Systematic Review of Tinea Nigra: A Clinical Approach

Tinea nigra (TN) is a superficial fungal infection caused by the melanized fungus Hortaea werneckii, characterized by irregular dark patches, typically on the palms. This systematic review aims to evaluate the epidemiology, demographic characteristics, lesion distribution, diagnostic approaches, causative agents, and treatment outcomes of TN. The PubMed and MEDLINE databases were systematically searched using relevant keywords from January 1990 to January 2025, yielding a total of 102 cases across 42 studies. TN is more prevalent in tropical regions, with a higher incidence in the Americas (64 cases), particularly Mexico (23 cases), Brazil (17 cases), and Cuba (8 cases). The infection is more commonly observed in females (58 cases) than males (44 cases), with a mean patient age of 16.7 years (SD ± 13.58). The most frequently affected anatomical site is the palm, with 41 cases on the left palm, 34 on the right, and 5 involving both palms. Other affected sites include the soles and interdigital areas. Diagnosis typically involves direct microscopic examination using potassium hydroxide (KOH) preparation, which was performed in all cases, while cultures were conducted in 96 cases and dermoscopy was used in 14 cases. Hortaea werneckii was the predominant species isolated (74 cases), followed by Exophiala werneckii (14 cases), Pullularia werneckii (4 cases), and Aureobasidium melanogenum (3 cases). Recently, a new etiologic agent, Cyphellophora ludoviensis, was reported, among others. Over 25 treatment modalities were reported, with topical therapies being the most common. Whitfield's ointment was used in 12 cases, followed by ketoconazole 2% cream (11 cases), and terbinafine 1% cream and isoconazole 1% cream (10 cases each). Spontaneous resolution occurred in two cases. The average treatment duration across all modalities was 4 weeks, with a 100% resolution rate. This systematic review emphasizes the importance of understanding TN's clinical presentation, diagnostic techniques, and therapeutic strategies to optimize patient care and guide future research on this relatively uncommon fungal infection.