From the Guidelines
No, atopic and allergic are not the same, though they are closely related. Atopy refers to a genetic predisposition to develop allergic diseases such as asthma, eczema (atopic dermatitis), and allergic rhinitis, as defined in the European position paper on rhinosinusitis and nasal polyps 2020 1. Someone who is atopic has an inherited tendency to produce excessive IgE antibodies in response to common environmental allergens. In contrast, the term allergic describes the actual immune response that occurs when someone encounters an allergen to which they are sensitized. Key differences between atopic and allergic include:
- Atopy is a genetic tendency to develop allergic diseases, whereas allergic refers to the immune response itself
- Atopic individuals often experience multiple allergic conditions simultaneously, requiring more comprehensive management approaches
- Not all allergic reactions occur in people with atopy, as anyone can develop an allergy to certain substances, such as poison ivy or drugs. The distinction between atopic and allergic matters clinically because it informs the approach to diagnosis, treatment, and management of allergic conditions, with atopic individuals potentially requiring more tailored and multifaceted care, as suggested by the 2020 European position paper on rhinosinusitis and nasal polyps 1.
From the Research
Definition of Atopic and Allergic Terms
- The terms "atopic" and "allergic" are related but not exactly the same, as indicated by studies 2, 3, 4.
- Atopy refers to an individual or familial tendency to produce IgE antibodies in response to low doses of allergens, often accompanied by symptoms of asthma, rhino-conjunctivitis, or eczema/dermatitis 4.
- Allergy involves a hypersensitivity reaction initiated by an immunological mechanism, which can be further categorized as IgE-mediated or non-IgE-mediated 4.
Distinction Between Allergic and Nonallergic Conditions
- Research distinguishes between allergic and nonallergic forms of atopic diseases, such as asthma and dermatitis 2, 3.
- The presence of elevated total serum IgE levels is a characteristic of allergic atopic diseases, whereas nonallergic forms may exhibit normal IgE levels 2.
- Studies have identified clinical similarities and differences between allergic and nonallergic asthmatics, including factors such as age, sex, and nasosinusal involvement 3.
Terminology and Classification
- The European Academy of Allergology and Clinical Immunology has proposed a revised terminology for allergic and allergy-related reactions, which includes the categorization of conditions as "allergic" or "nonallergic" 4.
- The terms "extrinsic" and "intrinsic" asthma are no longer recommended, and instead, the terminology of "allergic" or "nonallergic" asthma should be used 3, 4.
- Atopic diseases, such as atopic dermatitis, can be classified as allergic or nonallergic, depending on the presence of IgE antibodies and other factors 2, 4.