allergology the branch of medical science that studies the causes and treatment of allergies
TRANSCRIPT
ALLERGOLOGY
The branch of medical science that
studies the causes and treatment of
allergies
Allergy• a disorder of the immune system often
also referred to as atopy
• occur to normally harmless environmental
substances known
as allergens
• allergy is one of four forms of hypersensitivity and is called type I (or immediate) hypersensitivity
• characterized by excessive activation of certain white blood cells called mast cells and basophils by a type of antibody known as IgE, resulting in an extreme inflammatory response
What is hypersensitivity?
• Abnormal sensitivity, a condition in which there is an exaggerated response by the body to the stimulus of a foreign agent. example: allergy
Comparison of hypersensitivity types
Type Alternative namesOften mentioned
disorders Mediators
I Allergy (immediate)
Atopy
IgEAnaphylaxisAsthma
IICytotoxic, antibody-dependent
Autoimmune hemolytic anemia IgM or IgGThrombocytopenia (Complement)Erythroblastosis fetalis Goodpasture's syndrome
IIIImmune complex disease
Serum sickness IgGArthus reaction (Complement)Systemic lupus erythematosus (SLE)
IV
Delayed-type hypersensitivity (DTH), cell-mediated immune memory response, antibody-independent
Contact dermatitis
T-cells
Mantoux testChronic transplant rejection
Multiple sclerosis
V Autoimmune disease
Grave's disease IgM or IgGMyasthenia Gravis (Complement)Hashimoto's thyroiditis Systemic lupus erythematosus
Common Allergic Reaction• Hives• hay fever• Asthma• Food allergies• Reactions to the venom of stinging insects such as wasps and bees
Affected Organ Symptom
NoseNose Swelling of the nasal mucosa (allergic rhinitis)Swelling of the nasal mucosa (allergic rhinitis)
SinusesSinuses allergic sinusitisallergic sinusitis
EyesEyes redness and itching of the conjunctiva (allergic conjunctivitis)redness and itching of the conjunctiva (allergic conjunctivitis)
AirwaysAirways sneezing, coughing, and sometimes outright attacks of asthma sneezing, coughing, and sometimes outright attacks of asthma
EarsEarsfeeling of fullness, possibly pain, and impaired hearing due to the lack of feeling of fullness, possibly pain, and impaired hearing due to the lack of eustachian tube drainageeustachian tube drainage
SkinSkin rashes, such as hives (urticaria)rashes, such as hives (urticaria)
Gastrointestinal Gastrointestinal tracttract abdominal pain, vomiting and diarrheaabdominal pain, vomiting and diarrhea
Cause Risk factors for allergy can be placed in two
general categories, namely host and environmental factors.
• Host factor:– heredity, sex, race, and age
• Environmental factor:– alterations in exposure to infectious diseases during
early childhood, environmental pollution, allergen levels, and dietary changes
– Aside from these ambient allergens, allergic reactions can result from foods, insect stings, and reactions to medications like aspirin and antibiotics such as penicillin.
Treatment• Pharmacotherapy
– several antagonistic drugs are used to block the action of allergic mediators, or to prevent activation of cells and degranulation processes. These drugs help to alleviate the symptoms of allergy, and are imperative in the recovery of acute anaphylaxis, but play little role in chronic treatment of allergic disorders.
• Immunotherapy– Desensitization or hyposensitization is a treatment in
which the patient is gradually vaccinated.