Vasculitis as the basis of cutaneous lesions in Reiter's disease

The cutaneous lesions of Reiter's disease (RD) and pustular psoriasis (PP) are said to be histologically similar and often indistinguishable. We encountered three cases of RD in which biopsy specimens of lesions clinically compatible with keratoderma blenorrhagicum showed a pustular psoriasiform tissue reaction in conjunction with a subjacent superficial leukocytoclastic vasculitis (LCV). In an attempt to ascertain if these changes were distinctive and unique to cutaneous RD, the incidence of such changes in lesions of PP was examined using light microscopy and immunohistochemistry. The role of chlamydial infection in the pathogenesis of the observed vascular changes also was explored by assessing for the presence or absence of vascular deposition of chlamydial antigen in cutaneous RD compared with that in a control group that included cases of LCV and PP. In addition to conventional light microscopic analysis, immunoperoxidase studies to identify immunoglobulin deposition were performed on formalin-fixed, paraffin-embedded tissue from two of three patients with RD and on skin biopsy specimens from 11 patients with PP. Direct immunofluorescence (DIF) studies with antibodies to immunoglobulin (Ig)G, IgM, IgA, C3, and chlamydial antigens were performed on frozen tissue from one patient with RD, two patients with PP, three patients with LCV, one patient with nonspecific dermatitis, and one patient with Behçet's disease, who had a high antichlamydia antibody titer. All three specimens of RD showed a pustular psoriasiform diathesis in conjunction with a subjacent superficial LCV that was of maximal intensity in the dermal papillae capillaries. Through an immunoperoxidase technique performed on formalin-fixed tissue, the RD cases for which tissue was available for study demonstrated Ig deposition in injured blood vessels; using the same technique one of 11 PP biopsy specimens showed vascular Ig deposition in concert with LCV. This patient's biopsy was from a lesion of drug-induced LCV. None of the other specimens showed either light microscopic or immunohistochemical evidence of vasculitis. In the one specimen of RD studied by DIF, vascular deposition of IgG, IgM, C3, chlamydia heat shock protein 60 (CHSP60), and chlamydia-specific lipopolysaccharide (LPS) was observed. In the two specimens of PP studied, vascular deposition of C3, fibrin, CHSP 60, and chlamydia-specific LPS was not observed. Two specimens of LCV and the one specimen of dermatitis with concomitant nonspecific vascular injury showed vascular Ig and C3 deposition; in contrast, no vascular deposition of CHSP 60 or chlamydia-specific LPS was observed.(ABSTRACT TRUNCATED AT 400 WORDS)