Palmoplantar pustulosis and pustulotic arthro‐osteitis treatment with potassium iodide and tetracycline, a novel remedy with an old drug: a review of 25 patients

Background The use of potassium iodide ( KI ) to treat palmoplantar pustulosis ( PPP ) and pustulotic arthro‐osteitis ( PAO ) has not previously been reported. Here, we report the first successful treatment of PPP and PAO with KI . Patient and Methods Among 25 patients with PPP , seven had an associated PAO . All patients were administered 900 mg KI three times per day for 3 months. Overall, 12 patients received this medical treatment for the first time or had >6 months interval since the last therapy for PPP . The other 13 patients who were nonresponsive to tetracycline for >3 months prior to KI treatment were treated with a combination of KI and tetracycline. All seven patients with PAO were included in the tetracycline and KI ‐treated group. Results More than 70% of patients demonstrated complete clearance or ≥50% improvement in palmoplantar pustular psoriasis area and severity index ( PPPASI ) from baseline. In the group with <50% improvement in PPPASI from baseline, all except one patient were smokers. In the KI with tetracycline treatment group, approximately 80% demonstrated improvement. At the end of 3 months, there was remission of arthralgia in five out of seven PPP patients with PAO . Conclusions Treatment with KI and/or its combination with tetracycline may be a useful treatment for PPP / PAO . Smoking may affect the effectiveness of these treatment modalities.