Cellulitis is a frequent pathology in both outpatient and inpatient clinical practice. This article reviews the pathophysiology of cellulitis, as well as the various complementary examinations useful in its diagnosis. It describes current recommendations for its management. Several differential diagnoses may also be considered, such as stasis dermatitis, lymphedema or deep vein thrombosis. These must be distinguished from cellulitis to avoid unnecessary antibiotic therapy. There are also a number of specific cases of cellulitis (necrotizing fasciitis, bites, diabetic foot) requiring special management. These are also discussed in this article.