To Evaluate the Pharmacokinetic of Diacerein and Rhein After Maximum Use in Patients With Epidermolysis Bullosa (EB)

Key Inclusion Criteria: * At least 12 years of age (Cohort 1) or at least 6 months of age to 11 years, inclusive (Cohort 2) at screening. For US only: at least 4 years of age to 11 years, inclusive (Cohort 2) * The subject must weigh at least 9 kg (19.8 lbs) at Screening. * Subject has a documented genetic mutation consistent with EB. * Subject has EB lesions on ≥ 2% body surface area (BSA) and the EB lesions are in the following body areas: a. Localized: plantar and/or palmar areas, b. Generalized: arms, legs, torso, hands and feet. Key Exclusion Criteria: * Subject has EB lesions where drug will be applied that are infected * Subject has used any diacerein containing product within 1 month prior to Visit 1 * Subject has used systemic immunotherapy or cytotoxic chemotherapy within 60 days prior to dosing. * Subject has used systemic steroidal therapy or has used topical steroidal therapy on the EB lesions in the application area within 14 days prior to dosing * Subject has participated in an investigational drug trial in which administration of an investigational study medication occurred within 30 days prior to dosing