Efficacy of Guselkumab in Treating Hailey Hailey Disease

Inclusion Criteria: * A documented diagnosis of Hailey-Hailey disease confirmed with clinical, and histopathologic findings * Disease affecting more than one body site with at least moderate severity * If patients are taking other systemic therapies for their HHD (antibiotics, prednisone), they must be taking a stable dose of the other medication(s) for at least 3 months with no plans to change the regimen in the next 6 months. With the exception of antibiotics, methotrexate or low dose prednisone (less than 5 mg daily), use of concomitant immunosuppressants, e.g. azathioprine, etc. and biologics other than TNF-α inhibitors will not be permitted. * Patients must be willing to have skin biopsies, blood collection, and total body photography and to comply with clinic visits Exclusion Criteria: * Patients with a history of malignancy (except history of successfully treated basal cell or squamous cell carcinoma of the skin over six months prior to first study drug administration). * Patients known to be HIV or hepatitis B or C positive. * Patients planning to receive live vaccines during the duration of the study. * Patients with a positive tuberculin skin test or positive QuantiFERON TB test. * Patients with significant hepatic impairment (Child-Pugh class B and C). * Patients taking immunosuppressive and biologic medications, except for methotrexate, low-dose prednisone, and TNF-α inhibitors, including but not limited to mycophenolate mofetil, azathioprine, tacrolimus, and c…