Cold atmospheric plasma sources are emerging as new potent tools in different fields of medicine, from oncology to dermatology. Psoriasis is a chronic inflammatory disease characterized by the presence of itchy red plaque on skin, known as psoriatic plaques. In this case report, we evaluate the effectiveness of a cold atmospheric plasma treatment on a psoriatic plaque on the hand of a 20-year-old woman. Two quick applications of the procedure led to a complete disappearance of the cutaneous lesion in 14 days. The results of this case show a potential application of this new technique in the dermatological field, as palmo-plantar psoriasis is usually resistant to traditional treatments. A clinical trial would be necessary in order to evaluate the real effectiveness of this plasma.