Hypersensitivity Flashcards
What is hypersensitivity?
When the normally protective immune system responds abnormally, potentially harming the body. This includes allergy and autoimmunity.
What is immunodeficiency?
Partial/full impairment of the immune system, leaving the patient unable to effectively resolve infections or disease
What is Primary Immunodeficiency?
Present at birth.
Genetic disorder.
Evident during infancy/childhood.
Classified by which part of immune system affected.
What is Secondary Immunodeficiency?
Acquired later in life.
drugs/another disorder e.g., diabetes/hiv
more common than primary immunodeficiency
What are the types of hypersensitivity reactions?
Type 1 (immediate)
Type 2 (cytotoxic)
Type 3 (immune-complex mediated)
Type 4 (delayed)
Type 5 (auto immunity)
What are type 1 hypersensitivity reactions?
Involve IgE
Anaphylaxis/Asthma
What are type 2 hypersensitivity reactions?
IgG, IgM
Transfusion reaction
What are type 3 hypersensitivity reactions?
IgG, IgM
SLE
What are type 4 hypersensitivity reactions?
T cells
OFG
Organ Rejection
What are type 5 hypersensitivity reactions?
Myasthenia Gravis
Pernicious Anaemia
What are delayed hypersensitivity reactions?
Orofacial granulomatosis
Erythema multiforme
Aphthous ulceration
Type 3 BMS
What is OFG?
A disease limited to the orofacial region characterised by lymphoedema and granuloma formation
What are the general features of OFG?
Uncommon
younger age
M:F
50% atopic
crohn’s disease
What are clinical features of OFG?
painless lip/facial swelling due to lymphoedema
aphthous-like ulceration
full width gingivitis
buccal mucosa tags
buccal mucosal oedema (cobblestoning)
What is the HPC of OFG?
Gradual
Persistent unless treated
Lip swelling, oral ulceration
Persistent with exacerbation
Lower face/lips/buccal mucosa/gingival
no systemic upset
What is the pathology of OFG?
Lymphangiectasia
Lymphoedema
Non-caseating granulomata
What is the management of OFG?
Specialist treatment
Buccal mucosal biopsy
haematological investigation
patch testing
dietary avoidance
follow up and review
What are the identified allergens?
Benzoic acid (preservative)
Cinnamonaldehyde
Chocolate
What cases of OFG progress to Crohn’s disease?
Occurs in 6% of patients
What is Erythema Multiforme?
Mucocutaneous disorder with an allergic basis
What are the general features of Erythema Multiforme?
Uncommon
Adults
M:F
Fatal in some cases
What are the clinical features of EM?
Blood crusted lips (primary herpes)
Target lesions may be present on limbs
Widespread confluent oral ulceration
May have cervical lymphadenopathy
pyrexic
HPC of EM?
Sudden
10-14 days
multiple coalescing ulcers
skin and oral mucosa
Pathology of EM?
Subepithelial bullous disorder
Management of EM?
Specialist tx
excludes primary herpetic gingivostomatitis
maintain fluid intake/bed rest
systemic steroids/analgesics
chlorhexidine mw
prevents recurrence
What are identified allergens of EM?
Any infection
Drugs eg, sulphonamides
Preservatives e.g, benzoic acid
occasionally no identifiable allergen
