What is the diagnosis and treatment for acute urticaria (hives)?

From the Guidelines

Acute urticaria should be treated with non-sedating antihistamines such as cetirizine (10mg daily), loratadine (10mg daily), or fexofenadine (180mg daily) as first-line treatment, with the option to increase the dose up to four times the standard dose if necessary, as recommended by the most recent guidelines 1. For severe cases, a short course of oral corticosteroids like prednisone (40-60mg daily for 3-5 days) may be prescribed. Identifying and avoiding triggers is crucial for management; common triggers include certain foods, medications (especially NSAIDs and antibiotics), insect stings, latex, and physical factors like pressure or temperature changes. Some key points to consider in the management of acute urticaria include:

• The use of antihistamines, which can be effective in treating cutaneous signs and symptoms associated with anaphylaxis, but should not be administered before, or in place of, epinephrine 1.
• The role of glucocorticoids, which have a limited role in the acute management of anaphylaxis due to their slow onset of action and inability to reverse acute symptoms 1.
• The importance of identifying and avoiding triggers, as well as seeking immediate medical attention if experiencing symptoms of anaphylaxis such as difficulty breathing, throat tightness, or dizziness.
• The pathophysiology of acute urticaria, which involves the release of histamine and other inflammatory mediators from mast cells in the skin, causing local vasodilation, increased vascular permeability, and the characteristic wheals and flare reaction. It is also important to note that most cases of acute urticaria resolve spontaneously within days to weeks without long-term consequences. However, in some cases, acute urticaria can be a symptom of a more serious underlying condition, such as anaphylaxis, which requires immediate medical attention. In terms of specific treatment options, the choice of antihistamine and corticosteroid will depend on the individual patient's needs and medical history. For example, cetirizine may be a good option for patients who require a rapid onset of action, while fexofenadine may be a better choice for patients who require a longer duration of action. Overall, the management of acute urticaria requires a comprehensive approach that takes into account the patient's individual needs and medical history, as well as the latest evidence-based guidelines and recommendations.

From the Research

Definition and Classification of Urticaria

• Urticaria is a common skin condition characterized by intensely pruritic wheals, sometimes with edema of the subcutaneous or interstitial tissue 2
• It can be classified into spontaneous versus inducible types, with spontaneous urticaria further divided into acute and chronic forms 3

Causes and Triggers of Urticaria

• Urticaria is caused by immunoglobulin E- and non-immunoglobulin E-mediated release of histamine and other inflammatory mediators from mast cells and basophils 2
• Triggers may include drugs, infections, autoimmunity, and other factors, although in many cases the cause remains unknown 3, 2

Diagnosis of Urticaria

• Diagnosis is made clinically, with a thorough history and physical examination to identify potential triggers and rule out other conditions such as anaphylaxis 2
• Laboratory tests may be ordered in some cases, but are not typically necessary for acute urticaria 3, 2

Treatment of Acute Urticaria

• The mainstay of treatment is avoidance of triggers, if identified, and the use of antihistamines to relieve symptoms 2, 4
• Second-generation antihistamines such as loratadine and cetirizine are preferred due to their lower risk of sedation and anticholinergic side effects 4, 5
• The addition of corticosteroids to antihistamines may not provide significant benefit in acute urticaria, although more research is needed to confirm this 6

Treatment of Chronic Urticaria

• Treatment of chronic urticaria may involve higher doses of antihistamines, as well as the use of other medications such as omalizumab and cyclosporine in refractory cases 3, 2
• Non-pharmacotherapeutic measures such as prevention of skin drying and avoidance of hot showers and excessive sun exposure may also be helpful 3