Pustular Psoriasis (cont.)

Exams and Tests

Your doctor may perform blood tests, including the following: 

• A complete blood count (CBC) will reveal lymphopenia (reduced lymphocytes, a type of white blood cell in the blood) with polymorphonuclear leukocytosis (a large number of another type of leukocyte) as high as 40,000 per microliter of blood.
  
  
• The erythrocyte sedimentation rate will be elevated. This means the rate of red blood cells that settle in anticoagulated blood is increased, indicating inflammation.
  
  
• Serum chemistry (breakdown of the levels of various components of your blood) will reveal increased plasma globulins (a type protein in the blood) and decreased albumin (a simple protein), calcium, and zinc. If you are oligemic (have a blood deficiency in your body), levels of blood urea nitrogen (BUN, a nonprotein nitrogen compound in the blood) and creatinine (a substance in your urine) are also increased.
  
  
• Blood culture is the process of placing blood in a culture medium and determining if any organisms in the blood grow.

Your doctor may take a urine sample. This will allow your doctor to assess creatinine levels (see above) and to determine if you have a kidney disorder. 

Your doctor may take a small sample of a pustule’s contents to perform a culture. The results from these cultures and blood cultures are usually negative (no sign of infection). A Tzanck test (test for altered skin cells) usually reveals no abnormalities. Viral cells also aren’t found. Since your skin is damaged, it may become infected, and the cultures are important.