Analysis and evaluation of correlation for clinical, dermoscopic and histological signs of rare inverse localized paradoxal psoriasis: case report – 2 similar cases

TNFα inhibitors are widely used and highly effective in the treatment in number of chronic inflammatory diseases, including psoriasis. Although TNFα inhibitors block multiple pathways responsible for psoriasis, in 2% of cases they cause eruption of rash characteristic for this disease-specific rash known as paradoxial psoriasis. Aim of  our report is identification and analysis for phenomenon of paradoxal psoriasis in patients treated with TNFα inhibitors. In our report we describe 2 patients, women 16 and 42 years of age with inverse localization of psoriasis, which started pin less than a year after treatment for Chrohn`s disease with TNFα inhibitors was initiated Unlike in our report , the paradoxal forms of psoriasis usually described in literature reviews include pustulosis of the palms of the soles ,scalp psoriasis, as well as vulgare and guttate forms of psoriasis. The diagnosis of psoriasis for patients described  in our case report  was confirmed pathohistologicaly. Both patients had psoriasis-related comorbidities, respectively, Chrohn `s disease and spondylitis, why they received treatment of TNFα inhibitors. Reason of paradoxical psoriasis is delayed maturation of plasmacytic dedritic cells (pDC) due to abundant blocking of TNFα signaling, finally resulting in exaggerated IFNα response. Pathohistological examinations of the epidermis revealed the typical signs of psoriasis - parakeratosis, agranulosis and mitosis in the basal layer. However, although purulent exudative crusty  scales were observed in both patients, neutrophils so characteristic for psoriasis were not detected in the dermis. And also tortured capillaries typical for psoriasis were not observed in both the histological and dermascopic patterns. Although our described clinical manifestations induced by TNFα inhibitors were consistent with of psoriasis, discrepancies were found in the histopathological and dermasacopic patterns, indicating the distinct mechanisms of pathogenesis for classical and paradoxal psoriasis.