Title: GZ / The Grenz Zone Season 2 / 27 Urticaria
Tags: GZ DermnetNZ

Q: Urticaria can be classified into [...], intermittent, and [...] forms
A: acute; chronic
Back Extra: Commonly known as "hives". Affects 10-20% of population. Can present at any age

Q: Acute urticaria lasts [how many weeks] and does not necessarily occur on a daily basis
A: < 6 weeks

Q: Some triggers of acute urticaria are [broad category], [broad category], physical triggers, and [...]
A: bugs; drugs; food
Back Extra: Bugs: insect stings and infections (Upper respiratory infections are the most common infectious cause of urticaria)
Drugs: ACE inhibitors, NSAIDs, opioids
Physical triggers: dermatographism, cold urticaria, delayed pressure, cholinergic, adrenergic, heat, solar, aquagenic, vibrational
Foods: WEMPS (wheat, eggs, milk, peanuts, soy)

Q: What are 2 reasons why cold urticaria can be dangerous?
Swimming in cold water can cause [...] leading to hypotension, syncope, and drowning
There are secondary cold contact urticaria's due to things like [...] and/or [...]
A: massive histamine release; cryoglobulins; Hepatitis B & C
Back Extra: Pt's should be counseled against swimming in cold bodies of water

Q: Clinically, urticaria presents as [...] of the dermis
A: recurrent papular swellings
Back Extra: Can be associated with angioedema typically affecting the lips and periorbital areas

Q: On histology, urticaria presents with limited epidermal change, [...], perivascular/interstitial mixed infiltrate with neutrophils
A: superficial dermal edema
Back Extra: If vascular damage is seen = urticarial vasculitis

Q: Solar urticaria occurs within minutes of exposure to visible light, [...], and [...]
A: UVA; UVB
Back Extra: Common boards question

Q: The key question to ask when trying to diagnose urticaria is [...]
A: duration of lesion
Back Extra: Inducible: a few hours
Spontaneous: <24 hrs
Urticarial vasculitis: >24 hrs
Make sure to assess for angioedema, anaphylaxis, triggers (e.g. bugs, drugs, physical, food)

What are some H&P findings that would make you consider urticarial vasculitis?
1. Hives lasting >24 hrs
2. Painful > pruritic
3. Purpura
4. Systemic sxs

Q: Treatment of urticaria includes address triggers and [...]
A: 2nd generation antihistamines
Back Extra: 2nd gen antihistamines (e.g. Loratadine, Fexofenadine, Cetirizine)
If minimal improvement, consider increasing dose, adding another 2nd gen antihistamine, H2 receptor blocker, leukotriene blocker, or 1st gen antihistamine
Severe cases: systemic steroids, UV tx, doxepin, cyclosporine, or Omalizumab

Q: What are the 2 types of contact urticaria?
[...]
A: immunologic or non-immunologic
Back Extra: Immunologic: type 1 hypersensitivity reaction (e.g. latex, meats, potatoes, etc.)
Non-immunologic: triggered by jellyfish stings or stinging nettles

Q: Chronic urticaria is defined as nearly daily or daily episodes of urticaria for [time period]
A: > 6 weeks
Back Extra: Can be divided into inducible and spontaneous forms

The 30% rule sum up the 4 unique features of chronic urticaria. They are:
30% associated with autoantibodies to mast cells' IgE receptor or IgE itself
30% of pt's have thyroid auto-antibodies
30% are exacerbated by aspirin
30% resolve within 5 years
Back Extra: Pearl: Thyroid disease is NOT the only associated autoimmune condition. Can be associated with type 1 DM, Lupus, Rheumatoid Arthritis
Pearl: 50% of pt's display anxiety, depression, or somatoform disease

Q: Dermatographism presents as a [...] that forms within minutes of stroking or scratching the skin
A: wheal

Q: Cold urticaria presents during the [...] phase after cold air/water exposure
A: rewarming
Back Extra: Counsel patients against swimming in cold bodies of water due to massive histamine release → hypotension, syncope, and drowning

Q: Different types of chronic [...] urticaria (physical triggers) are dermatographism, cold urticaria, delayed pressure, cholingeric, adrenergic, heat, solar, aquagenic, and vibrational
A: inducible
Back Extra: Dermatographism: "skin writing" forms wheal within minutes
Cold urticaria: during rewarming phase after cold air/water exposure
Delayed pressure: may be delayed by 12 hours (e.g. tight waistband)
Cholingeric: sweating and exercise increase core body temp
Adrenergic: blanched vasoconstricted halo occurs after stress-induced release of adrenaline
Heat: within minutes of contact with heat
Solar: within minutes of exposure to all types of light (e.g. visible light, UVA, UVB)
Aquagenic: contact with water of ANY temp
Vibrational: lawnmowers, motorcycles, jackhammer, etc.