Urticaria & Angioedema Flashcards
urticaria is characterized by . . .
rapid onset of lesions called wheals
wheal
- central mid-dermal swelling w/ or w/o surrounding erythema w/ associated pruritus
- lasts from 30 min. - 24 hrs
- they blanch
angioedema
- deeper swelling (dermis and SQ tissue) w/i skin or mucous membranes
- ill defined
- lasts up to 72 hrs
- may be itchy, painful, or asx
areas commonly affected by angioedema
- face (eyelids and perioral sites)
- hands
- feet
- genitalia
- tongue, uvula, soft palate, larynx
respiratory involvement of angioedema
-may target GI and/or resp. tract causing abd pain, coryza, asthma, obstruction, anaphylaxis and hypotension
2 subsets of angioedema
- deep urticaria w/ or w/o hives
- hereditary / ACE inhibitor associated
deep urticaria w/ or w/o hives
- angioedema d/t the reaction of histamine release
- pruritis may be significant feature
hereditary / ACE inhibitor associated angioedema
- hereditary: associated w/ acquired C1 esterase inhibitor deficiency
- not pruritic and no hives
- pain sx are predominant
duration of urticaria: chronic vs. acute
- acute urticaria: < 6 weeks
- chronic urticaria: > 6 weeks
pathophys of urticaria
-mast cell degranulation w/ release of histamine
w/ ACE associated and hereditary the mediator is bradykinin
what kinds of stimuli can lead to mast cell activation?
- infections
- drugs
- foods
- inhalants
- emotional stress
- systemic dz
what major systemics diseases can lead to mast cell activation?
- lupus erythematosus
- thyroid disease
MC causes of acute urticaria
- infections
- adverse reactions to medications
Chronic urticaria
- F>M
- idiopathic > autoimmune
- hives can stick around from weeks to years
physical urticaria
- a form of chronic urticaria
- MC in ages 17-40
- caused by a physical stimulus leading to mast cell degranulation
dermatographism
- shearing forces on skin
- may present as urticarial lesions at site of scratching
cold urticaria
- sudden exposure to cold incites stimulus
- occurs during rewarming
delayed pressure urticaria
- 4-6 hr after prolonged pressure
- MC on palms and soles
heat urticaria
direct contact w/ a warm object incites stimulus
cholinergic urticaria
-rise in core body temp secondary to exercise, hot water, or stress
contact urticaria
contact w/ chemicals found in food, plants, medicines
solar urticaria
UV or visible light
aquagenic urticaria
- very rare
- caused by contact w/ water of any temp.
what to r/o for urticaria
- urticarial vasculitis
- bullous pemphigoid
- urticaria pigmentosa
- papular urticaria (bug bites)
urticarial vasculitis
- causes persistent urticaria-like plaques that lasts> 24 hrs and resolve w/ bruising, non-blanching
- painful > itchy
- bx to differentiate
urticaria pigmentosa
- localized tan “mole” that swells and itches when stimulated
- doesn’t move
presentation of papular urticaria aka bug bites
- grouped or linear
- in a “breakfast, lunch, dinner” pattern
clinical steps if urticaria is acute and recurrent
- consider food diary
- order RAST to detect specific IgE
clinical evaluation of angioedema in absence of urticaria
-measure C4/C1-esterase inhibitor b/c it’s likely CI esterase def., hereditary or ACE-I
clinical eval in chronic urticaria
- ask about: thyroid dz, CTD, infection, jaundice, hepatitis, Lyme, sinus, strep, UA, dental films
- order: CBC w/ diff, CMP, ANA, TSH, thyroid ABs, hepatitis panel
what is the mainstay of tx for acute urticaria?
- antihistamines:
- 2nd generation are non drowsy
- 1st gen cross the BBB and cause drowsiness
- use until sx are controlled then 4-6 weeks more
other txs for acute urticaria
- stop the causative drug
- start hypoallergenic products
- prednisone taper if severe
- ice, cool baths
- refer to allergy
- epinephrine for anaphylaxis
oral 2nd generation antihistamine options
- cetirizine
- loratidine
- fexofenadine
- desloratadine
- levocetirizine
- nightly Singular
what to r/o in chronic urticaria
physical utricaria w/ challenge test
Tx of chronic urticaria
- antihistamines
- doxepin
- singular
- hydroxychloroquine
- prednisone
- cyclosporine
- cellcept
- dapsone
- xolair
omalizumab (xolair)
- monocolonal antibody directed against IgE w/ low toxicity - good for those resistant to antihistamines
- new drug
