Permanent synthetic fillers have been widely used in esthetic procedures for body contouring. However, due to their irreversible nature and the high rate of associated complications, they represent a severe public health issue, especially in Latin American countries, where prevention campaigns are often ineffective. These substances, commonly known as biopolymers, trigger various immunological reactions after injection, predominantly a type IV hypersensitivity response similar to that observed in ASIA syndrome (Autoimmune Syndrome Induced by Adjuvants), although they are distinct clinical entities. This chapter aims to unify clinical and therapeutic criteria for patients with permanent synthetic fillers in the gluteal region, proposing a six-grade classification based on the complexity of symptoms. A therapeutic approach is also presented for each stage, aiming to establish a unified treatment protocol.