An infective aetiology for vulval lichen sclerosus re-addressed

Although there is evidence to support an autoimmune basis for lichen sclero sus, there have also been some studies which suggest an infective aetiology . These include reports of the presence of spirochaetal forms with Steiner silver stains and purplish coccoid forms with Fite stains. We have repeated these studies on vulval biopsies obtained from 16 patients with vulval lic hen sclerosus. Using the Steiner silver method we found no evidence of spir ochaetal forms in any of the specimens. With the Fite stain we observed pur ple-staining coccoid forms within the dermis of 13 of the 16 lichen scleros us specimens. However, these coccoid forms also stained strongly positive w ith toluidine blue, suggesting they were mast cell granules rather than mic ro-organisms. We were therefore unable to demonstrate evidence for an infec tive aetiology in vulval lichen sclerosus, although this cannot yet be excl uded. Further work is also needed to understand the significance of mast ce lls in lichen sclerosus.