hope so it will be helpful :)

1. By:
Pharm D
Spring 15

4. HYPERSENSTIVITY (Allergy)
• An immune response results in exaggerated or inappropriate
reactions harmful to the host.
• Study of these hypersensitive reaction are called as
“IMMUNOPATHOLOGY”
• Term “allergy” is often equated with hypersensitivity but more
accurately should be limited to the IgE- mediated reactions.

5. CLASSIFICATION:
Main difference between them is the nature of the immune
response to the antigen.
• Immediate (faster)
• Delayed (slower)
• In 1963, Peter Gell and Robert Coombs developed
classification system for types of hypersenstivities.

6. TYPES OF HYPERSENSITIVITY:
• There are four types of allergy:
• I ( immediate, anaphylactic)… antibody (IgE)
• II ( cytotoxin)…antibody (IgG)
• III (immune complex)…antibody (IgG)
• IV (delayed)….Cell

11. Type 1 hypersenstivity (Anaphylatic)
• IMMUNOLOGIC REACTION:
• Antigen(allergen) induces IgE antibody that binds to
mast cells and basophils , when exposed to the
allergen again , the allergen cross links the bound IgE
on those cells.
• This causes degranulation and release of mediators
e.g. histamine.

14. TYPE I :
• TYPICAL TIME OF ONSET:
In minutes
CLINICAL MENIFESTATION OR DISEASE:
• Systemic anaphylaxis
• Urticaria (hives)
• Asthma
• Hay fever
• Allergic rhinitis
• Allergic conjunctivitis

15. TYPE I : (CONTINUED…)
• Food allergies(e.g., nuts , shellfish , eggs)
• Drug allergies especially penicillin
• Eczema (atopic dermatitis)
• Bee venom
• Latex gloves
• angioedema

17. TYPE II : CYTOTOXIC
HYPERSENSITIVITY
• IMMUNOLOGIC REACTION:
• Antigens on a cell surface combine with IgG antibody . This leads to
complement mediated lysis of the cells (e.g. transfusion or Rh
reactions) or autoimmune hemolytic anemia .

18. TYPE II:
• TYPICAL TIME OF ONSET:
Hours to days
CLINICAL MANIFESTATION OR DISEASE:
• Hemolytic anemia
• Neutropenia
• Thrombocytopenia
• ABO transfusion reactions
• Rh incompatibility (erythroblastosis fetalis)
• Hemolytic disease

24. TYPE III: IMMUNE COMPLEX
HYPERSENSITIVITY
• IMMUNOLOGIC REACTION:
• Antigen-antibody immune complexes are deposited in tissues
• complement is activated, and polymorphonuclear cells are attracted to
the site
• They release lysozymal enzymes, causing tissue damage.

25. TYPE III:
• TYPICAL TIME OF ONSET:
2 to 3 weeks
CLINICAL MANIFESTATION OR DISEASE:
• Systemic lupus erythematosus
• Rheumatoid arthritis
• Poststreptococcal glomerulonephritis
• IgA nephropathy
• Hypersensitivity pneumonitis

28. Systemic Lupus Erythromatosus

29. Rheumatoid Arthritis

31. TYPE IV: DELAYED (CELL-MEDIATED)
HYPERSENSITIVITY
• IMMUNOLOGIC REACTION:
• T lymphocytes activated/sensitized by an antigen release lymphokines
upon second contact with the same antigen.
• The lymphokines induce inflammation and activate macrophages,
which, in turn, release various inflammatory mediators.

32. TYPE IV:
• TYPICAL TIME OF ONSE:
2 to 3 days
CLINICAL MANIFESTATION OR DISEASE:
• Contact dermatitis
• Poison ivy
• Drug rash
• Epidermal necrolysis

34. Poison Ivy

35. Rash caused by poison ivy

36. Contact Dermatitis