If you have recurring hives or episodes of swelling for more than six weeks, chronic spontaneous urticaria (CSU) may be the explanation. The diagnosis is usually based on the pattern of symptoms and a clinical assessment—not on finding a particular food or environmental allergy. Treatment typically starts with a newer, less-sedating antihistamine and may step up to omalizumab or specialist care if symptoms remain poorly controlled.
What chronic spontaneous urticaria means
Urticaria is the medical term for hives, also called wheals. CSU describes recurring itchy hives, angioedema (deeper swelling), or both for more than six weeks without a definite, consistent external trigger. “Spontaneous” does not mean symptoms are imagined or that nothing is happening: CSU involves immune activity in the skin, but the precise cause is often not identified.
Some people have swelling without obvious hives. Because other conditions can also cause wheals or swelling, a clinician will consider the symptom pattern, your medical history, medicines, and possible alternatives. This may include chronic inducible urticaria, where symptoms follow a reproducible stimulus, or other conditions that can resemble CSU.
How chronic spontaneous urticaria is diagnosed
There is no single test that confirms CSU. A clinician generally makes the diagnosis from recurring symptoms lasting longer than six weeks, while checking for clues that point to a different explanation. Photos of a rash that has faded before your appointment, and a brief record of when symptoms and swelling occur, can help describe the pattern.
Extensive allergy testing is often unhelpful when there is no clear link between symptoms and a particular exposure. CSU usually does not behave like an immediate allergy to one specific food or substance, and a positive result on a broad allergy panel does not by itself show that the item causes your hives. Tests may be useful when your history suggests a specific allergy or another condition; your clinician can decide whether targeted tests or basic blood work are appropriate.
If symptoms reliably follow a particular exposure, that history matters. For instance, reactions after mammalian meat can sometimes involve alpha-gal allergy, which is distinct from CSU; you can read more about delayed alpha-gal symptoms.
Chronic hives treatment usually steps up gradually
The aim is to control itch, hives, and swelling while limiting unnecessary treatment. International guidelines support a stepwise approach:
- Start with a second-generation H1 antihistamine. These medicines are generally less sedating than older antihistamines. If symptoms persist, a clinician may recommend increasing the dose, up to four times the usual licensed dose. That higher dosing may be off-label, depending on where you live, so do not increase your dose without medical guidance.
- Consider omalizumab if symptoms remain uncontrolled. Omalizumab (Xolair) is an injectable biologic that may be added when antihistamines are not enough. It helps many people, but it does not guarantee complete control. In a 2026 analysis of the international CURE registry, researchers assessed treatment and symptom-control changes over six months. Among adults whose treatment moved from an antihistamine to omalizumab, 28.4% achieved a complete response. This was an observational registry analysis, not a trial comparing treatments, and it shows that some people need further help.
- Ask a specialist about options if symptoms persist. A specialist may review the diagnosis and treatment plan. Ciclosporin is one possible later treatment, but it is off-label for urticaria and requires medical supervision. Treatment choice depends on your situation and local guidance.
Omalizumab’s approved dosing differs by region. The United States label allows 150 mg or 300 mg every four weeks for CSU; the European licensed dose described in clinical literature is 300 mg every four weeks. Eligibility, availability, and funding can also vary. Check current local product information with your clinician, especially in Australia or other regions where those details are not established here.
When swelling or breathing symptoms are an emergency
Call your local emergency number for difficulty breathing, throat or tongue swelling, fainting, or rapidly worsening symptoms. These can signal a serious reaction and need urgent assessment. Do not wait for a routine appointment. For swelling without breathing problems, seek prompt medical advice, particularly if it is new, severe, or not like your usual episodes.
CSU can fluctuate, so control may change over time. If treatment is not helping enough, tell your clinician how often symptoms occur and how they affect sleep or daily life; that information can guide reassessment and the next treatment step.
