(HealthDay News) -- Psoriasis is an immune system disorder that causes red, scaly patches of skin.

The American Academy of Family Physicians says the following triggers can cause the disorder to flare:

  • Having an infection, such as the common cold or strep throat.
  • Having a disease that weakens the immune system.
  • Being under stress.
  • Being a smoker.
  • Irritating the skin.
  • Being exposed to cold.
  • Taking certain medications, such as beta blockers for high blood pressure.