The case presented is a 16-year old boy with strep throat. This was suspected based on presenting symptoms of reddened posterior pharynx with white exudate on tonsils, swelling of tonsils, and anterior and posterior cervical adenopathy. This was confirmed by a rapid strep test. All of this presents as a common diagnosis of strep throat, and the healthcare provider prescribed the typical course of treatment. However, the patient experiences an immediate reaction to the medication and needs to be given emergency treatment for his allergic reaction. While there are no known factors that can predict amoxicillin allergy in children, a family history of a drug allergy may indicate a potential allergy (Faitelson et al., 2018). Family history was not presented in the case study; however, it was noted that the patient himself exhibited no known drug allergies, therefore there was no reason to suspect this patient would have an allergic reaction to the amoxicillin. After taking the amoxicillin, the patient is presenting with an immediate hypersensitivity reaction (Justiz-Vaillant & Zito, 2019; McCance & Huether, 2019; Soo, 2018).
Strep throat is caused by streptococcus bacteria, which is spread through droplet contact. Streptococcal pharyngitis has a short incubation period and presents as red, painful throat, swollen and pus-filled tonsils, enlarged cervical lymph nodes, and fever (Thai et al., 2018). The inflammation present in the tonsils is a result of the body’s immune response. The exudate present on the tonsils also results from the body’s immune response, as the pus contains dead cells, tissues, and bacteria as byproducts of phagocytosis (McCance & Huether, 2019; Soo, 2018).
There is a strong genetic link regarding IgE response to antigens or allergens (Soo, 2018). The case study presented no known drug allergies for the patient but does not list family medical history, so this information is not known. Most diseases, even when a genetic component is present, have both genetic and environmental aspects (McCance & Huether, 2019). While females are more susceptible to experiencing autoimmune disorders, the type I immediate hypersensitivity immune reaction presented in this case study does not fall under that category (McCance & Huether, 2019; Soo, 2018). One consideration for genetic factors is the increased serum tryptase levels in those with alpha tryptasemia. Individuals with alpha tryptasemia experience hypersensitive reactions and are often associated with systemic mastocytosis conditions (Macharadze, 2021). This information is not presented in this case study and is therefore unknown at this time.
This patient is experiencing an immediate hypersensitivity reaction to the amoxicillin medication, which is a type I or anaphylactic response (Justiz-Vaillant & Zito, 2019). When the patient ingested the amoxicillin, the body viewed the drug as an antigen. Upon exposure to the antigen, B cells mature into plasma cells, which produce IgE antibodies. These IgE antibodies then bind to specific receptors on mast cells, which then degranulate and release pro-inflammatory mediators, including histamine (Soo, 2018). Histamine causes vasodilation and subsequent hypotension, bronchoconstriction, and increased vascular permeability (McCance & Huether, 2019). The increased vascular permeability allows for fluid to leave the vasculature and enter the interstitial space, resulting in inflammation, which was evidenced by the patient experiencing swelling in his tongue and lips. The production of histamine also resulted in bronchoconstriction, which presented in difficulty breathing and auditory wheezing in the patient (McCance & Huether, 2019; Soo, 2018). The difficulty breathing may have also been exacerbated by an inflammatory response in the throat, as the patient was also experiencing swollen tongue and lips.
References
Faitelson, Y., Boaz, M., & Dalal, I. (2018, July). Asthma, family history of drug allergy, and age predict amoxicillin allergy in children. Journal of Allergy and Clinical Immunology, 6(4), 1363-1367. https://doi.org/10.1016/j.jaip.2017.11.015
Justiz-Vaillant, A. A. & Zito, P. M. (2019). Immediate hypersensitivity reactions. In StatPearls. StatPearls Publishing.
Machardze, D. S. (2021, December). Mast cells and tryptase. Modern aspects. Medicine Immunology, 23(6), 1271-1284. https://doi.org/10.15789/1563-0625-MCA-2193
McCance, K. L. & Huether, S. E. (2019). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Mosby/Elsevier.
Soo, P. (2018, July 28). Pathophysiology Ch 10 alterations in immune function [Video file]. https://www.youtube.com/watch?v=Jz0wx1-jTds
Thai, T. N., Dale, A. P., & Ebell, M. H. (2018, June). Signs and symptoms of group A versus non-group A strep throat: A meta-analysis. Family Practice, 35(3), 231-238. https://doi.org/10.1093/fampra/cmx072