Cellulite is defined as a localized metabolic disorder of subcutaneous tissue.

The main clinical symptom is a modification of the topography of the skin characterized by skin dimpling and nodularity. Diagnosis is based on the clinical features of the disease. At the microscopic level, cellulite presents with herniation of subcutaneous fat with fibrous connective tissue, leading to an orange peel-like or padded appearance of the skin.

The condition occurs mainly in postpubertal women on the pelvic region, lower limbs and the abdomen, and is divided in four stages.
The first stage affects the microcirculation of the skin, with no superficial changes observed.
During the second stage (secretion stage) the vasodilation is converted into the release of liquids to the extracellular space, and the skin starts to develop an orange peel-like texture.
The third stage (fibrosing stage) is characterized by an increase in number and size of adipose cells which form micronodules (cluster). The hypodermal septa thicken and become turgid. The spongy appearance of the skin becomes obvious in a lying position.
The fourth stage (sclerosis stage) can be seen as aggravation of the fibrosing stage, with the hypodermal septa becoming harder and further thickening. The irregularities, depressions and protrusions of the skin are visible to the naked eye.

Various treatments for cellulite have been developed, such as (in order of decreasing evidence-based medicine [EbM] level*): laser-assisted lipolysis (EbM level I-A), topical phosphatidylcholine and LED (I-A), endermology (II-A), radiofrequency (II-A), topical herbs and retinol (II-A), ultrasound (II-A), carboxy therapy (II-B), mesotherapy (II-B), weight loss (II-B), liposuction (III), cryolipolysis (IV), and subcision (IV). Radial shock wave therapy (RSWT) has been demonstrated being efficient for cellulite stages II and III (EbM level IIB), with improvement by approximately one stage for several months.

*Level IA: evidence from metaanalysis of randomized controlled trials.
Level IB: evidence from at least one randomized controlled trial.
Level IIA: evidence from at least one controlled study without randomization.
Level IIB: evidence from at least one other type of experimental study.
Level III: evidence from nonexperimental descriptive studies, such as comparative studies, correlation studies, and case control studies
Level IV: evidence from expert committee reports or opinions or clinical experience of respected authorities, or both.