Investigation of causative agents of intertrigo with direct smear, Wood light and culture methods

Diagnosis of intertrigo and related secondary infections is usually made by clinically. Some laboratory methods has been used to confirm clinical diagnosis or determine secondary infections. Direct smear with potassium hydroxide (KOH) for secondary fungal infections and Wood light for erythrasma or pseudomonal infections may roughly give us an idea. Also biopsy or culture methods have been applied for the conditions unresponsive to the therapy or cronic inflammation which requires differential diagnosis. Direct smear with KOH and Wood light examinations are important diagnostic tools that may be preferred in the first step health service. They are appliable easly, quick, reproducible, requiring no special equipment and non expensive methods. In our study, we mainly aimed to determine and accurately diagnose the most frequent causative agents of intertrigo with simple techniques without applying expensive, time consuming, and experience requiring investigation methods.In a total of 115 patients (67 male and 48 female) with intertrigo, proper samples were obtained from the lesional regions for direct smear, gram stain, bacterial and fungal cultures. Lesion areas were also examined with Wood light. On direct KOH examination, 29.6% septate hyphae related to dermatophytes and 25.2% pseudohyphae related to monilia were observed whereas, 20% red, 7.8% green, and 3.4% yellow flourosence were observed under Wood light examination. Results were confirmed with fungal culture in 56% of patients with dermatophytic and 66% of candidal intertrigo. Results were also confirmed with bacterial culture in 35% of patients with erythrasma and 89% of patients with pseudomonal intertrigo. The most common isolated agents were 22% candida, 21% dermatophyte, 13% Pseudomonas aeruginosa (PA), 11% gram (-) bacteria such as Proteus mirabilis, Klebsiella pneumoniae, and 10% E.coli, 10% gram (+) bacteria such as Staphylococcus aureus, and 7% corynebacteria, respectively. Namely, intertrigo were infected frequently with candida, dermatophytes, pseudomonas, other gram (-) bacteria, gram (+) cocci and corynebacteria. Mixed infections were observed in 23% of patients. Although the most common predisposing factors were hyperhidrosis, obesity, and diabetes, in 33% of patients were encountered without any predisposing factor.The most frequently seen clinical type was toe-web intertrigo. In this group, 29% trichophyton, 16% PA, 11.7% other gram (-) bacteria, 10.5% candida, and 9.3% corynebacteria were isolated on the culture, respectively. Namely, toe-web intertrigo was frequently infected with dermatophyte, pseudomonas, other gram (-) agents, candida, and corynebacteria. In 17% of these patients, there was a mixed infection with bacterial and fungal agents, however in 1.3% of them, there was a bacterial or fungal mixed infection composed of double agents. In 8% of interdigital intertrigo, concurrent erysipelas or cellulitis were also detected. Toe webs were most frequently infected with dermatophytes and the main pathogens were Trichophyton rubrum and Trichophyton mentagraphytes, respectively. Gram (-) bacteria were isolated in 28% of patients who has toe-web intertrigo. PA was responsible from 57.1% of this condition. The most important predisposing factors are hyperhidrosis, occlusion, diabetes mellitus, obesity, excessive washing of foot due to ablution. In 43% of patients, different topical treatments have been used previously. In 22 patients with interdigital erythrasma by Wood evaluation, corynebacteria were isolated only from 9.3% of them.The secondly frequent clinical type was submammary intertrigo. This condition was detected in 21% of female patients and 40% of these were infected with candida.If fungal and bacterial culture are considered gold standarts; correlations between direct smear and fungal culture for dermatophytic and candidal intertrigo, Wood light and bacterial culture for erythrasma or pseudomonal intertrigo were statistically significant. Sensitivity and specifity of direct smear with KOH for dermatophytic intertrigo were stated as 79% and 84%, and 83% and 89% for candidal intertrigo, respectively. Sensitivity and specifity of Wood light were 100% and 86% for erythrasma, and 89% and 87% for pseudomonal intertrigo, respectively.In conclusion; direct smear with KOH and Wood light are highly sensitive and specific, easy, practical, reliable, and suitable diagnostic methods in the diagnosis of intertrigo and related secondary infections. With these methods, about 61.5% of secondary infections can be diagnosed and treated without applying the methods that are expensive, experience requiring, and time consuming. According to our results, these two simple methods are ideal screening tests which should be used in determining the types of intertrigo.