The histo-pathological lesions of
hypersensitivity vasculitis (HV) consist in an inflammatory reaction to circulating
immune complexes deposited on the vascular endothelium. A provocation test by
intradermal injection of
histamine was used to demonstrate HV in patients with
chronic hepatitis. Three groups of patients were studied: 16 with
chronic hepatitis and HV, 22 with
chronic hepatitis without HV, 4 control subjects. Skin biopsy was performed before and 3 hours after intradermal
histamine. The following markers were looked for in the serum, skin and liver of all patients with
chronic hepatitis: HBV (HBs Ag and HBe Ag, anti-HBs, anti-HBe and anti-HBc in the serum, HBs and HBc Ag in the liver); non-A non-B (non-A, non-B Ag and antibody, anti non-A non-Bc in the serum, non-A, non-Bc Ag in the liver).
Viral antigens were found in healthy skin in 2 cases (1 chronic A
hepatitis, 1
vasculitis), and after injection of
histamine in 9 cases (4 chronic A
hepatitis, 5
vasculitis).
Viral antigens were found on skin biopsy in 2 patients with negative sera. Significant skin changes after
histamine were detected only in HV (75 p. 100) even in the absence of
cutaneous vasculitis (6/12 positive cases). An intradermal
histamine provocation test is a simple, non-invasive method for diagnosing HV.