Allergies

• The body’s reaction to something that is normally harmless (Patient Education – Allergies); exaggerated immune response to benign antigens – it is the immune response, not the antigen, that is harmful to the host (Chap 65: Hypersensitivity (Allergies) In: Review of medical microbiology and immunology); hypersensitivity reactions occur due to external (non-self) antigens; auto-immune responses occur due to internal (self) antigens
• Hypersensitivity reactions are antigen-specific
  • First contact with antigen sensitizes/primes the immune system
  • Subsequent antigen exposures will result in clinical manifestations that may increase with time (Review of Medical Microbiology…); once body sensitive to substance, it will react every time – can be mild or life-threatening (Patient Ed)
  • Can have immediate reac ...