We would like to thank you for the letter titled “Differential diagnosis between pemphigoid and erosive lichen planus” about our recent paper and the opportunity to respond.

We carefully read the letter and think that the raised argument is very important. Pemphigoid is a disease in which the epithelium separates from the connective tissue due to autoantibodies attacking basal membrane components. When only the mucous membranes are affected, the term benign mucous membrane pemphigoid (BMMP) is often used. The main diagnostic feature of BMMP is separation of the epithelium from the connective tissue at the basal membrane region. Pemphigoid should be diagnosed based on clinical evidence with immunohistochemical investigation.¹ In a study of patients with the non-scarring phenotype of oral pemphigoid, circulating antibodies against the BP180 molecule were detected in 75% of cases.² In our study, pemphigoid was considered in the differential diagnosis of lichen planus. In the case whose pictures were shared, the Nikolsky sign was negative, an air bubble test was performed, and no bullae formation was observed. Biopsy material taken from the lesion area and healthy mucosa were sent to histopathological testing. With the direct immunofluorescence method, linear weak IgG (+) deposition was observed along the dermo-epidermal junction. Immune complex deposition with IgM (-), IgA (-), C3 (-) and fibrinogen (-) was not detected, and the diagnosis of benign mucosal pemphigoid was excluded.