Skin Inflammation Flashcards
What cells are found in the skin during inflammation?
Neutrophils, eosinophils, lymphocytes, plasma cells, macrophages and mast cells
What are Langerhans cells?
Dendritic cells the pick up antigens that enter the skin and transport them to lymph nodes where they present the antigen to CD4+ helper T cells
Where are Langerhans cells found?
In the epidermis
Why does skin become red and hot during inflammation?
Increased blood flow and vessel dilatation
Name the five different types of skin inflammation
Mast-cell mediated Antibody-mediated Immune-complex mediated Delayed hypersensitivity Granuloma formation
Outline mast-cell mediated inflammation
An inhaled or ingested pathogen is presented to an APC. The APC presents the antigen to a Th2 cell which then secretes several factors which activates eosinophils to release granules and B cells to produce IgE which will activate mast cells to release their contents too. This leads to vascular leak, broncho-constriction, increased gut motility, inflammation and tissue remodelling.
What is released during mast cell degranulation?
Histamine, leukotrienes, prostaglandin and platelet aggregating factor (PAF)
What substances can trigger mast cell degranulation?
Drugs (aspirin, NSAID), serum factors, insect stings, nuts, shell fish, house dust mites
What are the effects of mast cell degranulation?
Increased vascular permeability, broncho-constriction, increased gut motility, inflammation and tissue remodelling
Outline the main role of histamine on the body (after mast cell degranulation)
Stimulates sensory nerves (causes itching)
Bronchospasm
Arteriole dilatation (causes headache and hypotension)
Smooth muscle contraction (leads to vessel leakage and oedema)
What component of dust mites allow it to act as an allergen to stimulate mast cell degranulation?
Contains Der P1 in faecal pellets which cleaves tight junctions in gut mucosa
What are localised examples of mast cell-mediated inflammation?
Urticaria, asthma and hay fever
What is generalised mast-cell-mediated inflammation known as?
Anaphylaxis: antigen released into the blood stream will bind to the IgE on basophils which will cause a massive release of inflammatory mediators causing bronchospasm and circulatory collapse
What is urticaria?
Skin condition that causes lumps under the skin.
What is cutaneous dermographism?
Where you can gently touch the skin and it will become so inflamed under the touch that you can physically see where the touch has been. This is a characteristic sign of urticaria.