Skin-nontumor / Clinical dermatology
Infectious disorders

Authors: Cecilia Rosales, M.D. and Mowafak Hamodat MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 20 May 2016, last major update July 2011

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Skin AND abscess [title]

Definition / General
  • Latin: abscessus
  • A skin abscess is a localized collection of pus that generally develops in response to infection or to the presence of other foreign materials under the skin; formed by tissue disintegration and surrounded by an inflamed area
  • Skin abscesses are often referred to as boils
  • Develops in patients of all age groups
  • Typically caused by either an inflammatory reaction to an infectious process (bacteria or parasite) or, less commonly, to a foreign substance within the body (a needle or a splinter, for example)
  • Abscesses may develop because of obstructed oil (sebaceous) or sweat glands, inflammation of hair follicles, or from minor breaks and punctures of the skin; abscesses may also develop after a surgical procedure
  • The most common bacterial organism is Staphylococcus aureus, although various other organisms can also lead to abscess formation
Clinical Features
  • An abscess is typically painful, and it appears as a swollen area that is warm to the touch
  • Hospitalizations for skin abscesses may be increasing (Eur J Clin Microbiol Infect Dis 2011;31:93)
  • The skin surrounding an abscess typically appears pink or red
  • Antibiotics alone will not typically cure a skin abscess
  • In general, abscesses must open and drain to improve
Micro Description
  • Cavity usually located on the dermis containing inflammatory infiltrate with abundant neutrophils and necrotic debris
  • The cavity is usually surrounded by inflammatory infiltrate
  • Usually also subepidermal edema
  • Extensive leukocytoclasis is seen in older lesions
Positive Stains
  • Gram positive or negative if bacterial origin