Superficial mycoses in patients with and without immune-mediated inflammatory diseases: a comparative mycological study

Introduction Superficial mycosis are infections caused by dermatophytes, yeasts, or other filamentous fungi that affect the skin and its appendages. They are the most common fungal infections and represent a global public health challenge. Predisposing factors include unfavorable microenvironmental conditions, advanced age, trauma, and immunosuppression. Immune-mediated inflammatory diseases (IMIDs) are characterized by shared inflammatory pathways and dysregulation of the immune system and are associated with the loss of immunological tolerance to self-antigens. Rheumatoid arthritis is the most common immune-mediated inflammatory disease, and the affected patients are particularly susceptible to infections of various etiologies because of the immunosuppression associated with both the disease and its treatment with anti-inflammatory and immunomodulatory drugs. The objective of this study was to compare the frequency of mycological confirmation, clinical presentation and etiological spectrum among patients with and without IMID. Methods The study included 82 consecutively recruited patients with lesions suggestive of superficial mycosis, classified into those with IMID (n = 51) who received treatment in the Rheumatology Department and those without IMID (n = 31) seen in the Dermatology Department, at a secondary-level hospital in Mexico City over a 19 months period. Skin and/or nail samples were collected from lesions for direct examination and culture. Fungal isolates were identified by morphological analysis and PCR-sequencing. Results Patients with rheumatoid arthritis predominated. In patients with IMID superficial mycosis was confirmed in 29/51 (56,8%) by microscopic examination and in 23/29 (79,3%) by culture. In patients without IMID superficial mycosis was confirmed in 15/31 (48,4%) patients based on a positive direct microscopic examination and in 9/15 (60%) patients by positive culture. The most frequently identified species was Trichophyton rubrum , followed by Candida spp. and Trichosporon spp. Several infection-associated species were mainly found in the group with IMIDs: 9/23 (39,1%). Conclusion This study expands possibilities for investigating various aspects of fungal infections and their causative agents in patients with IMIDs, with the participation of multidisciplinary specialist teams.