[Satellite vasculitis of B or non-A non-B hepatitis. Diagnostic value of a provocation test by intradermal injection of histamine].

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.