Urticaria and Itch Flashcards
What is the dermatological diagnosis?
Urticaria
Where is the swelling located in urticaria?
What is the typical duration?
When is spontaneous urticaria considered chronic?
What is associated with angioedema and chronic spontaneous urticaria (CSU)?
What % respond to 4X dosing of antihistamines?
Upper dermis
>6weeks
Greater chance of lasting > 12 months (generally 1-6y)
50%
Where is the swelling located in angioedema?
What is the typical duration?
How often is angioedema associated with urticaria?
Deep dermis, subcutaneous or submucosal tissue
Up to 3 days
40-50%
What types of cells cause urticaria?
What are 2 types of triggers stimulate degranulation of these cells?
What type of immunoglobulin is associated with 25-30% of chronic urticaria?
What is the mechanism?
Mast cells
Immunological and non-immunological
Functional IgG autoantibodies bind IgE or have high affinity for the IgE receptor
Degranulation of mast cells leads to release of tryptase, histamine, cytokines and other mediators.
What are the 2 mechanisms of angioedema?
- Mast-cell mediated
- Idiopathic (CSU)
- Chronic inducible urticarias (cholinergic, vibratory)
- Bradykinin mediated
- Hereditary angioedema
- Acquired C1 esterase inhibitor deficiency
- Drug-induced (ACEi 3wks-10y after initiation)
- Idiopathic
What are 3 non-allergic triggers of acute urticaria
- Histamine liberators (opiates [codeine, morphine], radiocontrast media)
- Pseudoallergic reactions (leukotriene release) - ASA, NSAIDs
- Alcohol-induced (sulphites in white wine, histamine in red wine)
Which autoimmune disorders are associated with chronic spontaneous urticaria?
- Thyroid
- Celiac disease
- SLE
List 4 types of inducible urticarias
- Mechanical
- Dermatographism
- Delayed pressure
- Thermal
- Cold urticaria
- Exercise-induced anaphylaxis
- Food/exercise induced anaphylaxis
- Solar
- Cholinergic
- Other
- Aquagenic
- Contact
What is the risk associated with cold urticaria?
What is a rare secondary cause of cold urticaria?
Anaphylaxis
Cryoglobulins
What investigations are recommended for chronic spontaneous urticaria (CSU)?
What are 3 additional tests you could consider depending on clinical picture?
- CBC
- CRP/ESR
- TSH, thyroid autoantibodies
- Total serum IgE
- H. pylori
- Basophil histamine release assay or basophil activation tests (if functional antibodies suspected)
- Serum complement (if urticarial vasculitis is suspected)
- Skin biopsy (if vasculitis suspected)
List 3 measures for management of urticaria
- Loose fitting clothing
- Menthol contaning creams
- Minimize exacerbating factors (stress, heating, etc)
- Drugs
- Avoid NSAIDs if exacerbated
- Stop ACEi if angioedema without wheals
What is the recommended management approach for CSU?
What can be used as a rescue treatment when on omalizumab or cyclosporin?
- Second-generation H1-antihistamines (sgAH) x 2-4 wks
- Increase dose of sgAH (up to 4X) x 2-4 wks
- consider changing to different sgAH
- Add Montelukast
- Add Omalizumab to sgAH x 6mo
- >12yo
- Weekly UAS7 score >28
- s/c injection monthly x 6mo
- Add Cyclosporin to sgAH
Short-term prednisolone (0.5mg/kg/day x 2-3 days)
Which inducible urticaria is this 3rd line management indicated?
Anticholinergics, propranolol or danazol
Cyclosporin
Dapsone or sulfasalazine
Sun avoidance, UV desensitization/hardening
NB-UVB or PUVA
Cholinergic urticaria
Cold urticaria
Delayed-pressure urticaria
Solar Urticaria
Symptomatic dermatographism
Which 2 sgAH can be used safely in pregnancy?
- Cetirizine
- Loratadine
What treatment is useful for salicylate sensitive individuals?
Montelukast
