Hives Flashcards
What are hives?
Reddened, itchy welts that may be triggered by exposure to certain foods, medications, or other substances
What is the classic look of uticaria (hives)?
raised welts that move and change shapes
they are very itchy
What do we do when we see an atypical skin condition?
Refer to MD
What is the etiology of hives?
allergic and non-allergic
What are the allergic causes of hives?
Foods and drugs
Anything can cause hives and you can get a skin reaction
What are the non-allergic causes of hives?
foods, drugs
URTI (common in kids)
pressure/vibration
cold temperature
nerves
What is a common cause of rash in kids?
Virus or viral upper respiratory infection
Responsible for 40% of hive rashes
The virus causes the rash and not the drug
Hives last for 4-24 hours
True or False: Foods cause hives
False. An allergy to foods is pretty rare. 1% of hive sufferers
What is responsible for causing hives in the body?
High levels of histamine, can be due to stress
What medications cause hives?
The most common culprit are antibiotics
Heart medications (BB, ACEi, Diuretics, ASA)
Pain medication (NSAID, Muscle relaxers, Codeine, Morphine)
Radicontrast dye, Dextran, Quinine
Some of the above drugs cause histamine release from mast cells
Are hives caused by medications common?
No, only 10% of hives caused by meds
What is dermatographism?
An immunologic response to pressure applied to the skin
Local wheal-and-flare erythema followed by edema and itch
Begin within 5mins and persist for 15-30 minutes
What is the clinical presentation of hives?
Lesions can last 1-24 hours up to several days
Lesions change locations and move around
Very itchy
20% of the population have had it
Chronic form is 1%
Usually benign
Hives worse at night (due to lower cortisol)
How to tell if someone has hives?
It has to be itchy
Lesions cannot last for 24 hours in the same spot, otherwise it is something else
Are most hives allergy based?
No, the main cause is still URTI
Allergies are only 1-3% of cases and will last 1-2 weeks (antibiotic)