A 16-year-old boy comes to the clinic with the chief complaint of a sore throat for three days. Denies fever or chills. PMH negative for recurrent colds, influenza, ear infections, or pneumonia. NKDA or food allergies. Physical exam reveals temp of 99.6 F, pulse 78, and regular respirations of 18. HEENT normal with the exception of reddened posterior pharynx with white exudate on tonsils that are enlarged to 3+. Positive anterior and posterior cervical adenopathy.
Rapid strep test performed in office was positive. His HCP wrote a prescription for amoxicillin 500 mg PO q 12 hours x 10 days disp #20. He took the first capsule when he got home and immediately complained of swelling of his tongue and lips and difficulty breathing with audible wheezing. 911 was called and he was taken to the hospital, where he received emergency treatment for his allergic reaction.
In the aforementioned case study, the patient presented with acute pharyngitis. Pharyngitis refers to the inflammation of mucus membranes of the oropharynx. Manifestations of uncomplicated pharyngitis include fever, painful cervical adenopathy, tonsillar exudates, and pharyngeal erythema (Wolford et al., 2022). It is predominantly caused by viral or bacterial infectious processes. A positive rapid strep test, in his case, favors a bacterial etiology.
According to Wolford et al. (2022), Group A beta-hemolytic streptococci is the most common cause of bacterial acute pharyngitis and accounts for up to 36% of the cases. Subsequently, the boy has been prescribed antibiotics, principally amoxicillin which is recommended for bacterial eradication in patients with strep pharyngitis. Upon taking the first capsule, the patient develops an immediate hypersensitivity reaction.
The patient in the case study above is allergic to penicillin. Type 1 hypersensitivity reactions include atopic diseases, which run in families. Drug hypersensitivity reactions can be allergic or non-allergic. However, these reactions usually occur as a result of cumulative interaction and interplay of various environmental and genetic factors.
For instance, more than half of children born in atopic families develop an allergic disease as opposed to one in five children with no family history of allergies (Amo et al., 2019). Additionally, various genes act diversely in different families to predispose to drug hypersensitivity reactions. For instance, the PHF11 gene on chromosome 13q14 has been linked consistently with drug hypersensitivity reactions.
The patient presented with swelling of lips and tongue, difficulty breathing, and audible wheezing. Swelling of the lips and tongue are characteristics of allergic angioedema. According to Justiz Vaillant et al. (2022), allergic angioedema is a type 1 hypersensitivity reaction and can be triggered by foods such as nuts and medications such as penicillin.
In this scenario, the patient has an exaggerated immune response in response to amoxicillin. Severe angioedema may progress to anaphylaxis. The difficulty in breathing and audible wheezing are a result of histamine-mediated bronchoconstriction. If not treated, the patients usually develop anaphylactic shock, which is life-threatening and may lead to death.
According to McCance and Huether (2019), type 1 hypersensitivity reactions are IgE- mediated and involve the release of large amounts of histamines and later leukotrienes by mast cells. Immune cells that are involved in this allergic reaction are T helper cells of types 1, 2, and 17. T helper 1 cells produce IL-2 and interferon-gamma and enhance a cell-mediated immune response, while T helper 2 cells produce IL-4 and IL-13, which enhance the production of antigen-specific-IgE.
Meanwhile, T helper 17 cells produce IL-17, IL-21, and IL-22. The drug is presented to these T cells via dendritic cells. Finally, the antigen binds to TCR receptors on the T cells and activates these immune cells (McCance & Huether, 2019).
Gender and other characteristics such as age, genetics, geography, and race influence the distribution of allergic diseases such as hypersensitivity reactions. For instance, most of these reactions are highly prevalent in childhood. In the United States, Puerto Ricans have the topmost prevalence, followed by blacks, whites, Asians, and ultimately Mexicans.
References
Amo, G., Martí, M., García-Menaya, J. M., Cordobés, C.
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