Neither the etiology nor a reliable treatment for palmoplantar pustulosis has been clearly established. Ozone nanobubble (ONB) water, which is treated with nanosized ozone gas particles and has strong antimicrobial activity, has attracted attention as a future therapeutic option for palmoplantar pustulosis. Oral rinsing, particularly in the periodontal areas, with 10 to 20 mL ONB water for a couple of minutes per night, was prescribed to seven palmoplantar pustulosis patients, comprising five female and two male patients, for 6 months. Skin lesions were observed to be completely cured within a treatment period of approximately 3 to 4 months in six patients; the exception
case was the one suspected of having pyorrhea. Rinsing the periodontal area with ONB water resulted in very effective suppression of skin lesions and showed promise as a new treatment method for palmoplantar pustulosis, which suggested the involvement of oral bacteria.