Drug induced urticaria, angioedema Flashcards
(25 cards)
What is the prevalence of drug-induced urticaria in medical inpatients?
0.16%
This statistic highlights the occurrence of drug-induced urticaria among hospitalized patients.
What percentage of chronic urticaria/angioedema cases in the Emergency Department are drug-induced?
9%
This indicates a significant proportion of chronic cases linked to drug exposure.
What is the primary cause of drug-induced urticaria in children?
Food
This contrasts with adults, where drugs are the more common trigger.
What is the primary cause of drug-induced urticaria in adults?
Drugs
This includes various medications that may trigger allergic reactions.
What type of immunological response is involved in drug-induced urticaria?
Drug-specific IgE, immediate hypersensitivity
What is the consequence of cross-linking of IgE on mast cells?
Inflammatory mediated release (histamine)
This process leads to the symptoms associated with urticaria and angioedema.
What are the clinical features of urticaria?
Transient, pruritic erythematous and oedematous papules/plaques
These can occur anywhere on the body, including palms, soles, and scalp.
How soon can urticaria appear after initial drug exposure?
24-36 hours
This timing indicates the delayed response to the first exposure.
How quickly can urticaria reappear upon re-exposure to a drug?
Minutes to less than 1 hour
This highlights the rapid response upon subsequent exposure.
What tests can help detect specific IgE to drugs?
Prick tests and RAST
RAST tests are often limited to specific drugs like penicillin, cephalosporin, and insulin.
What is the most common cause of drug-induced urticaria?
Penicillin and cephalosporin
Other common culprits include sulphonamides and minocycline.
What is angioedema?
Transient oedema of deep dermal/SC/submucosal tissue
This condition can occur alongside urticaria.
What percentage of angioedema cases are associated with urticaria?
50%
This indicates a significant overlap between these two conditions.
What is a common cause of drug-induced urticaria?
penicillin and cephalosporin > sulphonamides and minocycline
What is the most common presentation of angioedema?
Acute, asymmetrical pale or pink SC swelling involving the face
This can lead to serious complications if the oropharynx is involved.
What are common culprits for angioedema?
- ACE-I
- Penicillins
- NSAIDs
- Contrast media
- Monoclonal antibodies
- ARBs
These drugs can trigger angioedema in susceptible individuals.
What is anaphylaxis?
A severe allergic reaction occurring within minutes, usually after parenteral administration
It can include systemic signs such as tachycardia and hypotension.
What is the incidence of anaphylaxis following penicillin exposure?
1 in 5000 exposures
This indicates the rarity of such severe reactions.
What is the mainstay of treatment for anaphylaxis?
SC adrenaline 0.5mg IM and systemic steroids
Immediate treatment is crucial for managing anaphylactic reactions.
What can limit the response to adrenaline in anaphylaxis treatment?
Patients on B-blockers
This can complicate the management of anaphylaxis.
What types of reactions do NSAIDs and contrast media often cause?
Anaphylactoid reactions rather than anaphylaxis
These reactions can mimic anaphylaxis but are not true allergic responses.
What should be done to manage drug-induced urticaria/angioedema/anaphylaxis?
- Stop the trigger
- Oral/IV antihistamines
- Oral/IV corticosteroids
- SC adrenaline
*epipen education and script
These steps are essential for effective management.
What is the expected disease course after withdrawal of the triggering drug?
Improvement within 1-2 days
This emphasizes the importance of identifying and stopping the offending drug.
What should be monitored for after anaphylaxis?
Late phase reaction 5-6 hours afterwards
This can occur even after initial treatment appears effective.
