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Allergic reactions represent a complex interplay between the immune system and environmental antigens, leading to a spectrum of clinical manifestations. These reactions are primarily classified into four types based on the Gell-Coombs classification, with Type I hypersensitivity being the most common. This immediate response is mediated by immunoglobulin E (IgE) antibodies and can result in acute conditions such as anaphylaxisâa life-threatening systemic reactionâas well as chronic conditions like allergic asthma and atopic dermatitis (Voisin et al., 2017; Ab, 2018; Kotb, 2022). The underlying pathophysiology involves the activation of mast cells and basophils, which release inflammatory mediators such as histamine, leukotrienes, and cytokines, thereby producing the clinical symptoms observed in allergic individuals (Durrani et al., 2024; LĂłpezâSanz et al., 2021; Radtke & Voehringer, 2023).
| Type | Mechanism | Onset | Key Mediators/Cells | Clinical Examples |
|---|---|---|---|---|
| Type I | IgE-mediated immediate reaction | Minutes | IgE, mast cells, histamine â, leukotrienes, cytokines | Anaphylaxis, allergic rhinitis, asthma, atopic dermatitis |
| Type II | Antibody-mediated cytotoxic reaction | HoursâDays | IgG/IgM, complement activation, opsonization | Hemolytic anemia, Goodpasture syndrome, some drug reactions |
| Type III | Immune complex-mediated reaction | HoursâDays | Immune complexes, complement, neutrophils | Serum sickness, Arthus reaction, certain autoimmune conditions |
| Type IV | T-cell mediated delayed reaction | 48â72 hours | T lymphocytes, macrophages | Contact dermatitis, tuberculin reaction, chronic transplant rejection |
In the primary care setting, effective triage is essential for the prompt identification and management of allergic reactions. Given that all our transactionsâboth clinical and administrativeâare streamlined through a single point of care, primary care providers must be adept at distinguishing between reactions that necessitate urgent intervention and those that can be managed in an outpatient environment. The sensitization phase of an allergic reaction begins when the immune system is first exposed to an allergen, leading to the production of allergen-specific IgE antibodies. Upon re-exposure, these antibodies trigger the degranulation of mast cells and basophils, releasing inflammatory mediators that cause symptoms such as itching, swelling, and bronchoconstriction (Ab, 2018; Salazar & Ghaemmaghami, 2013; Sutanto, 2024). T-helper cells, particularly Th2 cells, play a pivotal role in orchestrating this immune response by promoting IgE production and recruiting additional immune cells to the site of allergen exposure (Kotb, 2022; Kudrin & Rebane, 2023).
What symptoms are you experiencing?
Have the symptoms:
Have you been exposed to any known allergens?
Have you had a similar reaction before?
Do you have difficulty breathing?
Are you experiencing hoarseness or difficulty speaking?
Have you had swelling in your mouth, lips, tongue, or throat?
Are you feeling lightheaded, dizzy, or faint?
Do you have a rapid or irregular heartbeat?
Have you lost consciousness?
What makes the symptoms better or worse?
Describe the nature of your symptoms (e.g., sharp pain, burning, tingling).
Where are your symptoms located? Do they spread?
On a scale of 1 to 10, how severe are your symptoms?
Have the symptoms changed over time?
Do you have a history of allergies?
Have you been diagnosed with asthma, eczema, or other allergic conditions?
Are you currently taking any medications, including antihistamines or epinephrine?
Have you previously needed an epinephrine injection (EpiPen) for an allergic reaction?
Are your symptoms affecting your ability to work, study, or perform daily activities?
Based on your symptoms, select the most applicable severity level:
Is there anything else you would like to add about your symptoms or concerns?
Physical Examination Findings:
Interventions provided (if applicable):
Recommended follow-up action:
For primary care practitioners, understanding these mechanisms is crucial not only for accurate diagnosis but also for effective triage. Mild reactions, such as allergic rhinitis or urticaria, can often be managed conservatively, whereas severe reactions like anaphylaxis require immediate and aggressive treatment to prevent rapid progression to cardiovascular collapse or respiratory failure (SokoĆowska et al., 2021). Moreover, chronic allergic conditions such as asthma can lead to significant morbidity and potential long-term pulmonary damage if not adequately controlled (Voisin et al., 2017; OâKonek et al., 2019). The psychological impact of living with allergiesâincluding anxiety and avoidance behaviorsâfurther underscores the need for a comprehensive, patient-centered approach in primary care settings (Warrington et al., 2018; Palm et al., 2012).
