Metal allergy and palmoplantar pustulosis

There is controversy surrounding the existence of palmoplantar pustulosis (PPP) and psoriasis as separate clinical entities, or as variants of the same clinical entity. PPP is usually defined as a chronic skin disease characterized by crops of sterile pustules with erythema and sometimes scaling on the palms and soles. PPP has in some studies been associated with autoimmune conditions such as thyroid diseases and celiac disease. Positive patch test reactions to several metals have been documented in patients with PPP, and notably, removal of dental alloys with these metals has been reported in some cases to result in the resolution of skin manifestations, suggesting a causative relationship. PPP is associated with moderate-to-severe discomfort and disability and is difficult to treat, often requiring the use of immunosuppressive agents.