Cutaneous inflammation Flashcards
What are the cardinal signs of acute inflammation
Heat
Redness
Swelling
Pain
Why is redness and heat seen in inflammation?
Increased blood flow and vessel dilation
Why is swelling seen in inflammation
Accumulation of fluid
Why is pain seen in inflammation
Pressure on nerve endings leads to loss of function
What cells are found in the skin during inflammation
Neutrophils Eosinophils Lymphocytes Plasma cells Macrophages Mast cells
Where are Langerhans cells found
Epidermis
What kind of cells are Langerhans cells
Dendritic cells- spine like projections
What do Langerhans cells do
Present antigen to CD4+ helper T cells
Pick up antigens that enter the skin and transport them to lymph nodes
What do IL-17, IL-17F, IL-22 have in common
They all target extracellular bacteria and fungi y causing neutrophillic inflammation
What does IFN- gamma target
Intracellular abcteria, protozoans, viruses
What targets helminths
IL-4, IL-5, IL-13, IL-25
What results from mast cell mediated inflammation
Urticaria
What results from antibody mediated inflammation
Pemphigus
What results from immune complex mediated inflammation
Vasculitis
What results from delayed hypersensitivity
Contact allergic dermatitis
Describe the steps of mast cell mediated reaction
- Inhaled trigger
- TH2 cell releases IL-4, IL-5
- B cells release IgE antibodies which go to mast cells causing release of IL-3, IL-5
- Goes to eosinophil
- Release of granules
What can cause mast cell degranulation
- Drugs
- Insect sting
- Nuts
- Shell fish
- House dust mite
What mediators are released from mast cells
Histamine
Leukotrienens
Prostaglandins
Platelet aggregating factor
What is the effect of mast cell granulation on
a) vascular system
b) lungs
a) vascular leak
b) broncho-constriction
What is the effect of mast cell granulation on intestines
Intestinal hypermotility
What are the roles of histamine (5)
1- Stimulate sensory nerves (itch)
2- Smooth muscle contraction (vessel leakage and oedema)
3- Arteriole dilation (headache and hypotension)
4- Modulation of immune response via H2 receptors
5- Bronchospasm
What allergic exists in faecal pellets of dust mites
Der P1
What is the action of Der P1
Breaks down components of tight junctions which helps it cross the mucosa
How does anaphylaxis come about
- Antigen released into blood stream
- Binds to IgE on basophils
- Massive release of inflammatory mediators
- Bronchospasm and circulatory collapse
What is cutaneous dermographism
When you can write on somebody
Features of acute angioedema
Lower lip swelling
Uvular and tonsillar swelling
What can be used to treat resistant urticaria and asthma
Omalizumab
What antibody is involved with pemphigus vulgaris
IgG
Histological signs of pemphigus vulgaris
Suprabasal splitting in PV
Acantholysis- loss of cohesion between keratinocytes
How is pemphigus vulgaris treated
Oral steroids
Rituximab
What happens in immune complex mediated vasculitis
- fibrin deposition
- necrosis of vessel wall
- proteases degreade vessel BMZ
- leaky vessel extravasation of blood and oedema
What are the early cutaneous manifestation of vasculitis
Erythema and oedema
What are the established cutaneous manifestation of vasculitis
Palpable purpura
What are the severe cutaneous manifestation of vasculitis
Ulceration and necrosis
What histological findings will there be in Leukocytoclastic Vasculitis
Fibrin in blood vessel
Nuclear dust
What 2 cytokines promote TH1 response
IL-2 and IFN- gamma
What do TH1 cells secrete
- IL-2
- IL-3
- GM-CSF
- IFN-g
- TNF
How are granulomas formed
Clonal T cell expansion
Secretion of TH1 cytokines
Macrophages
What can cause granuloma formation
- TB
- Sarcoidosis
- Foreign body granuloma
When does an autoimmune disease occur
When the immune system fails to recognise the bodys own tissue as self and mounts an attack on it
