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 cyclosporine. * Are pregnant, nursing, or planning a pregnancy while enrolled in the study or for 12 weeks after the study agent injection for women or are planning to father a child while enrolled in the study or for 12 weeks after the last study agent injection. * Prior biologic use within the last 3 months. * Participant has known allergies, hypersensitivity, or intolerance to guselkumab or its excipients (refer to Investigator's brochure) * Presence of significant uncontrolled respiratory, hepatic, renal, endocrine, hematologic, neurologic, or neuropsychiatric disorders, or abnormal laboratory screening values that, in the opinion of the investigator, pose an unacceptable risk to the subject if participating in the study or of interfering with the interpretation of the data. * Active, untreated, acute infection, or immunocompromised to an extent that participation in the study would pose an unacceptable risk to the subject based on the investigator's clinical assessment. * Symptomatic herpes zoster infection within 12 weeks of screening or recurrent or disseminated (even a single episode) herpes zoster. * Symptomatic herpes simplex or disseminated (even a single episode) herpes simplex at the Week 0 (baseline) visit. * Patients with the potential for keloid formation, e.g. patients with a propensity for keloid formation, defined as a personal history of 3 or more keloids.