10/11/2023 0 Comments Bee sting reaction![]() The BAT can identify markers present on the surfaces of drug-allergen activated basophils. įlow cytometric basophil activation test (BAT) can help diagnose immediate hypersensitivity to certain medications (I.e., beta-lactams, muscle relaxants, etc.). When assessing for anaphylaxis, the first steps are to evaluate the airway, breathing, circulation, and mentation. Patients that present with anaphylaxis may also experience episodes of loss of consciousness, nausea, vomiting, angioedema, hypotension, tachycardia, tachypnea, etc. The presence of "wheal-and-flare" (skin bump and redness) reactions are the hallmark of IgE mediated reactions. The most common chief complaint and physical symptoms may include rash, hives, erythema, pruritis, edema, flushing, bronchospasm, wheezing, rhinitis, and gastrointestinal symptoms such as abdominal cramping. The signs and symptoms exhibited in this type of reaction involve vasoactive mediators that are released by IgE bound mast cells and basophils. In general, a patient that presents with a type I hypersensitivity usually develops a reaction within one hour after exposure to an antigen. The presentation depends on the organs that are involved. ![]() A complete physical examination should also be performed. Medical history alone is not sufficient to diagnose an allergic response. Review of medical records and allergies, especially in patients who are unable to communicate Individuals can experience pruritis and local response of asthma or a systemic response of anaphylaxis. Pulmonary edema or general edema can also occur due to fluid shifting into interstitial space. This results in the degranulation of the cells and the release of histamine, proteolytic enzymes, and other mediators (i.e., prostaglandin, cytokines, leukotrienes, platelet-activating factors, macrophage inflammatory proteins, tryptase, etc.).Īs a result, there is increased vascular permeability, peripheral vasodilation, and smooth muscle contraction, which can manifest to increased mucous secretions, bronchospasm, abdominal cramping, rhinitis, and potentially hypovolemia or hypoxia. Subsequently, the free antigen induces the crosslinking of these mast cell and basophil bound IgE antibodies. T-cells then signal for stimulation of B-cells to produce IgE antibodies, which bind to the Fc receptors on mast cells and basophils. The reaction may be manifested in different areas of the body and may result in instances such as:Īllergens (or antigens) are presented to T-cells by Antigen-presenting cells (APCs) during the sensitization phase of Type I hypersensitivity. The allergens that result in a type I hypersensitivity may be harmless (i.e., pollen, mites, or foods, drugs, etc.) or more hazardous such as insect venoms. Type I hypersensitivities include atopic diseases, which are an exaggerated IgE mediated immune responses (i.e., allergic: asthma, rhinitis, conjunctivitis, and dermatitis), and allergic diseases, which are immune responses to foreign allergens (i.e., anaphylaxis, urticaria, angioedema, food, and drug allergies). However, the focus of this article will be on the classic Type I hypersensitivity reactions. ![]() that accounts for multiple components of the immune system and categorizes the reactions into seven parts. There has been a more recent classification introduced by Sell et al. T-cells or macrophages are activated as a result of cytokine release, leading to tissue damage. Type IV hypersensitivity is also known as delayed-type and involves of T-cell-mediated reactions.
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