inflammatory skin diseases Flashcards
what is the function of B lymphocyte
- recognise antigen
- produce specific IgE antibody
what is the function of T lymphocyte
- provide help for B lymphocytes
what is the function of mast cells
inflammatory cells that release vasoactive substance
mast cells produce vasoactive substances. What substances are preformed and which are synthesised on demand
Preformed
- histamine
- tryptase
- heparin
Synthesised on demand
- leukotrienes
- prostaglandins
- cytokines including IL4 and TNF
what are defining and serious features of anaphylaxis?
Airway
- laryngeal and or pharyngeal oedema
Breathing
- bronchospasm (wheeze)
- tachypnoea (increased respiratory rate)
Circulation
- tachycardia ( reface, compensatory )
- hypotension and potential collapse (vasodilation, increased vascular permeability)
Other common features
- urticaria
- angioedema
- allergic rhinitis
- allergic conjunctivitis
what are soluble mediators of the innate immune response
- acute phase protein - CRP
- cytokines
- complement
what is the immunology of type 1 immediate hypersensitivity
- IgE antibody on cell surface passively sensitises cell
- antigen binds to antibody and activates cell membrane
- release of histamine, heparin, other chemotactic factors (ECF,NCF), PAF, leukotrienes, prostaglandins
what are cutaneous examples of Type 1 hypersensitivity
- urticaria - caused by dilated blood vessels and leakage of fluid into surrounding tissues
- angio-oedema - a deeper cuteness reaction than urticaria, causes swelling of sub-cutenous tissues including mucous membranes
- anaphylaxis - life threating generalised reaction, with urticaria and/or angio-oedema, laryngeal swelling, bronchospasm, hypotension or shock
what are cutaneous examples of type 4 (delayed) hypersensitivity
- allergic contact dermatitis
- photo allergy (delayed reaction to sun exposure)
- skin response to bacteria, fungi and viruses
- abnormal delayed response in atopic eczema
what are factors that increase the potential of topical steroids to cause side effects
- duration of therapy
- steroid potency use
- extent of application
- occlusion
- thin skinned
- inflamed skin
what are some reversible steroid effects
- contact allergy to hydrocortisone
- unstable pustular psoriasis can be triggered as a “rebound” when topical steroid therapy is withdrawn from chronic plaque psoriases
- poor wound healing
- pigmentary changes
- tinea incognito - fungal infection masked by inappropriate use of topical steroid
- tachyphylaxis
- acneifrom eruptions
- pustules in hair follicles
what are permeant effects of steroids
- atrophy, brusising (ecchymoses)
- striae
- glaucoma, cataract
- hirsutism
- poor wound healing
