Nail discoloration caused by topical treatment with luliconazole 5% nail solution (Luconac® Solution 5%) was investigated in vitro using human nail, and clinical management of the condition is discussed. A white discoloration was observed on nails after repeated topical application of luliconazole 5% nail solution. The discoloration was removed by scrubbing with either body soap or 70% ethanol solution, suggesting that it was due to precipitation of the active ingredient (luliconazole) on the nail surface. Maintaining the nail in an artificial environment illuminated with white fluorescent light at 10,000 lux caused the white discoloration to turn yellowish and become more difficult to remove, possibly as a result of photodegradation of luliconazole both on the nail surface and within the nail plate. In conclusion, superficial discoloration of the nail surface resulting from luliconazole application can be removed by scrubbing with either body soap or 70% ethanol solution. Avoiding light exposure of treated nails is recommended to prevent deeper discoloration that is more difficult to remove.