Improvement of Psoriasis Using Oral Probiotic Streptococcus salivarius K-12: a Case–Control 24-Month Longitudinal Study

Psoriasis is a common chronic skin disease, associated with an important physical and physiological involvement for any age. There is a strong link between psoriasis and streptococcal infection, particularly that of the tonsils. There are many therapies to treat psoriasis including topical, systemic, and biologic agents but these treatments are not free from side effects. Streptococcus salivarius K-12 is an oral probiotic product useful for the prophylaxis and treatment of tonsillar infections in children and adults, now tested here for the first time for control of psoriasis. Our retrospective analysis was conducted on 198 patients affected by mild to moderate psoriasis: 100 patients were first treated for 90 days with Streptococcus salivarius K-12, while 98 did not receive any probiotics and were the control group. The patients treated with S. salivarius K-12 exhibited a significant improvement of their psoriasis from the baseline condition: 83.7% patients treated achieved a 100% improvement of the PASI score at 24 weeks and efficacy continued to improve with longer treatment, maintaining same result also during follow-up observation. In all patients, the treatment was well tolerated, and no adverse events have been observed. Our data show that oral preparations containing Streptococcus salivarius may provide a beneficial option for the prevention and cure of pediatric and adult psoriasis.