Urticaria

Which of the following would NOT be useful in the treatment of urticaria? A. Oral hydroxyzine B. Oral prednisolone C. Mupirocin ointment D. Oral doxepin

C. Mupirocin ointment Mupirocin ointment has no role in the treatment of urticaria. Oral Doxepin is a tricyclic antidepressant with potent antihistaminic properties. Useful in treating acute and chronic urticaria. Oral prednisolone is useful in suppressing acute and chronic urticaria. A H1-antihistamine, Oral hydroxyzine is used as initial therapy for acute urticaria.

What is direct mast cell activation?

Certain drugs, foods, and plants can cause urticaria due to mast cell degranulation through a non-IgE-mediated mechanism. The most frequently implicated are narcotics, muscle relaxants, vancomycin, and radiocontrast media. Some berries and nettle plants are examples of plants and plant foods that cause direct mast cell activation.

What are common causes of urticaria?

Common causes of new-onset urticaria include infections; allergic reactions to medications, foods, or insect stings and bites; reactions to medications that cause nonallergic mast cell activation (eg, narcotics); and ingestion of nonsteroidal anti-inflammatory drugs (NSAIDs).

All of the following statements about urticaria are correct except A. Individual lesion usually last for less than 24 hours B. Can be triggered by exercise C. Dermatographism is caused by pressure D. Chronic urticaria is urticaria lasting for more than 3 months

D. Chronic urticaria is urticaria lasting for more than 3 months Chronic urticaria is urticaria lasting for more than 6 weeks. All of the other statements are true.

The drug of choice for cold-induced urticaria is A. Verapamil B. Cimetidine C. Diphenhydramine D. Cyproheptadine E. Hydroxyzine

D. Cyproheptadine Urticaria is defined as an erythematous, pruritic rash that is often raised and occurs as discrete wheals and hives. The condition affects approximately 20% of the population. The rash involves the superficial layers of the skin. The center of the wheal is usually pale, and the rash blanches with pressure. Involvement of the deeper layers is referred to as angioedema. The causes include allergen exposure; heat, cold, or sunlight exposure; and trauma. In many cases, a cause is never detected. The response is thought to be mediated by an IgE antibody. Those affected by cold may have cryoglobulins or cryofibrinogen, which become activated. In extreme cases, bronchoconstriction and anaphylaxis can occur. Unfortunately, an underlying cause is identified in only approximately 20% of cases. Treatment involves avoiding factors that trigger the response. Other treatment involves the use of antihistamine (H1) medications and histamine blockers (H2) such as cimetidine. Doxepin may also be beneficial. The drug of choice for cold-induced urticaria is cyproheptadine. Other causes of urticaria include medication use, malignancy, endocrinopathies, autoimmune diseases.

What is the role of glucocorticoids in treating urticaria?

Glucocorticoids do not appear to be necessary for isolated urticaria. However, a brief course (ie, usually a week or less) of systemic glucocorticoids may be added to antihistamine therapy for patients with prominent angioedema or if symptoms persist beyond a few days. Glucocorticoids do not inhibit mast cell degranulation but may act by suppressing a variety of contributing inflammatory mechanisms. -Adults: prednisone -Children: prednisolone Antihistamine therapy should be continued during and after the course of glucocorticoids because some patients experience an exacerbation as the glucocorticoids are tapered or discontinued. Our approach is to treat all patients with H1 antihistamines, adding H2 antihistamines for more severe symptoms and reserving oral glucocorticoids for those patients with prominent angioedema or persistent symptoms despite antihistamines.

What are IgE-mediated allergic reactions?

Immunoglobulin E (IgE)-mediated, type I immediate allergic reactions often involve urticaria. Medications - The antibiotics most frequently implicated in causing IgE-mediated urticaria include beta-lactams (penicillins and cephalosporins). Latex - Occupational, recreational, dental, or surgical exposure to latex may cause urticaria, angioedema, asthma, or anaphylaxis in susceptible individuals. Foods and certain food additives - Allergic reactions to foods can cause urticaria, typically within 30 minutes of ingestion. Milk, eggs, peanuts, tree nuts, soy, and wheat are the most common foods to cause generalized urticaria in children.

How is urticaria managed?

Initial treatment of new-onset urticaria (with or without angioedema) should focus on the short-term relief of pruritus and angioedema, if present. Approximately two-thirds of cases of new-onset urticaria will be self-limited and resolve spontaneously.

What differential diagnoses should be considered when evaluating a patient for urticaria?

Nonpruritic conditions -Viral exanthems -Auriculotemporal syndrome -Sweet syndrome Pruritic conditions -Atopic dermatitis -Contact dermaitis -Drug eruptions -Insect bites -Bullous pemphigoid -Erythema multiforme minor -Plant-induced reactions

How do NSAIDs lead to urticaria?

Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, naproxen sodium, and others, can trigger urticaria and/or angioedema by two distinct mechanisms: Pseudoallergic/pharmacologic - NSAIDs cause urticaria in some individuals, presumably due to underlying abnormalities in arachidonic acid metabolism. Allergic - A specific NSAID can also cause acute urticaria in patients who are allergic to that one agent..

Why are first-generation antihistamines not used?

The first-generation antihistamines include diphenhydramine, chlorpheniramine, hydroxyzine, and others. These agents are lipophilic and readily cross the blood-brain barrier, causing sedating and anticholinergic side effects that may be dose-limiting in some patients. Significant sedation and impairment of performance (eg, fine motor skills, driving skills, and reaction times) occur in more than 20 percent of patients. Anticholinergic side effects include dry mouth, diplopia, blurred vision, urinary retention, or vaginal dryness. Patients should be warned specifically about these adverse effects. Despite these adverse effects, patients at low risk of complications (eg, young, healthy patients) may find a sedating H1 antihistamine at bedtime helpful, especially when combined with a nonsedating H1 antihistamine during the day. Agents: -Diphenhydramine (Benadryl) -Hydroxyzine (Vistaril)

What is first-line therapy for urticaria?

The newer, second-generation H1 antihistamines are recommended as first-line therapy by published guidelines from both allergy and dermatology expert panels. These drugs are minimally sedating, are essentially free of the anticholinergic effects that can complicate use of first-generation agents, have few significant drug-drug interactions, and require less frequent dosing compared with first-generation agents. Agents: -Cetirizine (Zyrtect) -Levocetirizine (Xyzal) -Loratidine (Claritin) -Desloratadine (Clarinex) -Fexofenadine (Aller-ease) Our approach is to treat all patients with H1 antihistamines, adding H2 antihistamines for more severe symptoms and reserving oral glucocorticoids for those patients with prominent angioedema or persistent symptoms despite antihistamines.

How is urticaria categorized?

Urticaria (with or without angioedema) is commonly categorized by its chronicity: Acute urticaria — Urticaria is considered acute when it has been present for less than six weeks. Chronic urticaria — Urticaria is considered chronic when it is recurrent, with signs and symptoms recurring most days of the week, for six weeks or longer. More than two-thirds of cases of new-onset urticaria prove to be self-limited.

What is the epidemiology of urticaria?

Urticaria affects up to 20 percent of the population at some point in their lives and occurs across the age spectrum.

How is urticaria diagnosed?

Urticaria is diagnosed clinically, based upon a detailed history and physical examination confirming the presence of characteristic skin lesions. -Lesions should be visualized directly in order to make the diagnosis with certainty, since the term "hives" is used nonspecifically by patients. Limit lab testing according to clinical history and indication. Skin or IgE testing should be limited to specific history of provoking allergen.

What is the pathophysiology of urticaria?

Urticaria is mediated by cutaneous mast cells in the superficial dermis.

What is urticaria?

Urticaria, or hives (sometimes referred to as welts or wheals), is a common disorder, with a prevalence of approximately 20 percent in the general population.

How does urticaria manifest clinically?

Urticarial lesions are circumscribed, raised, erythematous plaques, often with central pallor. Lesions may be round, oval, or serpiginous in shape and vary in size from less than 1 centimeter to several centimeters in diameter. They are intensely itchy. Pruritus may disrupt work, school, or sleep. Symptoms often seem most severe at night. Individual lesions are transient, usually appearing and enlarging over the course of minutes to hours and then disappearing within 24 hours. (+) Darier's sign: localized urticaria appearing where the skin is rubbed (histamine release).