infectious diseases
Herpes Zoster
Diagnosis of Herpes Zoster
History and physical examination Herpes zoster is suspected in patients with the characteristic rash and sometimes even before the rash appears if patients have typical pain in a dermatomal distribution. Diagnosis is usually based on the virtually pathognomonic rash. If the diagnosis is equivocal, detecting multinucleate giant cells with a Tzanck test can confirm infection, but the Tzanck test is positive with herpes zoster or Herpes Simplex Virus (HSV) Infections . Herpes simplex virus (HSV) may cause nearly identical lesions, but unlike herpes zoster, HSV tends to recur and is not dermatomal. Viruses can be differentiated by culture or polymerase chain reaction (PCR). Antigen detection from a biopsy sample can also be used to detect herpes zoster. 