Anaphylaxis, Angioedema and Urticaria Flashcards
What is urticaria?
Swelling involving the superficial dermis, raising the epidermis.
Itchy wheals
What is another term used for urticaria?
Hives
What causes urticaria?
A local increase in permeability of capillaries and small venules. Due to a number of inflammatory mediators, especially histamine released from mast cells (also prostaglandins, leukotrienes).
Mediator release can be due to immunological or non-immunological mechanisms.
What do urticaria wheals look like?
They can be a few millimetres or several centimetres in diameter, coloured red or white, with or without a surrounding ref flare.
Each wheal may last a few minutes or several hours.
The shape may be round, form rings, map like or giant patches.
Can affect any site of the body.
Is urticaria itchy?
Yes and can have a burning like sensation.
What causes urticaria?
Acute viral infection - URTI, viral hepatitis
Acute bacterial infection - dental abscess, sinusitis
Food allergy (IgE mediated) - milk, eggs, peanut, shellfish
Drug allergy (IgE mediated) - often an antibiotic, contrast medium, opiates, NSAIDS
Insect bites
Vaccination
Contact - latex
Hereditary
What is angioedema?
Swelling involving the dermis and subcutaneous tissues.
Where does angioedema most commonly occur?
Eyes
Lips and tongue
In severe cases can occur in the internal lining of upper respiratory tract and intestines
Urticaria only affects the skin, but angioedema can also affect what?
Mucosa
What is the mechanism behind the swelling in angioedema?
Small blood vessels in the subcutaneous and/ or submucosal tissues leak watery liquid through their walls and cause swelling. (The dame thing happens in urticaria but closer to the skin surface).
What makes up the subcutaneous tissue?
Fat, connective tissue, vessels
(Also called adipose tissue)
Connects the dermis to underlying structures
What are the physical signs of angioedema?
Red or skin coloured swellings occurring below the surface of the skin.
May or may not be itchy.
Often accompanied by pain and tenderness.
What are the 4 main types of angioedema?
Acute allergic
Non-allergic drug reactions
Idiopathic
Hereditary
Why can angioedema be dangerous?
In severe cases swelling of the throat or tongue may make it difficult to breath
Does ACE inhibitor angioedema occur with or without urticaria?
Without
Acute allergic angioedema occurs almost always with urticaria. True or false?
True
What is anaphylaxis?
Also known as anaphylactic shock- a serious reaction that can come on rapidly and lead to death. It typically includes: bronchospasm, facial and laryngeal oedema, hypotension.
It can present initially with urticaria and angioedema.
In anaphylaxis what symptoms can occur associated with the CVS?
Chest pains
Rapid or irregular heartbeat
Hypotension
In anaphylaxis what symptoms can occur associated with the GI tract?
Cramps
Nausea
Vomiting
Diarrhoea
What systemic symptoms are associated with anaphylaxis?
Confusion
Dizziness
Tremor
Collapse
At least how many organ systems should show symptoms of anaphylaxis to make a diagnosis?
2
How is anaphylaxis treated?
Stabilise the airway
IM adrenaline
Corticosteroids
Antihistamines
What is Stevens-Johnson syndrome?
A rare, serious disorder of the skin and mucous membranes. At least 2 mucosal sites are involved. Skin involvement may be limited or extensive.
Often it begins with flu like symptoms, followed by a painful red or purple rash that spreads and blisters. The top layer of skin dies, sheds then heals.
What typically causes Stevens-Johnson syndrome?
Reaction to a medication or infection.
