From the Guidelines
The initial workup for a patient with hives of unknown origin should include a thorough history and physical examination, focusing on potential triggers such as medications, foods, infections, or environmental exposures, as recommended by the most recent guidelines 1. The workup should prioritize identifying potential causes of the hives, such as allergic reactions, infections, or autoimmune disorders.
- A detailed medical history should be taken to identify potential triggers, including recent medication use, food consumption, or exposure to environmental allergens.
- A physical examination should be performed to assess the severity of the hives and look for any other signs of allergic reaction, such as angioedema or respiratory distress. First-line treatment consists of non-sedating H1 antihistamines like cetirizine 10mg daily, loratadine 10mg daily, or fexofenadine 180mg daily, as these have been shown to be effective in reducing symptoms of hives 1.
- For inadequate response, the antihistamine dose can be increased up to four times the standard dose.
- For severe or refractory cases, add a short course of oral corticosteroids such as prednisone 40-60mg daily for 3-5 days, as recommended by recent guidelines 1. Acute severe reactions with angioedema or respiratory symptoms require epinephrine (0.3-0.5mg IM for adults), as this is a life-threatening emergency that requires immediate treatment 1.
- Patients should be advised to avoid identified triggers, keep a symptom diary to help identify patterns, and seek immediate medical attention if they develop difficulty breathing, throat tightness, or other signs of anaphylaxis.
- Referral to an allergist-immunologist may be necessary for further evaluation and management, particularly if the cause of the hives is unclear or if the patient has a history of severe allergic reactions 1.
From the FDA Drug Label
5 Allergic States Control of severe or incapacitating allergic conditions intractable to adequate trials of conventional treatment: Seasonal or perennial allergic rhinitis Bronchial asthma Contact dermatitis Atopic dermatitis Serum sickness Drug hypersensitivity reactions
The initial workup and treatment for a patient presenting with hives of unknown origin may involve:
- Identifying and removing the potential allergen or trigger
- Considering drug hypersensitivity reactions as a possible cause
- Using medications such as prednisone (PO) 2 for control of severe or incapacitating allergic conditions.
- A thorough medical history, physical examination, and laboratory tests to rule out underlying conditions that may be contributing to the hives.
From the Research
Initial Workup for Hives of Unknown Origin
The initial workup for a patient presenting with hives of unknown origin involves a thorough clinical history to identify potential causes, as urticaria is very often idiopathic 3.
Classification and Investigation
Classification and investigation of urticaria are crucial, and the clinical history is most important when attempting to identify potential causes 3.
Treatment Approach
The treatment of chronic spontaneous urticaria begins with antihistamines, typically second-generation, relatively non-sedating H₁-receptor blockers, which can be used at higher than licensed doses if normal doses fail to control the disease 4, 5.
Treatment Algorithm
The treatment algorithm for urticaria follows a standardized approach, with the following steps:
- Antihistamines as the first-line treatment 6, 4, 5
- Addition of glucocorticosteroids for short periods if antihistamines fail to control symptoms 6
- Consideration of omalizumab for antihistamine-refractory patients 4, 5
- Cyclosporine as an alternative for patients unresponsive to antihistamines and omalizumab 5
- Brief courses of corticosteroids for severe exacerbations, but not for chronic use due to cumulative toxicity 5
Referral to a Specialist
Patients not responsive to initial treatment steps should be referred to an urticaria specialist for further evaluation and treatment 7.
Key Considerations
It is essential to identify patients with severe urticaria, as it is a distressing and disabling condition, and to exclude inducible stimuli causing hives using specific provocation testing 3, 7.