Impetigo (see Impetigo): infection of superficial layers of the epidermis
Cellulitis (see Cellulitis): skin infection of deeper dermis and subcutaneous fat (resulting from bacterial breach of the skin) characterized by erythema, warmth, and edema without an underlying suppurative focus
Erysipelas (see Erysipelas): skin infection of upper dermis and superficial lymphatics (resulting from bacterial breach of the skin) characterized by erythema, warmth, and edema without an underlying suppurative focus
Furuncle (Boil) (see Skin Abscess): infection of hair follicle where purulent material extends through the dermis into the subcutaneous tissue, forming a small abscess
Carbuncle (see Skin Abscess): coalescence of several inflamed follicles into a single inflammatory mass with purulent drainage from multiple follicles
Skin Abscess (see Skin Abscess): collection of pus within dermis and deeper skin tissues
Necrotizing Soft Tissue Infection (see Necrotizing Soft Tissue Infection): deep tissue infection involving the hypodermis (and contained structures)
All of These are Characterized by Fulminant Tissue Destruction, Systemic Toxicity (Tachycardia >120 Beats/min, Hypotension, Elevated Creatine Kinase, CRP >15 mg/dL, LRINEC Score >6, etc), and High Mortality Rates
Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59(2):e10-52. doi: 10.1093/cid/ciu444 [MEDLINE]