A rare skin disease characterized by chronic eruption of sterile pustules on an erythematous and desquamative background, affecting the palms and soles, sometimes also the lateral aspects of hands and feet. The lesions are usually painful. Nail lesions (such as nail pitting, onycholysis, subungual pustules, and nail dystrophy) are also observed. The condition takes a chronic and relapsing course. Typical associations are psoriatic arthritis, thyroid gland dysfunction, and smoking.