[Fillers and associated side effects]

A variety of fillers is commonly used for tissue augmentation as well as skin rejuvenation, and consist of a large heterogeneous group of biomaterials. The objective was to provide an overview and classification of the most commonly injected filler materials and filler-related complications including therapy.

A summary of the current literature and common associated side effects is provided from a personal clinical perspective.

According to degradability, filler materials can be classified as temporary (degradable), semi-permanent, and permanent (nondegradable). Temporary fillers such as hyaluronic acid and collagen are completely degraded by the surrounding tissue within several months. Semi-permanent fillers are degradable, but may induce longer-lasting secondary effects. Permanent fillers such as silicone and mineral oil derivatives are not biodegradable and have been increasingly abandoned because of severe and irreversible side effects. The most common filler-related adverse events include pigmentation changes, edema and post-injection deformations. Visible or palpable nodules can be due to filler accumulation, formation of granuloma, or infection.

Substantial knowledge of the chemical and clinical features of the injected materials is indispensable for safe and efficient application. Early recognition of filler-related adverse effects is important to avoid severe complications and to achieve optimal results.