Clinical Medicine: Intro to Allergic Disease Flashcards
Etiology of anaphylaxis
IgE mediated. Caused by: 1. food 2. Pollen 3. Insect stings (venom) 4. Latex 5. Drugs Nonimmunolgic: (mast cell degranulation, but not IgE mediated) 1. Exercise 2. Cold 3. Heat (sunlight/UV)
Clinical presentation of anaphylaxis (5-30min)
- CNS - lightheadedness, LOC, confusion, headache, anxiety
- Resp - SOB, Wheezes, pain with swallowing, cough, bronchodilation.
- GI - Cramping, diarrhea, vomitting
- Skin - hives, itchiness, flushing (90% of pts)
- Vascular - Hypotension, swelling, smooth muscle contraction
- Eyes - Swelling of conjuctiva
Category of RXN of anaphylaxis
Type I
Etiology of autoimmune hemolytic anemia
1/2 of cases idiopathic
- may also be associated with systemic lupus erythematous
Chronic lymphocytic leukemia
lymphomas. Caused by antibody induced hemolysis (destruction of RBCs) IgG or IgM mediated
Clinical presentation of hemolytic anemia
- May be asymptomatic
- Life threatening
- Looks like other anemias
- Fatigue, dyspnea
- Angina or HF
- Jaundice and splenomegaly may be present
Category of RXN of hemolytic anemia
Type II
Etiology of post streptococcal glomerulonephritis (PSGN)
Caused by prior infection with group A beta-hemolytic streptococcus (immune complex hypersensitivity). Complexes get trapped in glomeruli that causes an inflammatory reaction.
Who presents with PSGN most commonly
2-6yo with hx of pharyngitis(cold climate) and rash-impetigo (warm climate)
Clinical presentation of PSGN
- Most children asymptomatic
- Headache, malaise
- Anorexia, nausea, vomiting
- Flank/back pain - red urine
- Oligouria
- Elevated BP/edema
Category of RXN of PSGN
Type III
Etiology of serum sickness
Caused by antitoxins, antivenins, streptokinase, vaccines, insects. This then induces an antibody response and the formation of an immune complex. Causes tissue damage and vasculitis
Clinical presentation of serum sickness
- Pruritic rash - maculopapular or urticarial (hives)
- High fever
- polyarthritis
Begins 7-10 days after exposure
Usually goes away but could progress to angioedema, nephritis
Category of RXN of serum sickness
Type III
Etiology of vasculitis
Immune complexes are trapped in vessel walls. Leads to vessel injury. Primary - unknown cause. Secondary - infectious cause
Clinical presentation of vasculitis
- Fever, night sweats
- Fatigue, anorexia, weight loss
- Arthalgia/arthritis
- alveolar hemorrhage
- Mesenteric ischemia
(some skin lesions - Palpable purpura - small vessels
Category of RXN of vasculitis
Type III
Types of vasculitis (classification)
- Small vessel - Henoch-schonlein
- Medium vessel - kawasaki disease
- Large vessel - Giant cell temporal arteritis
Etiology of contact dermatitis
- Sensitization to an antigen
- Allergic response after reexposure
Many causes - see chart in lecture notes pg 27
Clinical presentation of contact dermatitis
Primary = intense pruritis 1. Transient erythema 2. vesiculations 3. Excoriation/infection 4. Swelling with bullae Most common site is hands
Category of RXN of contact dermatitis
Type IV
Etiology of transplant rejection
Graft destruction caused by T cell-mediated reaction to allograft histocompatibility antigens
Clinical presentation of transplant rejection
Seen within days-few months post transplant
- Fever/chills
- Malaise
- Arthralgias
Category of RXN of transplant rejection
Type IV
What is the difference between anaphylaxis and anaphylactoid
- Anaphylaxis is mediated by IgE where as anaphylactoid is not
- Anaphylactoid can occur at 1st exposure, anaphylaxis cannot
- Skin test can only predict allergy in anaphylaxis
What is urticaria
Hives. A vascular reaction of the skin characterized by wheals surrounded by a red halo. PRURITUS!! is the main symptom.
What causes urticaria
Swelling of the upper dermis due to a mast cell reaction (IgE mediated) - can be secondary to anaphylaxis. Usually not longer than 12hrs.
(allergic rxn to food, worms, drugs -NSAIDS, penicillin, blood, IV contrast)
What is angioedema
Same manifestation as urticaria but it occurs in the deep dermis and subcutaneous tissue. Shows up as swelling more than wheals
Where is angioedema most commonly seen
Face and portion of an extremity. NOT pruritic. More painful or burning sensation. Seen in lips, cheeks, periorbital
What is hereditary angioedema (HAE)
Rare autosomal inherited blood disorder that causes swelling of face, extremities, genitals, GI tract and upper airway
What is acquired angioedema
Angioedema that occurs when there is a C1 inhibitor deficiency. C1 helps regulate the complement activation pathway. Result of allergy?
Etiology of allergic rhinitis
Caused by exposure to an airborne allergen in predisposed individuals (IgE response in addition to humoral and cytotoxic responses). IgE response, triggers mast cells (histamine) that migrate to the nasal epithelium.
Genetics, hygiene hypothesis, seasonal allergy
Clinical presentation of allergic rhinitis
- nasal congestion
- Rhinorrhea
- Sneezing
- Nasal Itching
- Pale or violet turbinates
- Conjunctival watering
- Postnasal drainage
Management of allergic rhinitis
- Intranasal corticosteroid sprays and systemic steroids
- Antihistamines - temporary/immediate relief
- Tailor the therapy to the individual
- Control environments - bed sheets, dust, clean
What is vasomotor rhinitis
Caused by an increased sensitivity of the vidian nerve and is the common cause of clear rhinorrhea in the elderly. Due to response of nasal stimuli (odors, scents, light)
Etiology of allergic conjunctivitis
Caused by seasonal allergens (usually hay fever related)
Clinical presentation of allergic conjunctivitis
Hyperemia and edema of the conjunctiva of the eye.
Will show up as red, itchy, swollen eyes
Management of allergic conjunctivitis
- Antihistamine
- Eye drops
- Air purifier
Clinical presentation of asthma
- Wheezing
- Dyspnea
- Chest tightness
- Cough
(other symptoms may include urticaria, angioedema, erythema)
What causes asthma
An IgE mediated response to an allergen. Could also be a non IgE mediated response such as smoke, or temp.
What is a food allergy
An adverse health effect arising from a specific immune response that occurs reproducibly after exposure to a given food
What are the common food allergies in children
Eggs, milk, and peanuts. Highest prevalence is in children with moderate to severe atopic dermatitis. (others include shellfish, tree nuts, soy, wheat,)
What are the common food allergies in adults
Fish, shellfish, peanuts, tree nuts, soybean, and some fruits
What is the difference between a food allergy and an adverse food reaction
Food allergies actually activate the immune system where as adverse reactions usually involve more of the body’s metabolic activities. Only 3-4 % of the adult population actually has a food allergy
What are IgE -mediated food allergies (or mixed IgE)
- Immediate GI anaphylaxis
- eosinophilic esophagitis/gastroenteritis
- Oral allergy syndrome
Clinical presentation (time frame) of IgE-mediated food allergies
- Occur within minutes-2hrs
2. Hives, flushing, facial angioedema, throat itching
Clinical presentation (time frame) of non IgE mediated or mixed disorders for food allergies
- Delayed onset of more than several hours
2. Similar symptoms as the IgE mediated reactions.
What does the CDC recommend for vaccines in all adults
- Seasonal influenza
- Td every 10 years
- Tdap once instead of Td
- Varicella
- MMR
- Other vaccines will be determine by other factors such as age, lifestyle job, etc