Urticaria and Mastocytosis Dan Flashcards
T/F
Angioedema is itchy
False
painful not itchy
What is the definition of chronic urticaria?
more than 6 weeks duration
continuous urticaria occurring at least twice a week off treatment
What are the causes and mimics of acute urticaria?
Causes; Primary/Idiopathic 50% Secondary causes; Infection Drug eruption Contact urticaria Inhaled allergen urticaria Non immune drug/food urticaria Scombroid fish poisoning Serum sickness-like rcn
Mimics; AHOC SCLE EM, SJS onset of DH, Linear IgA, EBA PEP/PUPPP PMLE Sweets Neutrophilic eccrine hidradenitis Toxic erythemas
What are the causes and mimics of chronic urticaria?
Causes; Primary = Chronic Spontaneous Urticaria Secondary causes; Chronic infection AI disease Drug reaction Chronic inducible urticaria - MASTS Cutaneous mastocytosis
Mimics; Autoinflammatory syndromes Schnitzler’s syndrome Urticarial vasculitis Urticarial dermatitis Neutrophilic urticarial dermatitis Pre-bullous BP MF Eosinophilic dermatosis of haematological malignancy/ exaggerated insect-bite reaction Annular erythemas Wells syndrome
What are the major types of Inducible (physical) urticarias?
MASTS (as in mast cells) Mechanical Aquagenic urticaria Solar Urticaria Thermal Stress
What are the types of mechanical urticarias?
Dermatographism • Immediate Simple dermatographism Symptomatic dermatographism • Delayed dermatographism Delayed pressure urticaria Vibratory angioedema • Inherited • Acquired
What are the types of thermal urticarias?
Heat contact urticaria
Cold contact urticaria
• Primary
• Secondary (cryoglobulins, cryofibringen)
• Reflex
(Familial - autoinflammatory syndrome not an inducable urticaria)
What are the types of stress-induced urticarias?
Cholinergic urticaria Adrenergic urticaria Exercise-induced urticaria • Exercise-induced anaphylaxis • Food- and exercise-induced anaphylaxis
What are the histo findings of urticaria?
An invisible dermatosis Epidermis normal Dermal oedema Sparse perivascular and interstitial inflammatory infiltrate of eosinophils, lymphocytes, neutrophils, and/or mast cells Neuts +/- eos in vessels
What questions are important for screening for autoinflammatory disorders?
Any; Fevers malaise Joint pains NB consider delayed pressure urticaria or urticarial vasculitis also
T/F
Angioedema occurs in 50% of cases of urticaria
True
esp face, lips, eyelids etc
May also get mucosal swellings of oral cavity but usually not larynx
T/F
cow’s milk allergy is commonest cause of urticaria in infants under 6 months old
True
What are the causes of acute and chronic urticarias in young children?
Acute
Common reaction to URTI or other infection inc glandular fever (EBV)
Other acute causes – AHOC, scarlet fever, serum-sickness-like rcn, drug rcn
Chronic
If chronic/recurrent think of Urticaria pigmentosa or food allergy - esp cow’s milk allergy
What are the major causes of acute urticarias and what proprtion of cases do they account for?
Does not include insect bites and stings responsible for many cases
Idiopathic 50%
Infection 40% esp URTI
Drugs 9% (several mechanisms)
Foods 1% (allergy or histamine releasers)
Others;
Inhaled allergens
- Grass pollens, mould spores, animal danders, house dust mites
Contact urticaria
- Food most common
- Latex
Which foods should be avoided if latex allergic due to cross-reactions?
Kiwi Chicks Like bananas and Avos Kiwi Chestnuts Lychees Bananas Avocado
Which foods cause most type 1 acute (contact) urticaria?
Fish, nuts, milk, crustaceans, spices, apples, peaches
Which foods cause direct histamine induced urticaria (non-allergic)?
histamine containing – cheese, fish, meat, tomatoes, pineapple, avocados
Esp fish with scombroid poisoning
histamine-releasing – strawberries, alcohol
What is Scombroid fish poisoning?
underprocessed tuna, mackeral where bacteria has generated histamine by histidine decarboxylase leading to acute uticaria, vomiting, diarrhoea
Which drugs cause urticaria?
Almost any drug can cause an urticarial eruption as a side effect (not type 1 allergy)
e.g.
Antibiotics, vaccines, radiocontrast media, antidepressants, antihypertensives, antihistamines (H1 and H2!), antifungals, antiplatelets, NSAIDS, OCP, HRT
Bleomycin, asparginase, cyclophosphamide, chlorambucil, daunorubicin
Imatinib, Nilotinib, Dasatinib
some cause true type 1 allergy and anaphylaxis
some cause anaphylactoid reactions via direct histamine release e.g.
Opiates (morphine, codeine)
Antibiotics (vancomycin ‘red man syndrome’)
Iodine based radiocontrast dyes
Aspirin and NSAIDs
Also alcohol
T/F
Antihistamines can cause urticarial drug eruptions
True
T/F
NSAIDs can cause urticarial drug eruptions either by an allergic side effect mechanism or direct histamine release effects
True
T/F
NSAIDs can trigger mast cell degranulation in mastocytosis but can also be used to treat mastocytosis
True
can reduce flushing due to anti-prostaglandin effects
Introduce catiously along with antihistamine esp if Hx of intolerance
What are the major causes of chronic urticarias and what proprtion of cases do they account for?
60% Primary chronic urticaria - Autoimmune - Pseudoallergic - food, drug - Infection-related - Idiopathic = chronic spontaneous urticaria 35% Inducible urticaria 5% Urticarial vasculitis
T/F, Regarding chronic spontaneous urticaria;
30%-50% due to activating IgG autoantibodies to alpha subunit of FcεRI (high affinity mast cell surface receptor), or less frequently against receptor-bound IgE
True
Cause of the remainder unknown but some may be unidentified Autoimmune, Pseudoallergic or Infection cases