2 - allergy & skin

Question 1

what is type I hypersensitivity?

Answer 1

• IgE mediated, immediate reaction (within 1-2 hrs) against pollen, nuts, animal dander etc

Question 2

what are some clinical presentations of type I hypersensitivity?

Answer 2

• urticaria (itchy hives like nettle sting)
• angioedema (localised swelling of subcutaneous tissue or mucous membranes)
• also can be GI like nausea, vomiting, abdo pain
• also resp stuff like sneezing, rhinorrhea, wheezing

Question 3

what are investigations of type I allergy?

Answer 3

mostly history all needed but can also do IgE blood test, skin prick or challenge test

Question 4

what is management of type I hypersensitivity?

Answer 4

• avoidance of allergen!!
• antihistamines
• corticosteroids
• adrenaline injection if anaphylactic

Question 5

what is type IV allergy?

Answer 5

= delayed hypersensitivity, T cell mediated (presents 12-24 hrs later)
against direct skin contact like preservatives or cosmetic in skin products, airborne like fragrances or plants

Question 6

what is common cause of allergic contact dermatitis?

Answer 6

nickel = most common type (like in belt buckle or cheap jewellery

Question 7

what could it be if not allergy but symptoms like dermatitis?

Answer 7

irritant contact dermatitis = nappy rash or lip lick dermatitis (not allergy but just irritation by sweat, faeces etc)