitized patients, and 2.1% of all CU patients) from private practice, and 2 patients (18.2% of sensitized patients, and 0.7% of all CU patients) from hospital, had clinically relevant α-gal allergy. In private practice, male sex (47.6 vs. 24.7%), p = 0.020, obesity (33.3 vs. 23.6%), p = 0.302, and frequency of angioedema (61.9 vs. 51.4%), p = 0.350; and in hospital, male sex (72.7 vs. 27.9%), p = 0.003, and high total immunoglobulin E (median 168 vs. 70.5 KU/L), p = 0.022 were associated with α-gal sensitization. α-gal sensitization is observed in a small fraction of CU patients with only few patients experiencing clinically relevant sensitization. Certain patients, particularly from primary care, may constitute a relevant population for aimed testing.