Chronic Spontaneous Urticaria

What Is Chronic Spontaneous Urticaria?

Chronic spontaneous urticaria (CSU) is a condition in which itchy raised welts, swelling beneath the skin, or both occur repeatedly for more than six weeks without a consistent external trigger. Individual hives usually fade within 24 hours, although new ones may continue to appear.

CSU is not contagious and is usually not caused by a food allergy. The condition can significantly disrupt sleep, concentration, work, and emotional wellbeing.

What Causes Chronic Spontaneous Urticaria?

In many cases, CSU is driven by autoimmune activation of mast cells, which release histamine and other inflammatory mediators in the skin. The exact initiating cause often cannot be identified.

Heat, pressure, stress, infection, alcohol, and certain medicines may worsen symptoms without being the underlying cause. Nonsteroidal anti-inflammatory drugs can aggravate hives in some patients.

Diagnosis

Diagnosis is based primarily on the history and appearance of typical hives or angioedema lasting more than six weeks. Extensive allergy testing is usually unnecessary unless the history points to a specific trigger; limited blood tests may be used to look for inflammation or associated thyroid disease.

Treatment Options

Second-generation, non-sedating H1 antihistamines are first-line treatment and may be adjusted under medical supervision. Trigger avoidance is recommended only when a reproducible aggravating factor has been identified.

For symptoms that remain uncontrolled, biologic therapy such as omalizumab or other specialist treatments may be considered. Short courses of oral corticosteroids are sometimes used for severe flares but are not suitable as routine long-term therapy.

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Living With Chronic Spontaneous Urticaria

Photographs and a symptom diary can help document episodes that disappear before an appointment. Patients may record hive frequency, swelling, medication use, infections, menstrual patterns, pressure or heat exposure, and effects on sleep and daily function.

Loose clothing, cool compresses, fragrance-free skin products, and avoiding known aggravators may provide additional comfort. Patients should review painkillers and other medicines with their clinician rather than stopping necessary treatment independently.

When to Seek Emergency Care

Call emergency services immediately if swelling affects the tongue or throat, breathing becomes difficult, wheezing develops, the voice changes, faintness occurs, or symptoms suggest anaphylaxis. Isolated lip or eyelid swelling without breathing symptoms still requires prompt medical advice if severe or progressive.

Prognosis

CSU often resolves spontaneously over time, although the duration is unpredictable and symptoms may recur. Most patients can achieve good control with stepwise treatment even when the underlying cause remains unknown.

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