Case Report: Primary Cutaneous Histoplasmosis in an Immunocompetent Patient After Cosmetic Injection of Platelet-Rich Plasma Treated with Trimethoprim-Sulfamethoxazole

Abstract

BACKGROUND Histoplasmosis is typically associated with immunocompromised individuals, but cases in immunocompetent patients are rare. Primary cutaneous histoplasmosis (PCH) is a challenging diagnosis due to its clinical polymorphism and can mimic other infectious and non-infectious diseases. Previous cases of PCH have been reported in immunocompetent patients with underlying medical conditions or trauma history. So far there have been no reports of PCH after platelet-rich plasma (PRP) application due to inadequate hygiene measures in an immunocompetent host. CASE REPORT This case report presents a rare occurrence of PCH following a cosmetic procedure (PRP injection) in an immunocompetent patient. The patient developed nodule-like lesions at the application sites, which progressed to ulceration with purulent discharge. Initially, atypical mycobacterial infection was suspected, and empirical antibiotic therapy was initiated. Complementary tests were performed, ruling out immunosuppression and systemic pathogens. The patient showed complete resolution of the lesions after one month of atypical treatment with trimethoprim-sulfamethoxazole (TMP/SMX). Pathological examination confirmed the diagnosis of PCH with intracytoplasmic inclusions of Histoplasma sp. CONCLUSIONS This case highlights the importance of considering histoplasmosis as a diagnostic possibility, especially in hyperendemic areas like Venezuela. Direct inoculation of Histoplasma sp. after aesthetic procedures without proper hygiene measures can lead to pathological lesions, even in immunocompetent individuals. TMP/SMX can be considered as an alternative treatment option in the absence of the first-line medication. Further exploration of this treatment approach may benefit patients with similar clinical conditions or when ideal treatment options are unavailable.

Figure 1.

(A, B) Erythematous nodules in the frontal and right zygomatic areas. (C) Plaque-like lesion in the left buttock with central ulceration and purulent material discharge. (D) Erythematous indurated plaques on both buttocks.

Figure 2.

(A) Nodule resolution in the frontal and zygomatic areas with visible residual hyperpigmented area. (B) Plaque resolution in the buttocks, with scarring and residual hyperpigmentation in previously affected areas.

Figure 3.

(A, B) In the dermis, hematoxylin and eosin (H&E) staining reveals dense infiltration of histiocytes, epitheloid cells and multinucleated Langhans giant cells. (B) Numerous intracellular yeast-like structures (blue arrows) with ovoid shape and a peripheral halo suggestive of Histoplasma capsulatum are visible.