Abstract | March 23, 2023

Sensitization to Rhizopus stolonifer and the Development of Allergic Conditions

Geetha Gowda, MS, BA

Scout M Treadwell, BA, Medical Student, 3rd Year, Tulane School of Medicine, New Orleans, LA; Maxwell Green, MS, Medical Student 3rd Year, Tulane School of Medicine, New Orleans, LA; Andrew McKernan, MD; John Carlson, MD, Pediatric Residency Program Director, Tulane School of Medicine, New Orleans, LA.

Learning Objectives

  1. Establish the significance of R. stolonifer and its association with allergic conditions.
  2. Demonstrate the importance of R. stolonifer as both an aeroallergen and the fungi implicated in Mucormycosis.
  3. Emphasize including R. stolonifer when testing for fungal sensitivities.

Introduction: The common bread mold, Rhizopus stolonifer, is implicated in serious fungal infections such as mucormycosis. The availability of extracts has led to the inclusion of R. stolonifer in screening tests used in the evaluation of patients with aeroallergen sensitization. However, sensitization to R. stolonifer and the development of allergic rhinitis and asthma is poorly studied. We performed a metanalysis to clarify the role of R. stolonifer in human airway hypersensitivity disorders. Methods: A systematic review was conducted using PubMed, Embase, and Web of Science using the search terms “Rhizopus stolonifer” AND rhinosinusitis OR asthma OR rhinitis OR conjunctivitis OR allergic fungal sinusitis OR allergic bronchopulmonary aspergillosis. Studies were included only if they used clinical data along with human sera. Results: Nine studies were included in this review. Findings included IgE mediated sensitization in both allergic rhinitis and asthma [1]. Additionally, one study reported asthmatic patients who initially tested negative to a standard panel of fungal aeroallergens that later tested positive when R. stolonifer and other fungi were included in the panel (n=44/454) [2]. Similarly, another study investigated sensitizations to thirty-five perennial allergens in asthmatic patients who previously had negative allergen testing [3]. 16% of asthmatic patients reported sensitivity to R. stolonifer despite previously being considered non-atopic (n=36/214) [3]. Interestingly, one case report studied two cases of allergic bronchopulmonary mycosis with positive sensitization to R. stolonifer after a negative IgE sensitization to Aspergillus fumigatus [4]. Conclusions: Although rare, sensitization to R. stolonifer is associated with allergic conditions, and should be evaluated, specifically in the context of apparent hypersensitivity disorders of the airway with negative work-up for more standard sensitizations.

 

References

  1. Klarić MŠ, Varnai VM, Calušić AL, Macan J. Occupational exposure to airborne fungi in two Croatian sawmills and atopy in exposed workers. Ann Agric Environ Med. 2012;19(2):213-219.
  2. Koschel D, Mailänder C, Schwab Sauerbeck I, Schreiber J. Non-allergic severe asthma: is it really always non-allergic? The IDENTIFY project. Allergy Asthma Clin Immunol. 2020;16(1):92. Published 2020 Nov 2. doi:10.1186/s13223-020-00489-z
  3. Forkel S, Beutner C, Schröder SS, et al. Sensitization against Fungi in Patients with Airway Allergies over 20 Years in Germany. Int Arch Allergy Immunol. 2021;182(6):515-523. doi:10.1159/000512230
  4. Benzrath S, Schlegtendal A, Brinkmann F, and Rettberg C. “Allergic Bronchopulmonary Mycosis Due to Rhizopus Nigricans in Two Siblings with and without Cf?”. European Respiratory Journal 48, no. suppl 60 (2016): PA1247. https://doi.org/10.1183/13993003.congress-2016.PA1247.

 

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