Obesity may be associated with allergic diseases

Obesity may be associated with allergic diseases (including atopy, asthma, and allergic rhinitis) in children.9, 10, 11 Furthermore, body mass index (BMI) may be associated with bronchial hyper-responsiveness.9, 12 Nevertheless, the relationship between histamine skin reactivity and BMI is poorly understood.
Methods
Results
Discussion There is an association between BMI and allergic diseases and bronchial hyper-responsiveness, but the factors influencing individual variations of histamine skin reactivity remain unknown.9, 10, 11, 12 Therefore, this study aimed to investigate the association between histamine skin reactivity and BMI and other clinical factors. The results showed that high skin reactivity to histamine was associated with high BMI. In addition, a novel finding of this study was that skin reactivity to histamine showed seasonal variation, with higher reactivity during summer or autumn. These associations should be considered for a better interpretation of the SPT. The SPT is a reliable method for the diagnosis of allergic diseases involving IgE (asthma, allergic rhinitis, food allergies, and atopic dermatitis). Even if histamine is the usual standard positive control for SPT, it is essential to fully understand histamine skin reactivity to properly interpret the results of the SPT. Indeed, there are considerable variations in the skin reactivity to histamine among individuals,4, 5, 6, 7, 8 but the reasons for these variations are not fully understood. In the present study, the wheal size to histamine was positively associated with BMI in children of 3–6 years of age, as supported by two previous studies,14, 15 but no mechanism can be determined based on these results. Nevertheless, some possible explanations can be extracted from the available literature. Mast Spironolactone sale are critical actors involved in allergic reactions since they are the main source of histamine.16, 17 In addition, mast cells are associated with obesity.16, 17 Serum tryptase is used to assess the number and activity of mast cells and is positively associated with BMI. Therefore, there is a possibility that the association between response to histamine and BMI could be mediated, at least in part, by the higher number and/or activity of mast cells due to obesity. Of course, other factors and mechanisms could be involved in this association, such as skin fragility associated with higher BMI. Indeed, obese diabetic mice have higher skin fragility compared to normal mice. In addition, skin blood flow increases with BMI, and obese individuals have increased skin redness after sodium lauryl sulfate stimulation. Previous reports showed that age, smoking, and atopy were associated with histamine skin reactivity,4, 21, 22 but these observations are controversial.23, 24 Some studies showed a significant association between obesity and allergic responses. Bibi et al. reported that obese children had higher frequencies of asthma, wheezing, and inhaler use. In addition, Peroni et al. reported that obesity was associated with asthmatic symptoms. Chinn et al. reported that BMI and bronchial hyper-responsiveness were closely associated. In an animal study, Malmlof et al. reported that histamine could play an important role in obesity, and that inhibiting the histamine receptor could decrease food intake, body weight, and plasma lipids. Visnovsky et al. reported that age and body weight were related to histamine reactivity in the tracheopulmonary contractile tissues. The present study was not designed to determine the mechanisms leading to higher skin reactivity to histamine. Nevertheless, data suggest that histamine levels can be increased by the release of substance P, resulting in neurogenic inflammation.30, 31, 32 Substance P is recognized as a target molecule for obesity.33, 34 Therefore, it could be hypothesized that increased levels of substance P in obesity could act as an allergic mediator through neurogenic inflammation, inducing greater histamine reactivity in obese patients.