Atypical Presentation of Stenotrophomonas maltophilia Stomatitis Post COVID-19 in an Immunocompetent Adolescent

<i>Stenotrophomonas maltophilia</i> (S. <i>maltophilia</i>) is a rare, multi-drug-resistant opportunistic bacteria that typically causes serious infections in immunocompromised and hospitalized patients, often leading to fatal pneumonia or bacteremia. We present the case of a healthy 15-year-old immunocompetent female who developed severe oral ulcers due to <i>S. maltophilia</i> following a recent COVID-19 infection. To our knowledge, this is the first reported case of <i>S. maltophilia </i>manifesting in this manner after COVID-19. Scrapes from the oral lesions were collected and cultured, confirming the<i> </i>infection.The CBC and immunoglobulin reports revealed mildly elevated IgA and platelet levels, with no evidence of immunodeficiency.The patient was treated with trimethoprim/sulfamethoxazole (TMP-SMX) based on culture sensitivity, and she responded well to treatment. She was referred to an infectious disease specialist for further monitoring. COVID-19 has recently been implicated in many unusual presentations, associations, and syndromes. One of the most supported theories about COVID-19 is its association with a transient immunodeficient state or a generalized state of immune system dysregulation that can compromise both innate and adaptive immunity. This case supports that theory, as no other apparent etiology for such an otherwise opportunistic infection was identified. The recognition of such atypical infections in previously healthy individuals, particularly post COVID-19, highlights the importance of sharpening clinical vigilance and considering opportunistic pathogens in differential diagnoses. Further research is warranted to explore the potential link between COVID-19 and the susceptibility to rare opportunistic infections, which may guide future clinical practices.