Diagnostic Testing

Diagnosis of all bullous conditions is based on three measures:

  • Clinical features – appearance of lesions, erosions and blisters, Nikolsky sign, presence or absence of scarring and distribution of lesions
  • Biopsy of skin or mucous membrane, with characteristic histological features
  • Direct and indirect immunofluorescence – detection of autoantibodies either in a biopsy specimen (direct) or in the patient’s serum (indirect). Indirect (circulating) antibodies are helpful in confirming the diagnosis. The enzyme-linked immunoabsorbent assay (ELISA) is helpful for diagnosis, particularly if the immunofluorescence studies are negative, and to differentiate PV from PF; in the future newer more specific ELISAs hold promise as a prognostic indicator.

The following investigations are also recommended during disease assessment and management

  • Full blood count and differential,
  • Blood urea and electrolytes,
  • Liver function tests,
  • Blood glucose,
  • Antinuclear antibody (differential of pemphigus erythematosus),
  • Thiopurine methyltransferase (TPMT) levels (if azathioprine is to be used),
  • Chest X-ray
  • Urinalysis
  • Blood pressure.
  • Bone density scan (early in the course of treatment is recommended, and repeated periodically)
  • PPD
  • G6PD and reticulocytes if dapsone is to be used.
  • Opthalmologic exam