Urticaria

Define Urticaria

(Hives) is a vascular reaction of the skin characterized by wheals surrounded by a red halo or flare (area of erythema)

What is Anaphylaxis fist-line treatment?

- IM Epinephrine, repeating every 10-20 minutes as necessary - IV fluids - Oxygen

Referral to a dermatologist and biopsy should be performed in patients with one or more of the following features:

- Individual lesions that persist beyond 48 hours, are painful or burning rather than pruritic, or have accompanying petechial characteristics - Systemic symptoms - Lack of response to antihistamines - Lesions that leave pigmentation changes upon resolution

Describe the Urticaria clinical findings

- Lesions typically appear over the course of minutes, enlarge, and then disappear within hours - Individual wheals rarely last >12hrs - Surrounding erythema will blanch with pressure - Urticaria may be acute or chronic • Acute = new onset urticaria < 6 weeks • Chronic = recurrent urticaria > 6 weeks - Most urticaria is acute and resolves

What medications are a common cause of urticaria and angioedema?

- Penicillin and related antibiotics are common via the IgE-mediated mechanism - Aspirin is a common cause via a non-IgE-mediated mechanism - 30% of chronic urticaria is exacerbated by aspirin/NSAID use

What is the etiology of Chronic Urticaria?

-Idiopathic: over 50% of chronic urticaria -Physical urticarias: caused by pressure, cold, heat, water (aquagenic), sunlight (solar), vibration, heat, emotions, and exercise -Autoimmune Urticaria: possibly a third or more of patients with chronic urticaria -Other: infections, ingestions, medications

Describe Dermatographism

-Most common form of physical urticaria -Sharply localized edema or wheal within seconds to minutes after the skin has been rubbed

How can you distinguish Urticaria Multiforme from Erythema Multiform

-We can distinguish from erythema multiforme (EM) because in EM, individual lesions are fixed for at least 7 days. Also, urticaria multiforme improves with antihistamines

A 23 year old woman has had chronic urticaria for 2 years and is very frustrated. She has tried several second-generation antihistamines with only partial relief. She is concerned about sedation during the day. Which of the following would likely be helpful to add to her regimen?

A first-generation antihistamine taken in the evening

Describe Urticaria Multiforme

A subset of pediatric urticaria with larger polycyclic or annular lesions with dusky and ecchymotic centers along with acral edema.

What part of the body is most affected by angioedema?

Affects the face or a portion of an extremity. May be painful or burning, but not usually pruritic Involvement of the lips, cheeks, and periorbital areas is common, but angioedema also may affect the tongue, pharynx, larynx and bowels

Describe the pathophysiology of Immunologic Urticaria

An antigen binds to IgE on the mast cell surface causing degranulation, which results in release of histamine Histamine binds to H1 and H2 receptors to cause arteriolar dilatation, venous constriction and increased capillary permeability, causing swelling and itch.

A 25 year old woman notes a 2 month history of itchy, intermittent welts that appear all over her body, with individual lesions lasting about a day. She notes that topical hydrocortisone 1% cream does not offer much relief. What is the best first line therapy for her condition.

Antihistamines

If you suspect anaphylaxis, what should be your next step?

Assess ABC's (Airway, Breathing, Circulation) then call 911

What are some similarities between Urticaria and Angioedema?

Both may occur in any location together or individually. Angioedema and/or urticaria may be the cutaneous presentation of anaphylaxis, so assessment of the respiratory and cardiovascular systems is vital

How do you manage patients with chronic urticaria?

Daily oral 2nd gen. H1 antihistamine = 1st line Tx

A 9 year old boy eats ice cream topped with peanuts and begins to develop erythematous wheals on the lips, face and trunk. He had slight wheezing during the episode, but was not taken to the hospital and felt better within an hour. The family presents for treatment options several weeks later. Which of the following is recommended?

Epinephrine pen with sufficient instruction on how and when to use it

There are several medications used to treat urticaria, including antihistamines. Which of the following is considered the most potent treatment for urticaria?

First-generation antihistamines

A 62 year old man has been struggling with urticaria for over 3 years. He has been tested several times for allergies, but all have been negative. What is the most common cause for chronic urticaria?

Idiopathic

What are the common causes of Acute Urticaria?

Idiopathic Infection - Upper respiratory, streptococcal infections, helminths - Most common cause of urticaria in children is viral illness Food reactions - Shellfish, nuts, fruit, etc. Drug reactions IV administration - Blood products, contrast agents

Describe the pathophysiology of Non-Immunologic Urticaria

It is not dependent on the binding of IgE receptors Aspirin may induce histamine release through a pharmacologic mechanism where its effect on arachidonic acid metabolism causes a release of histamine from mast cells. Physical stimuli may induce histamine release through direct mast cell degranulation.

A 32-year-old woman has had hives for 8 weeks. She has not started any new medications. Her hives are not painful and do not leave behind any pigmentation or other marks when individual resolve (within 24 hours). She has not had respiratory symptoms or lip or tongue swelling. She is frustrated with the amount of pruritus, but does not want to take any medications that make her "sleepy." Which of the following medications would you recommend?

Loratadine

What patient usually get allergy testing done?

Patients with acute uricaria

Cardinal symptom of urticaria

Pruritus (itch)

If someone has Urticaria, what ROS is essential to review?

Respiratory and skin exam, due to the possibility of anaphylaxis symptoms. No lab test required

What causes urticaria?

Swelling of the upper dermis

A 27-year-old woman presents to clinic with one week of "hives" that have appeared on her neck, trunk, and proximal extremities (its urticaria bro). They are very pruritic, and each lesion resolves within about a day. What is the next best step in management?

Testing is not necessary at this time

What is the major effector cell in Urticaria?

The mast cell

In patients with idiopathic chronic urticaria, there is a rate of spontaneous remission at one year of _________

approximately 30 to 50 percent

Describe the pathogenic mechanism of angioedema

caused by the same pathogenic mechanisms as urticaria, but the pathology is in the deep dermis and subcutaneous tissue and swelling is the major manifestation

If a physical urticaria is suspected, a _____________________ test with the respective trigger may be performed

challenge test