Asthma and Allergens
Jonathan A. Bernstein, Mark L. Levy in Clinical Asthma, 2014
Asthma is a heterogeneous disease that is influenced by multiple factors including the environment, genetics, pollution, infection, and diet. Atopy, defined as a predisposition to developing allergic sensitization, is a strong predisposing factor for the development of asthma, and for over two decades, there has been increasing evidence that specific allergens can have a causative role in the development of asthma.1,2 Environmental allergen sensitivity can also play an important role in the severity and treatment of asthma. The percentage of patients with asthma sensitized to ≥1 environmental allergen approaches 80%, and atopy may be the causative factor in over 50% of asthma cases.3 An increased exposure to allergens in sensitized individuals can lead to more asthma morbidity and increased health-care utilization.4–6 While many allergens are found indoors, the primary aeroallergens to which asthmatics are sensitized include house-dust mites, cats, dogs, mice, cockroaches, and mold (Table 10.1). This chapter will describe specific indoor allergens, highlighting their roles in asthma, and discuss strategies for their avoidance and environmental remediation.
Epidemiology and research
Greta Thornbory, Susanna Everton in Contemporary Occupational Health Nursing, 2017
The individuals in the three groups were examined and had blood tests to detect sensitisation, on commencement and then every 1–2 years depending on the plant. The findings were that OAA exposure is associated with frequent symptoms of the eyes and airways in a dose–response-related manner. Symptoms appeared even at mean exposure levels as low as <10 μg/m3. From this work an occupational exposure threshold level of <5 μg/m3 was proposed. The study also found that smoking and atopy may affect the symptoms. Atopy involves the capacity to produce immunoglobulin E in response to common allergens, a genetic tendency to develop the classic allergic diseases – atopic dermatitis, allergic rhinitis (hayfever) and asthma.38
Chronic erythematous rash and lesions on trunk and limbs
Richard Ashton, Barbara Leppard in Differential Diagnosis in Dermatology, 2021
Atopy means an inherited predisposition to eczema, asthma or hay fever, and atopic individuals may have one or all of these manifestations. It is becoming recognised that an inherited defective skin barrier is important in the cause of the eczema. The protein filaggrin helps bind keratin fibres in the stratum corneum, and this protein has been found to be defective in atopic eczema. The result of this is that corneocytes are deformed, natural moisturising factors are reduced and an increase in skin pH promotes inflammation. This defective barrier results in loss of water, dryness of the skin and penetration of irritants and allergens such as house dust mite, pollen and bacteria. The developing immune system in infants, becomes unbalanced with TH-2 lymphocytes and cytokines predominating over TH-1 cells. A vicious circle develops where the inflammation reduces the barrier, allowing penetration of irritants and allergens (especially bacteria), which causes further inflammation. Autoimmunity and the production of IgE antibodies is likely to be a by-product of these factors.
Etiology of posterior subcapsular cataracts based on a review of risk factors including aging, diabetes, and ionizing radiation
Published in International Journal of Radiation Biology, 2020
Richard B. Richardson, Elizabeth A. Ainsbury, Christina R. Prescott, Frank J. Lovicu
Atopy is the genetic disposition to allergic sensitization and recurrent or chronic inflammatory disorders. A prominent concept underlying atopy is the atopic march a process initiated by atopic dermatitis (eczema) in infants, progressing to allergic rhinitis (hay fever), and leading to asthma later in childhood: the so-called atopic triad (Johansson and Hershey 2018). In a study of 100 patients with PSCs, 33% of PSCs were of spontaneous or unknown etiology, with the most common predisposing risk factor being atopy (31%) (Vasavada et al. 2004). For patients with atopic dermatitis, PSCs and ASCs have been reported; these cataract types are linked to chronic ocular inflammation and oxidative stress (de Iongh et al. 2005; Shu et al. 2017). Corticosteroid therapy for atopic dermatitis is a confounding factor for PSC (Richer et al. 2001; Bair et al. 2011). A primary defect in the epithelial barrier causing impaired skin barrier function is proposed to have an important role in initiating the atopic triad (Zheng et al. 2011; Johansson and Hershey 2018). Perhaps this atopic epithelial defect could also compromise the function of non-skin epithelial barriers, including LECs, thereby increasing the risk of PSC cataractogenesis.
Comorbidity identification and referral in atopic dermatitis: a consensus document
Published in Journal of Dermatological Treatment, 2022
Javier Ortíz de Frutos, Gregorio Carretero, Raul de Lucas, Susana Puig, Esther Serra, Susana Gómez Castro, Francisco Rebollo Laserna, Estíbaliz Loza, Juan Francisco Silvestre-Salvador
Concerning atopic allergy: In AD, at the first visit/s and periodically during follow-up, the following comorbidities should be actively ruled out: asthma, allergic rhinitis, conjunctivitis, food allergy, eosinophilic esophagitis, and nasal polyposis (LE 5; GR D; LA 92%)Patient-reported atopic comorbidities should be carefully evaluated, given that they are not always correctly diagnosed (LE 5; GR D; LA 100%)Data on family atopic conditions must be collected (LE 5; GR D; LA 92%)Should any atopic comorbidity be suspected, the patient must be referred to the corresponding specialist or primary care physician (LE 5; GR D; LA 100%)
Upper airway and skin symptoms in allergic and non-allergic asthma: Results from the Swedish GA2LEN study
Published in Journal of Asthma, 2018
Mary Kämpe, Maria Vosough, Andrei Malinovschi, Mohammad Alimohammadi, Kjell Alving, Bertil Forsberg, Jan Lötvall, Roelinde Middelveld, Barbro Dahlén, Christer Janson
One of the strengths of this Swedish multi-centre cohort lies in the quality of the standardised GA2LEN survey data collected, the population-based design and the age range from 17 to 76 years, i.e. also including older asthma patients who are of special concern and much less studied. In addition to questions validated by the GA2LEN, subjects had a clinical follow-up and the investigated Swedish cohort can be regarded as relatively homogeneous, as data from the centres are consistent. Another strength of this cross-sectional study is the simultaneous evaluation of asthma with upper airways and skin allergy, as well as risk factors for allergic and non-allergic asthma in a large population sample. Naturally, these data must be interpreted with care, especially when studying associations between complex and multifactorial diseases, as associations at individual level can differ due to confounding factors and exposure is not fully assessed. The division of asthma groups into allergic and non-allergic is traditionally based on the concomitant presence of atopy, i.e. skin test positivity for at least one aeroallergen in epidemiological studies. It is, however, known that the presence of atopy alone cannot be used to divide asthmatics into the allergic and non-allergic phenotypes [50], as atopy can be a co-morbidity and without any causal link to asthma. The definition of CRS is based on questionnaire, but this definition has been validated against objective measurements [51].
Related Knowledge Centers
- Allergen
- Allergic Rhinitis
- Atopic Dermatitis
- Heredity
- Immunoglobulin E
- Type I Hypersensitivity
- Hypersensitivity
- Allergy
- Immune Response
- Pediatrics