Risk Factors and Causes of Rashes

A personal or family history of allergies or asthma increases the risk for rashes. People who spend a lot of time outdoors are at increased risk certain types of rashes, including poison ivy, poison oak, poison sumac, and those caused by insect bites.

Common causes for rashes include the following:

  • Allergic reaction (e.g., resulting from an animal allergy, drug allergy, or food allergy)
  • Bacterial infection (e.g., impetigo)
  • Drug side effect
  • Excessive skin rubbing (friction)
  • Fungal infections (e.g., athlete's foot, ringworm)
  • Insect bites (e.g., tick, flea, spider, mosquito)
  • Parasite infection (e.g., scabies)
  • Prolonged exposure to heat, moisture, or irritants (e.g., heat rash, diaper rash, contact dermatitis)

Certain medical conditions can result in a rash, including the following:

  • Acne (often develops on the face, neck, back, and shoulders)
  • Lupus (commonly causes a "butterfly" rash across the cheeks and under the eyes)
  • Lyme disease (usually transmitted by the bite of an infected deer tick; causes a "bull's eye" rash)
  • Psoriasis (typically causes round, red lesions with sharply defined edges and overlying silvery white scales [called plaques]; usually begins as small spots that progressively involve very large areas)
  • Rosacea (often occurs on the forehead, nose, and chin)

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Jan 2007

Last Modified: 02 Oct 2015