Allergology Flashcards
Diagnostic methods for allergic diseases
- Clinical history - age, symptoms, pattern, occupations, treatments…
- Physical examination - inspection + palpation of the lesions
- Confirmatory tests - Prick test, patch test, intradermal (imp. in Venom or drug hypersensitivities), allergen specific IgE serology
- Provocation tests
Prick test
- indication
- positive if…
- things to remember
- immediate type I hypersensitivity
- wheal >3mm
- antihistamines and antidepressants suppress skin tests for 3-7d
Patch test
- indication
- results
-delayed type IV hypersensitivity
+ –> weak positive (non vesicular)
++ –> strong positive (edematous or vesicular)
+++ –> extreme positive (ulcerative or bullous)
IR –> irritant reaction
Allergic rhinitis
- definition
- causes
- inflammation of the nasal mucosa due to allergen exposure
- atopic disease
-indoor allergens (most common = dust mites), outdoor allergens (main = pollen), chemical allergens
Allergic rhinitis
-classification
Intermittent
-<4 days per weeks or < 4 weeks
Persistent
-4 days per week and > 4 weeks
Mild - normal sleep
Moderate/severe
-abnormal sleep, impairment in daily activities, abnormal works and school, troublesome symptoms
Allergic rhinitis
-symptoms
- rhinorrhea
- sneezing
- nasal obstruction and pruritus
- with or without conjunctivitis
more than 2 or >1h on most days
-mouth breathing, recurrent sinusitis, long cough or asthma, atopic dermatitis, frequent acute otitis media
Allergic rhinitis
- diagnosis
- treatment
- history, physical examination
- lab - eosinophils, + prick test, + IgE
- anterior rhinoscopy and nasal endoscopy
- nasal provocative test for confirmation
- 1st line: oral anti-histamines
- 2nd line: intranasal anti-histamines +/- nasal decongestants
- 3rd line: add intranasal GCS +/- intranasal cromone + or LTRA
- 4th line: immunotherapy
Allergic bronchial asthma
-symptoms
mild signs
- dry cough - worse at night with exercise or on exposure to triggers
- end- expiratory wheezes
- dyspnea
- chest tightness
- chronic allergic rhinitis with nasal congestions
severe signs
- severe dyspnea
- pulsus paradoxus
- hypoxemia
- accessory muscle use
- increase risk of pulmonary infection
Allergic bronchial asthma
-diagnosis (6)
- anamnesis, clinical examination
- SPT - differentiate non-allergic and allergic
- spirometry
- bronchial reversibility test - one with SABA and another without SABA
- blood tests: CBC, antibody testing, total IgE and allergen specific IgE
- methacholine challenge test - + if FEV1 reduced >20%
Allergic bronchial asthma
-treatment
- avoid triggers, allergen immunotherapy
- mild symptoms –> short acting beta 2 agonist (salbutamol)
- exercise induced asthma –> short acting beta 2 agonist prior to exercise
- asthma exacerbations –> albuterol, steroids, theophylline, humidified O2, magnesium, anti-cholinergics
Allergic bronchial asthma
-medications for symptomatic treatment (6)
- Beta - 2 - agonists - bronchodilators
- Inhaled corticosteroids (inhibit transcription factors) decrease expression of pro-inflammatory genes)
- Leukotriene receptor antagonists (decrease bronchoconstriction and inflammation)
- Muscarinic antagonists (bronchodilation)
- Methyxanthines (phosphodiesterase inhibitor –> anti-inflammatory and mild bronchodilatory effect)
- Biologic agents
Urticaria
-definition
-wheal and flare reaction initiated at level of small venules of skin
- pruritic, erythematous transient superficial swelling - wheal +/- angioedema
- mast cell degranulation and histamine liberation = local vasodilation (erythema) + vascular permeability (edema) + fibrin deposition + inflammatory cells infiltration + pruritus
Urticaria
-classification
Acute (< 6 weeks)
- all ages, abrupt onset, pruritic and widespread, angioedema
- fever, malaise (depend on the cause)
- causes: viral infection, drugs, foods, vaccines
- treatment: adrenaline, anti H1, short oral GCS
Chronic (daily urticaria eruptions >6 weeks)
Vascular urticaria
-causes: idiopathic, CT diseases, hepatitis
-labs: complement scree, ESR, CRP, XR, ECG
-treatment: anti H1 are not effective!
Physical urticaria
-symptomatic dermographism: pruritus and red wheals aggravated by scratching, rubbing. No angioedema (mucus membrane is not affected), low dose antihistamines for treatment
-delayed pressure urticaria: swelling lasts for a long time, often tender and painful, anti-histamines are not effective, standardized 5kg test for diagnosis
Urticaria
-subtypes of chronic physical urticaria
-cholinergic urticaria: cause is unknown, treatment with antihistamines and anabolic steroids
- ordinary chronic urticaria: autoimmune/ idiopathic, angioedema + physical urticaria + functional thyroid disease,
labs: CBC + differential WBC + ESR + CRP + thyroid function + thyroid auto-ab
treatment: antihistamines, GCS, cyclosporine, LTRA
-contact urticaria: substance causes local wheal and flare within minutes of skin contact
Atopic dermatitis
-symptoms
Infantile and childhood type
- “wet forms” - vesicles, erosions
- face, trunk, extensor surfaces of arms/legs
Childhood, adolescent and adult type
- “dry forms” - papules, lichenification, excoriations
- face, lateral aspects of neck, nuchal region, flexor surfaces of arms/legs
Atopic diathesis
Pruritus
