Anaphylaxis Induced by Inhaling Guinea Pig Allergen: A Case Report and Clinical Implications
A 27-year-old male presented to the hospital with acute-onset wheezing, coughing with white phlegm, dyspnea, sneezing, rhinorrhea, nasal congestion, pruritus, conjunctival erythema, urticaria on both arms, abdominal pain, and dizziness. Symptoms emerged 10 minutes after bathing and drying his pet guinea pig. Initial treatment with cetirizine and systemic corticosteroids provided partial relief on the day of onset, with complete resolution by the following morning. The patient’s medical history included allergic rhinitis and eczema, with no prior food or drug allergies. His family history revealed paternal allergies to cheese and eggs. The patient had prolonged exposure to pets, including a cat (20 years), a dog (5 years), and a guinea pig (2 years). Physical examination findings included maculopapules, excoriations, and scabs on both legs, pale edematous nasal mucosa, and clear lung auscultation. A diagnosis of anaphylaxis, allergic rhinitis, and eczema was established based on clinical criteria.
Diagnostic Evaluation and Findings
Allergen testing revealed sensitization to multiple allergens. Skin prick testing demonstrated positive reactions to dust mites (++), house dust (+), and cats (++). Total serum IgE was elevated at 200 kU/L. ImmunoCAP-specific IgE (sIgE) testing further quantified sensitization: guinea pig (e6) sIgE levels were markedly elevated at 22.7 kU
A/L (grade 4), followed by Dermatophagoides pteronyssinus (d1, 10.6 kUA/L; grade 3), Dermatophagoides farinae (d2, 11.4 kUA/L; grade 3), and a mixed inhalant panel (hx2: h2, d1, d2, i6) at 12.7 kUA/L (grade 3). Cat dander (e1) sIgE was 0.89 kUA/L (grade 2). Sensitization to hamster (e84), rat (e87), mouse (e88), dog dander (e5), Aspergillus fumigatus (m3), and Alternaria alternata (m6) was undetectable (<0.35 kUA/L). Pulmonary function tests showed forced expiratory volume in 1 second (FEV1) at 88% predicted, FEV1/FVC ratio of 114%, and elevated fractional exhaled nitric oxide (FeNO) at 98 parts per billion (ppb).
Pathogenesis and Diagnostic Considerations
Anaphylaxis, a systemic hypersensitivity reaction affecting multiple organ systems, was diagnosed based on the involvement of cutaneous (urticaria), respiratory (wheezing, dyspnea), and gastrointestinal (abdominal pain) symptoms. The temporal association between guinea pig exposure and symptom onset, coupled with elevated sIgE to guinea pig allergen, confirmed this as the trigger. Notably, the patient’s prior exposure to cats and dogs did not provoke similar reactions, and no recent food or drug intake was reported. The rapid increase in airborne guinea pig allergen concentration during bathing and drying likely contributed to acute inhalational exposure.
The absence of provocation testing, avoided due to ethical concerns regarding anaphylaxis recurrence, underscores the reliance on clinical history and corroborative laboratory findings for diagnosis. This case highlights guinea pig allergens as a rare but significant trigger of anaphylaxis, particularly in sensitized individuals with concurrent atopic conditions such as allergic rhinitis and eczema. These comorbidities may lower the threshold for severe allergic reactions, as suggested by the patient’s elevated total IgE and polysensitization to multiple aeroallergens.
Epidemiological and Clinical Relevance
Anaphylaxis incidence ranges from 1.6% to 5.1%, with food allergens predominant in outpatient settings and medications more common in hospitalized patients. This case represents the first reported instance of guinea pig-induced anaphylaxis in China, expanding the spectrum of inhalational triggers. The rising prevalence of unconventional pets, including rodents, necessitates heightened clinical suspicion for novel allergens in patients with unexplained anaphylaxis.
The patient’s FeNO level (98 ppb) indicated significant eosinophilic airway inflammation, consistent with poorly controlled allergic asthma. Despite normal FEV 1 and FEV1/FVC ratio, elevated FeNO underscores the importance of monitoring airway inflammation in atopic individuals. The discordance between cat exposure history (20 years) and relatively low sIgE to cat dander (grade 2) suggests tolerance development, contrasting with acute sensitization to guinea pig allergens over a shorter exposure period (2 years).
Preventive and Therapeutic Implications
Management emphasized strict avoidance of guinea pig exposure, coupled with emergency epinephrine auto-injector provision. Long-term strategies included optimization of allergic rhinitis and eczema control through antihistamines, intranasal corticosteroids, and topical immunomodulators. The case underscores the need for comprehensive allergen testing in recurrent anaphylaxis, particularly when common triggers are excluded.
Public Health Considerations
The growing diversity of household pets necessitates public education on potential zoonotic allergens. Rodent allergens, including those from guinea pigs, are increasingly recognized as sensitizers in urban populations. Healthcare providers should inquire about exposure to exotic pets during allergy evaluations and consider cross-reactivity between rodent allergens. While this patient exhibited monosensitization to guinea pig, shared epitopes among rodent allergens warrant further investigation.
Conclusion
This case illustrates the critical role of detailed exposure history and advanced allergen testing in diagnosing atypical anaphylaxis triggers. Guinea pig allergens, though rarely reported, can provoke life-threatening reactions in sensitized individuals. The intersection of atopic predisposition, polysensitization, and novel allergen exposure creates a high-risk profile for severe hypersensitivity. Clinicians must remain vigilant to evolving patterns of pet ownership and their implications for allergic disease.
doi.org/10.1097/CM9.0000000000000971
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