ALLERGIC REACTIONSLocalized Anaphylaxis

ATOPIC DISEASES

• Localized anaphylaxis (common allergy)

• ~20% of US population

• Limited production of IgE and sensitization of mast cells in localized areas

• Ex: Allergic rhinitis

LATE-PHASE ANAPHYLAXIS

• Takes several hours for inflammation to show

• Mast cells release chemotactic factors• Eosinophils• Neutrophils• Helper T Cells

ASTHMA

• Triggers

• 2 parts• Early response – mast cells

in lower respiratory tract• Late response –

eosinophils and neutrophils

• Treatments

FOOD ALLERGIES

• GI tract reaction

• Hives = wheal and flare

ECZEMA

• Atopic dermatitis

• IgE levels elevated

• Rash and itching

• Increased eosinophils and helper T cells

• Allergen unknown

WHY HYPERSENSITIVITY?

• B cells that produce IgA vs. B cells that produce IgE

• Atopic individuals have lower levels of IgA

• Suppressor T lymphocytes stop production of IgE – defective in atopic individuals

ALLERGIES POSITIVE?

• Sneezing

• GI contractions

• Resistance to pathogens

• Hygiene hypothesis

TREATMENT OF ALLERGIES

• Desensitization types• Tiny but increasing doses of allergens• Series of injections of allergens over weeks -- blocking antibodies• Monoclonal antibodies – anti-IgE antibodies