Treatment of <i>Pseudomonas</i> Nail Infections with 0.1&percnt; Octenidine Dihydrochloride Solution

The beginning of the treatment was preceded by a 30-day washout period in subjects using topical or systemic antimicrobials. The patients were evaluated after 6 weeks of application of 0.1% octenidine dihydrochloride solution with microscopy and culture. Patients having both negative microscopy and culture results were considered as cured regardless of nail coloring, since the nail hue has been suggested to result from diffusion of pyocyanin rather than the true invasion of Pseudomonas in nail plate [1] . Ten patients reported that their hands were frequently immersed in water; the other 4 had diabetes or another nail disease and only 1 patient (No. 3) presented the Pseudomonas nail infection without any predisposing factors. At the end of the 6th week of application of 0.1% octenidine dihydrochloride solution, 12 of 15 patients (80%) had complete clearance of their affected nails ( fig. 2 ). Three female patients (No. 2, 11 and 14) failed to respond, probably due to their occupations. No adverse effects were noticed during the application period. Pseudomonas are gram-negative waterborne rod bacteria. The pathogenesis of nail infection by Pseudomonas remains obscure. It is considered to be a complication of onycholysis of various origin or chronic paronychia [2] , and this is confirmed in our series ( table 1 ). It also seems that a paronychial infection with Pseudomonas is usually preceded by onycholysis or paronychia, leading to pyocyanin pigment staining of the adjacent nail [1] . The disease commonly is restricted to 1 or 2 nails. Pseudomonas is usually isolated on cultures of specimens taken from the paronychia. Topical treatment includes removal of the onycholytic portion of the nail and avoidance of wetness [3] , brushing of the nail bed with a 2% sodium hypochlorite solution twice daily [1] , application of diluted acetic acid or polymyxin B 2 and vinegar soaks (10-parts water and 1-part white vinegar) for 5–10 min twice daily for 5 days [4] . Octenidine dihydrochloride is a well-known topical antibacterial agent active. Octenidine has been shown to possess microbicidal activity against Staphylococcus aureus , Staphylococcus epi