Onset

• The onset of arthritis associated with psoriasis usually happens during middle age. The skin condition precedes the arthritis in almost 80 percent of patients, according to the NPF.
  
  

Affected Joints

• Psoriatic arthritis symptoms usually affect the person's knees, ankles and joints in the feet, which can become painful, stiff and swollen.
  
  

Localized Inflammation

• In addition, tendon and cartilage inflammation may occur in this disorder.
  
  

Additional Inflammation

• Psoriatic arthritis also can create inflammation in other body tissues and organ systems such as the eyes, lungs, heart and kidneys.
  
  

Acne and Nail Conditions

• Acne can occur as well, along with changes to finger and toe nails involving pitting and ridges.