dermatologic disorders
Bullous Pemphigoid
Etiology of Bullous Pemphigoid
No cause of bullous pemphigoid has been proved; however, the following triggers have been suggested: Drugs (includingfurosemide,spironolactone,omeprazole, PD-1 and PD-L1 monoclonal antibodies [eg,durvalumab,nivolumab,pembrolizumab],sulfasalazine, penicillin,penicillamine,etanercept, antipsychotics, and dipeptidyl peptidase-4 inhibitors) Physical triggers (including trauma, radiation therapy for breast cancer, UV radiation, andanthralin) Skin disorders (including Psoriasis , Disorders ( Diabetes Mellitus (DM) , Genetic and environmental factors may play a role. Triggers may induce an autoimmune reaction by mimicking molecular sequences in the epidermal basement membrane (molecular mimicry, as with drugs and possibly infections), by exposing or altering normally tolerated host antigens (as with physical triggers and certain disorders), or by other mechanisms. Epitope spreading refers to the recruitment of autoreactive lymphocytes against normally tolerated host antigens, which contributes to disease chronicity and course. Certain central nervous system (CNS) and psychiatric disorders may precede bullous pemphigoid, especially multiple sclerosis and schizophrenia, but also dementias, intracranial bleeds, stroke, delusional and personality disorders, and Parkinson disease. To a lesser degree, these disorders may be preceded by bullous pemphigoid. Hypothesized shared causes include a cross-reactive immune response between neural and cutaneous antigens (BPAg1 is expressed in the CNS), as well as triggering by certain drugs used to treat the disorders (eg, phenothiazine antipsychotics,spironolactone); however, a mechanism of triggering by drugs is not understood. 