Chronic Spontaneous Urticaria (CSU): Causes, Treatment Options, Why It Keeps Coming Back and What to Expect
By Dr Lim Tzyy Huei | Consultant Dermatologist, Pantai Hospital Batu Pahat, Johor, Malaysia
Do you frequently experience itchy, raised red patches on your skin that appear suddenly, disappear within hours, and then return again?
Some patients develop these rashes almost every day. Others may experience swelling around the eyelids, lips or face.
Despite avoiding certain foods, changing skincare products or taking allergy medications, the symptoms may continue for weeks or months.
This condition may be Chronic Spontaneous Urticaria (CSU), commonly known as chronic hives.
CSU can be frustrating because the symptoms often appear without an obvious trigger. However, with proper diagnosis and a structured treatment plan, most patients can achieve meaningful symptom control.
What Is Chronic Spontaneous Urticaria?
Urticaria, commonly known as hives, causes itchy, raised swellings on the skin called wheals.
These wheals may vary in size and shape. They can appear anywhere on the body, disappear and then develop in another location.
In typical urticaria, an individual wheal usually disappears within 24 hours without leaving a scar or permanent mark.
Urticaria is classified according to its duration:
Acute urticaria: Symptoms lasting up to six weeks.
Chronic urticaria: Recurrent symptoms lasting more than six weeks.
Chronic spontaneous urticaria refers to recurrent hives, swelling or both that develop without a consistent, identifiable external trigger.
Some patients also develop angioedema, which causes deeper swelling, commonly around the lips, eyelids, hands or feet.
Although CSU is usually not life-threatening, persistent itching, visible skin changes and unpredictable flare-ups can significantly affect sleep, daily activities and emotional well-being.
What Causes Chronic Spontaneous Urticaria?
One of the most common questions patients ask is:
"Doctor, what am I allergic to? Why do I keep getting hives?"
Interestingly, CSU is usually not caused by a conventional food allergy.
The condition involves abnormal activation of certain immune cells in the skin, particularly mast cells.
When mast cells are activated, they release histamine and other inflammatory substances, causing itching, redness, wheals and sometimes swelling.
In some patients, autoimmune mechanisms play an important role. The immune system may produce antibodies that contribute to mast cell activation.
However, the exact underlying mechanism may not always be identifiable.
This explains why patients can experience repeated episodes of hives even when they have not eaten anything unusual or changed their daily routine.
What Can Trigger or Worsen CSU?
Although CSU occurs spontaneously, certain factors may aggravate existing symptoms.
Common contributing factors include:
1. Emotional Stress
Stress does not necessarily cause CSU, but it can worsen itching and increase the frequency or intensity of flare-ups.
Some patients notice worsening symptoms during periods of emotional stress, poor sleep or physical exhaustion.
2. Infections
Viral infections and other illnesses may temporarily aggravate urticaria.
However, this does not mean that every patient with CSU has an underlying infection requiring treatment.
3. Heat and Sweating
Hot weather, hot showers and excessive sweating can worsen symptoms in some patients.
This may be particularly relevant in Malaysia's hot and humid climate.
4. Certain Medications
Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and aspirin, may worsen urticaria in susceptible individuals.
Patients should inform their doctor if they notice worsening symptoms after taking particular medications.
Do not discontinue prescribed medication without medical advice.
5. Alcohol and Other Individual Aggravating Factors
Alcohol, pressure from tight clothing and other individual factors may aggravate symptoms in some patients.
However, not everyone with CSU has the same triggers.
The aim is to identify genuine aggravating factors rather than unnecessarily avoiding large groups of foods or activities.
Is Chronic Spontaneous Urticaria a Food Allergy?
This is a common misunderstanding.
Unlike immediate food allergies, which typically cause symptoms shortly after exposure to a specific food, CSU often occurs independently of food intake.
Many patients undergo extensive food allergy testing or start restrictive diets, hoping to find a particular food responsible for their symptoms.
However, routine food allergy testing is usually not necessary unless the patient's history suggests a reproducible allergic reaction.
Unnecessary food restriction may cause additional stress and nutritional imbalance without improving the condition.
If a specific food consistently causes symptoms shortly after ingestion, further assessment may be appropriate.
Do I Need Allergy Tests or Blood Tests?
The diagnosis of CSU is primarily based on a detailed medical history and examination.
Your dermatologist may ask about:
How long the hives have been occurring
Whether individual wheals disappear within 24 hours
The frequency and severity of symptoms
Associated swelling of the lips or eyelids
Possible medication-related triggers
Other symptoms or underlying medical conditions
Selected blood tests may be recommended, including a full blood count and inflammatory markers.
In specialist care, thyroid autoantibodies and total IgE may sometimes provide additional information about the underlying disease mechanisms and likely treatment response.
However, a normal total IgE level does not exclude CSU, and an elevated IgE level does not automatically mean that food allergy is responsible.
Extensive investigations are generally unnecessary unless the history or examination suggests another condition.
What Are the Treatment Options for CSU?
Treatment aims to reduce itching, prevent new wheals and swelling, improve sleep and quality of life, and achieve good long-term disease control.
Treatment is usually introduced in a stepwise manner depending on symptom severity and response.
1. Second-Generation Antihistamines
Modern, second-generation antihistamines are generally the first-line treatment for CSU.
Common examples include:
Fexofenadine
Bilastine
Cetirizine
Levocetirizine
Desloratadine
Rupatadine
These medications block the effects of histamine and help reduce itching and wheal formation.
Unlike older antihistamines, many second-generation antihistamines are less likely to cause significant drowsiness.
For patients with frequent symptoms, regular daily treatment is often more effective than taking medication only when itching becomes severe.
What if the usual antihistamine dose does not work?
Some patients require higher doses to achieve adequate symptom control.
Under medical supervision, the dose of a second-generation antihistamine may be increased up to four times the standard dose in selected patients.
This is a recognised guideline-supported approach, although higher-than-licensed dosing is generally off-label.
Patients should not increase their medication dosage without discussing it with their treating doctor.
2. Omalizumab (Xolair) – Targeted Biologic Treatment
For patients whose CSU remains uncontrolled despite appropriately increased antihistamine treatment, omalizumab may be recommended.
Omalizumab is a targeted biologic medication that binds to immunoglobulin E (IgE), helping reduce mast cell activation.
It is administered by subcutaneous injection, commonly at four-week intervals.
What can patients expect?
Many patients experience a significant reduction in itching, hives and swelling.
Some patients improve within the first few weeks, while others require several months before the full benefit becomes apparent.
Treatment response varies between individuals, and complete clearance cannot be guaranteed.
Omalizumab is generally well tolerated, but allergic reactions, including rare anaphylaxis, are possible. Appropriate medical supervision is important.
Omalizumab helps control disease activity but does not necessarily permanently cure CSU.
Symptoms may recur after treatment is discontinued, and some patients may require a longer treatment period.
3. Dupilumab (Dupixent) – Another Biologic Treatment Option
Dupilumab is a biologic medication that targets inflammatory pathways involving interleukin-4 and interleukin-13.
It is already used in several inflammatory conditions, including atopic dermatitis.
Clinical studies have demonstrated that dupilumab can also improve symptoms in selected patients with inadequately controlled CSU.
It may be considered in appropriate patients depending on previous treatment response, other associated medical conditions and local regulatory approval.
Dupilumab is given by subcutaneous injection.
As with other systemic treatments, the choice of medication should be individualised.
4. Remibrutinib – An Oral Targeted Treatment
Remibrutinib is a newer oral medication that inhibits Bruton's tyrosine kinase (BTK), a signalling enzyme involved in mast cell activation.
By interrupting this pathway, remibrutinib can reduce the release of inflammatory mediators responsible for hives and itching.
Unlike biologic injections, remibrutinib is taken orally.
Clinical trials have demonstrated meaningful improvements in itching and urticaria activity in selected patients with CSU.
Its use depends on local regulatory approval, availability, patient suitability and specialist assessment.
5. Ciclosporin – For Selected Difficult-to-Control Cases
Ciclosporin is an immunosuppressive medication that may be considered in selected patients with severe CSU who remain inadequately controlled despite other treatments.
It can be effective but requires careful monitoring because of potential adverse effects, including increased blood pressure, kidney impairment and medication interactions.
It is generally reserved for patients requiring specialist-directed treatment.
6. What About Oral Steroids?
Oral corticosteroids may temporarily reduce severe urticaria symptoms.
However, long-term oral steroid treatment is not recommended for CSU because of potential complications such as weight gain, raised blood sugar, hypertension, osteoporosis and increased susceptibility to infections.
A very short course may occasionally be considered for a severe flare, but steroids should not become the main long-term treatment strategy.
How Long Does CSU Last?
The duration of CSU varies considerably between individuals.
Some patients improve and enter remission within months, while others may experience recurrent symptoms for several years.
CSU often follows an unpredictable course, with periods of improvement and occasional flare-ups.
It is important to understand that persistent urticaria does not necessarily indicate a dangerous underlying disease.
With appropriate treatment, many patients can maintain normal daily activities despite having chronic urticaria.
Can CSU Be Cured Permanently?
There is currently no treatment that can guarantee a permanent cure for every patient.
However, CSU can enter spontaneous remission, meaning the hives eventually stop occurring without the need for continued medication.
The role of treatment is to keep symptoms controlled while the disease remains active.
Some patients can gradually reduce or discontinue medication after achieving sustained symptom control.
Others may require longer-term maintenance treatment.
The decision to reduce treatment should be made together with the treating dermatologist.
Why Do My Hives Return When I Stop Taking Antihistamines?
This is another common concern.
Antihistamines control the effects of histamine, but they do not necessarily eliminate the underlying tendency for mast cell activation.
Therefore, symptoms may return when medication is stopped while the disease remains active.
This does not mean that your body has become addicted to antihistamines.
It usually indicates that the underlying urticaria has not yet entered remission.
Patients with frequent recurrence may benefit from regular treatment followed by a gradual, supervised step-down approach once stable control has been achieved.
What Can I Do to Reduce CSU Flare-Ups?
Although CSU cannot always be prevented, some practical measures may help minimise aggravating factors.
1. Take medication consistently
Follow the prescribed antihistamine schedule rather than repeatedly stopping and restarting treatment without medical advice.
2. Avoid known aggravating medications
If you notice worsening symptoms after certain painkillers or other medications, discuss this with your doctor.
3. Minimise excessive heat exposure
Choose comfortable clothing and avoid very hot showers if heat aggravates your hives.
4. Maintain regular sleep and stress management
Stress reduction and adequate sleep may improve overall well-being and help minimise symptom aggravation.
5. Avoid unnecessary food restrictions
Do not eliminate multiple food groups unless there is a clear, reproducible relationship or medical advice to do so.
6. Keep a symptom diary
Recording the frequency of hives, associated swelling, medication use and possible aggravating factors can help assess disease control.
When Should You See a Dermatologist?
Consider specialist assessment if:
Hives persist or recur for more than six weeks
Symptoms interfere with sleep, work or daily activities
Regular antihistamines provide inadequate relief
You experience recurrent swelling of the lips or eyelids
You need frequent courses of oral steroids
The diagnosis remains uncertain
Seek emergency medical attention if hives or swelling are accompanied by difficulty breathing, throat or tongue swelling, dizziness, fainting or signs of a severe allergic reaction.
If individual skin lesions remain in the same location for more than 24 hours, are painful rather than itchy, or leave bruising, further assessment may be necessary to exclude other conditions such as urticarial vasculitis.
Final Thoughts
Chronic spontaneous urticaria can be distressing, particularly when itchy rashes continue to appear without an obvious explanation.
However, CSU is not usually caused by a conventional food allergy, and extensive dietary restrictions or repeated allergy testing may not provide the answer.
The most important approach is to confirm the diagnosis, identify relevant aggravating factors and establish a structured treatment plan.
Modern antihistamines remain the first-line treatment, while targeted therapies such as omalizumab and newer treatment options offer additional possibilities for patients with difficult-to-control disease.
Although CSU may persist for months or years, good symptom control is achievable for many patients, and spontaneous remission can occur over time.
About the Author
Dr Lim Tzyy Huei is a Consultant Dermatologist at Pantai Hospital Batu Pahat, Johor, Malaysia.
His clinical practice includes the assessment and management of chronic urticaria, eczema, psoriasis, acne, allergic and inflammatory skin conditions.
Patients with persistent or recurrent hives may benefit from dermatological assessment to confirm the diagnosis and discuss appropriate treatment options.
Disclaimer: This article provides general educational information and does not replace individual medical consultation. Treatment suitability, medication availability and regulatory approval may vary.
