Skin-nontumor / Clinical dermatology
Other dermatoses
Acne vulgaris

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

Revised: 17 June 2016, last major update July 2011

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

PubMed Search: Acne vulgaris [title] skin

Cite this page: Acne vulgaris. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumoracne.html. Accessed December 8th, 2016.
Definition / General
  • Common skin disease of seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), nodules (large papules) and possibly scarring
  • Typically affects skin with densest sebaceous follicles: face, upper chest, back; uncommon in scalp for unknown reasons
Terminology
  • Acne vulgaris is common acne, typically with comedones
  • Acne rosacea is a different disorder
Etiology
  • Due to hormonal variations and alterations in hair follicle maturation
  • Begins with abnormal follicular keratinization with retention of keratinous material in the follicle
  • Then increased sebum production
  • Then appearance of gram-positive, anaerobic, diphtheroid Propionibacterium acnes
  • May become inflammatory
Diagrams / Tables

Images hosted on other servers:

Stages of acne

Clinical Features
  • Usually teenagers of either sex, but often more severe in males
  • Worsens with drugs (steroids, testosterone, contraceptives), oils/tars, heavy clothing and tropical climates
  • Non-inflammatory acne is due to open and closed comedones
  • Open comedones: small follicular papules with central, black keratin plug (due to oxidation of melanin)
  • Closed comedones: follicular papules with a deeper plug below the surface
  • Follicles may rupture and become inflamed
  • Diverse lesions such as comedones, papules, pustules, cysts, sinuses and scars
Treatment
Clinical Images

Images hosted on other servers:

Various images

Micro Description
  • Three major components are comedones, inflammatory lesions and scars
  • Comedones (open or closed) are cyst-like cavities filled with compact mass of keratinous material and numerous bacteria
  • Closed comedo has 1 - 2 hairs trapped in lumen and atrophic, sebaceous acini
  • Open comedo has 10 - 15 hairs in lumen, and sebaceous acini are atrophic or absent
  • Epithelial lining of comedones is usually thin