Skin Inflammation

Question 1

What are the signs of inflammation?

Answer 1

• heat (increased blood flow and vessel dilatation)
• redness (increased blood flow and vessel dilatation)
• swelling (accumulation of fluid)
• pain (pressure on nerve endings)
• loss of function

Question 2

What are the different types of inflammation in skin?

Answer 2

• urticaria = mass cell mediated (oedema and inflammation of dermis)
• pemphigus (antibody mediated)
• vasculitis (immune complex mediated)
• contact allergic dermatitis (delayed hypersensitivity)
• TB, sarcoidosis (granuloma formation)

Question 3

What activates mast cell mediated inflammation?

Answer 3

• IgE release histamine, leukotrienes and PGs via mast cell binding
• Th2 cells which have had the antigen presented to them produce IL4,5,GM-CSF which produce B cells producing IgE

Question 4

What is the role of histamine?

Answer 4

• stimulates sensory nerves (itch)
• smooth muscle contraction (vessel leakage and oedema)
• arteriole dilatation (headache and hypotension)
• modulation of immune response via H2 receptors
• bronchospasms

Question 5

What is Der P1?

Answer 5

• allergen
• from faecal pellets of dust mite
• breaks down components of tight junctions
• help it cross mucosa
• then get immune response

Question 6

What are local allergic reactions?

Answer 6

• urticaria
• asthma
• hay fever

Question 7

What are generalised allergic reactions?

Answer 7

anaphylaxis:

• antigen release into blood stream
• binds to IgE on basophils
• massive release of inflammatory mediators
• bronchospasm and circulatory collapse

Question 8

What are signs of acute angioedema?

Answer 8

• lower lip swelling
• uvular and tonsillar swelling
• closure of pharynx so cannot talk
• need EpiPen/adrenaline

Question 9

What is omalizumab used for?

Answer 9

• new treatment for resistant urticaria and asthma

Question 10

What is pemphigus vulgaris?

Answer 10

• autoimmune blistering disorder
• IgG antibodies bind to desmoglein-3 (part of desmosome)
• leads to suprabasal split and acantholysis
• loss of cohesion between epidermal keratinocytes

Question 11

What is the treatment for pemphigus vulgaris?

Answer 11

• oral steroids
• immunosuppression
• rituximab

Question 12

What is immune complex mediated vasculitis?

Answer 12

IgG activated complement:

• deposition of fibrin
• necrosis of vessel wall due to microthrombi blocking vessel
• proteases degrade vessel BMZ
• leaky vessel extravasation of blood and oedema

Question 13

What are some cutaneous manifestations of immune complex mediated vasculitis?

Answer 13

• early = erythema and oedema
• established = palpable purpura
• severe = ulceration and necrosis

Question 14

What are some examples of human immune complex diseases in skin?

Answer 14

• systemic lupus erythematosus (DNA and anti-DNA)

- polyarthritis nodose HbsAG (anti-HBs antibody)

Question 15

What is an example of delayed hypersensitivity?

Answer 15

Contact dermatitis

• wrist-nickel
• watch
• nickel, belt buckle
• rubber in elastic clothing
• topical antibiotics
• primula

Question 16

What is the role of IL-2 and IFN gamma in contact dermatitis?

Answer 16

• promote Th1 response secretion of IL-2, IL-3, IFN gamma

- promotes macrophage-rich response

Question 17

What are examples of granuloma formation?

Answer 17

• sarcoidosis
• lupus vulgaris -> cutaneous TB
• treat with JAK inhibitor = ruxolitinib

Question 18

What are the cells found in skin during inflammation?

Answer 18

• neutrophil
• eosinophil
• lymphocyte
• plasma cell
• macrophage
• mast cell

Question 19

What is the langerhan cell?

Answer 19

• in the epidermis
• has dendritic cell spine like projections
• presents antigen to CD4+ helper T cell
• picks up antigen entering skin and transport to lymph node

Question 20

What can cause mast cell degranulation?

Answer 20

• Drugs - aspirin and NSAIDs
• serum factors
• insect sting
• nuts
• shell-fish
• house dust mite

Question 21

What do mast cells release?-

Answer 21

• histamine
• leukotrienes
• PG
• platelet aggregating factor

Question 22

What are the effects of mast cell degranulation?

Answer 22

• vascular leak
• bronchoconstriction
• intestinal hypermobility
• inflammation
• tissue remodelling

Question 23

How does a granuloma form?

Answer 23

• TB causes clonal T cell expansion
• secretion of Th1, cytokines IL2/IFN-y, TNF
• macrophage formation
• fuse to form giant cells/langhans giant cells = granuloma OR transform into histiocytes to form granuloma

Question 24

What are some common autoimmune skin examples?

Answer 24

• alopecia areata (autoimmunity to hair follicle)
• vitiligo (autoimmunity to melanocyte)
• treat both with strong topical steroids and immunosuppressants
• if Vitamin D levels are low they will not respond to treatment