Clinical Implication of Hand-Held Black Light Findings and Their Correlation to Foot and Leg Wounds

Background: Interdigital bacterial and fungal infections, as well as chronic non-healing lower extremity wounds, both represent frequently encountered pathologies that a variety of health care practitioners treat on a regular basis. Previous studies have examined the clinical use of a Wood's lamp or a hand-held black light in a variety of bacterial and fungal cutaneous infections. Literature has reported that under ultraviolet (UV) light, Corynebacterium infections fluoresce coral-red, while pseudomonas infections will produce a green luminescence. This study also found that tinea capitus, a dermatophyte infection which is typically caused by Trichophyton or Microsporum, will fluoresce blue-green under Wood’s Lamp. However, clinical application of black light to identify common fluorescent bacteria or fungi and comparing interdigital specimen growth to adjacent foot and leg wounds is not commonly performed.

Results: Our preliminary findings suggest a possible connection between interdigital microorganisms and wound colonizing species. In the course of our examinations, we routinely illuminate patients using a hand-held black light source who present with interspace maceration. We extended the exam to include lower leg wounds, and foot wounds adjacent to macerated web spaces. In our examination approximately half of the data points (7/14) recorded demonstrated evidence of common interspace and wound species growth, while 29% (4/14) recorded negative correlation between the interspaces and the wound.

Conclusion: Our investigation demonstrated a slight predilection for foot wound contamination versus leg wounds. We also found wound and interspace colonization with similar species and a larger formal study may be indicated to determine the need for better interdigital hygiene and prophylactic treatment of interdigital web spaces.