Clinical, bacteriological, and dermoscopic study of pitted keratolysis

Background Pitted keratolysis is an acquired superficial infection of the skin. It is characterized by crateriform pitting of the pressure-bearing aspects of the plantar surface of the feet and occasionally in the palms of the hand as a collarette of scales. Objective To evaluate the role of a dermoscope in the diagnosis of pitted keratolysis and to correlate the dermoscopic diagnosis with bacterial diagnosis. Patients and methods The current cross-sectional study included 90 patients with pitted keratolysis. They were recruited from Outpatient Clinics of Dermatology and Venereology Department, Tanta University Hospitals. Clinical examination, bacteriological examination, and dermoscopic examination of the feet of the patients were performed. Results The clinical features of pitted keratolysis were still the gold standard for diagnosis. Crater-like pits by dermoscopic examination as well as Micrococcus sedentarius and Corynebacterium spp. were observed in patients with pitted keratolysis. The Corynebacterium spp. was more prone to develop a crater-like/punched out/ pigmented and crater-like/smooth/not pigmented pattern on desmoscopy, whereas the Micrococcus spp. was more prone to develop a crater-like/punched out/pigmented pattern on dermoscopy. There was no statistically significant relation between the dermoscopic criteria and bacteriological results. The dermoscope revealed 100% sensitivity in the diagnosis of pitted keratolysis, whereas the bacterial isolate was detected only from 90% of the clinically diagnosed cases of pitted keratolysis. Conclusion Dermoscopy is useful in the diagnosis of pitted keratolysis. Bacteriological examination helps to identify the type of organism in the lesion but does not confirm that the lesion in the foot is pitted keratolysis. The type of organism does not correlate with the dermoscopic criteria. Larger-scale studies correlating dermoscopic findings with bacteriological and histopathological results are recommended to improve the understanding of the dermoscopic criteria.