Urticaria (hives) — what causes it, what helps, and when chronic itching is more than just an allergy

In brief

• Hives (urticaria) are itchy, raised wheals that each fade within 24 hours; hives lasting over 6 weeks are rarely due to allergy.
• A second-generation antihistamine taken every day is the mainstay, at up to four times the licensed dose if needed.
• Most chronic urticaria settles with time, about half within 1–2 years; persistent cases may need specialist treatment, such as omalizumab injections.
• Swelling of the face or lips on an ACE inhibitor blood pressure tablet means stopping it for good.
• Call 995 immediately for throat or tongue swelling, voice change, difficulty swallowing or breathing, or feeling faint.

We assess and treat hives at our Punggol clinic. Book a skin appointment.

What urticaria actually is

A hive, or wheal, is a raised, itchy, often pink or pale-red swelling that typically lasts less than 24 hours in any one spot, moving and changing from day to day. Mast cells, immune cells in the skin, release histamine and other inflammatory chemicals. These make small blood vessels leak, causing swelling, redness and itch. Each wheal leaves no mark, though new ones keep appearing elsewhere.

Why “allergy” is often the wrong frame:

• A true allergic (IgE-mediated) reaction needs repeated exposure to a specific trigger.
• Mast cells release histamine for many non-allergic reasons: viral infections, medicines acting on mast cells directly (such as some painkillers, opioids and contrast dyes), pressure or scratching, heat, cold, exercise, and autoimmune triggers, where the body’s own antibodies activate mast cells with no external trigger.
• In chronic urticaria (lasting more than 6 weeks), the cause is usually autoimmune or idiopathic, not an allergy.

So the question shifts from “what is causing this?”, often unanswerable, to “how do we control it?”, which is almost always achievable.

Acute vs chronic — the 6-week rule

An arbitrary but useful definition:

• Acute urticaria lasts less than 6 weeks. It is common, affecting about 1 in 5 people at some point in their lives, and usually settles by itself.
• Chronic urticaria means wheals on most days for more than 6 weeks, and affects about 1–2% of people at some point in their lives. Most is chronic spontaneous urticaria (no identifiable trigger). A smaller share is chronic inducible urticaria, reproducibly triggered by a physical stimulus. It needs a structured, longer-term approach.

Acute urticaria — usually a transient problem

Most acute episodes:

• Follow a viral infection: a few days of hives during or after a cold, sore throat or flu-like illness is very common.
• Sometimes follow a medicine: antibiotics (particularly penicillins), NSAIDs (like aspirin or ibuprofen) or opioids.
• Occasionally follow a food, but only if hives appear consistently within 1–2 hours of the same food on several occasions, with no other trigger. Random food links during a 2-week episode are usually coincidence.
• Resolve by themselves over days to weeks.

Treatment is a daily second-generation antihistamine for the whole episode; regular blocking works better than “as needed”. A short course of oral prednisolone can shorten a severe episode with very widespread wheals or swelling (see below).

If it settles within 6 weeks and doesn’t return, no further tests are needed. If it persists or recurs, we follow the chronic urticaria pathway.

Chronic urticaria — the bigger picture

At any given time, chronic urticaria affects about 0.5–1% of people, with somewhat higher figures in studies from Asia. It fluctuates and can be daily or intermittent. Most cases settle with time: about half within 1–2 years and most by 5 years, though some people have it longer.

Chronic spontaneous urticaria (CSU)

By far the most common form, with no identifiable trigger. About 30–50% of cases are autoimmune: antibodies against the IgE receptor on mast cells trigger histamine release. Many cases are simply idiopathic (cause unknown). We don’t always find a cause, and we usually don’t need to, because the treatment ladder works either way.

Chronic inducible urticaria (CIndU)

Wheals appear reproducibly with a physical trigger:

• Dermographism: wheals along scratched lines on the skin (the most common)
• Cold urticaria: cold air, cold water or holding a cold object
• Heat urticaria: warmth (rare)
• Pressure urticaria: wheals hours after sustained pressure, such as a tight waistband or prolonged sitting
• Solar urticaria: sun exposure
• Cholinergic urticaria: small, uniform (monomorphic) wheals triggered by sweating from exercise, hot showers or emotional stress
• Aquagenic urticaria: water itself, whatever its temperature (rare)

The trigger is usually clear from the history. Specialist physical urticaria testing (such as cold provocation or a dermographometer) sometimes helps confirm it and assess severity. We don’t do these tests, but can refer you to a dermatologist for them.

Workup for chronic urticaria — what we test, what we don’t

For most patients with chronic urticaria, we check only:

• Full blood count (FBC): eosinophilia, infection or other blood clues
• ESR or CRP: markers of inflammation
• Thyroid function (TSH): autoimmune thyroid disease is associated with chronic spontaneous urticaria
• Liver function tests (LFT): a baseline before starting medicines
• Total IgE: sometimes useful, particularly if biologic therapy is being considered

We don’t routinely order:

• Specific IgE / RAST food panels: high false-positive rate. Food allergy rarely causes chronic urticaria, and testing leads to unnecessary food avoidance.
• Allergy skin-prick testing, which we reserve for a history clearly suggesting a specific allergic trigger.
• Extensive autoimmune panels, unless other clues suggest a systemic autoimmune condition.
• Helicobacter pylori testing: the historical link is weak, so we test only if symptoms suggest gastritis.

If your history clearly points to a trigger, we may target testing or try an elimination.

Angioedema — when the swelling is deeper

Angioedema is deep swelling of the skin or mucous membranes, typically of the lips, eyes, hands, feet or genitals. It can occur with hives or on its own. It lasts longer than wheals (usually 24–72 hours) and tends to be uncomfortable rather than itchy.

Histamine-related angioedema (the common type)

Often part of an urticaria episode. It responds to antihistamines and settles by itself.

ACE inhibitor-related angioedema

ACE inhibitors (lisinopril, enalapril, perindopril, ramipril), common blood pressure medicines, can cause angioedema, sometimes years into treatment. It often involves the face, lips, tongue or throat, and does not respond to antihistamines or steroids. The treatment is to stop the ACE inhibitor permanently and switch, usually to an ARB, though there is a small risk of cross-reaction. If this happens, please do not restart it on your own.

Hereditary angioedema (rare but important)

A rare genetic condition causing recurrent angioedema (often of the face, abdomen or larynx) without urticaria, often with a family history. It doesn’t respond to antihistamines or steroids, and needs specialist treatment with C1-esterase inhibitor or related agents. If we suspect it, particularly with gut or throat attacks, we refer to allergy/immunology.

Urgent — angioedema involving the throat is an emergency

Throat or tongue swelling, voice change, difficulty swallowing, or any breathing difficulty: call 995 immediately or go to the nearest emergency department. Don’t wait.

The treatment ladder — step by step

Urticaria treatment follows an internationally agreed step-up approach (the international EAACI/GA²LEN/EuroGuiDerm/APAAACI urticaria guideline, 2022, updated in 2026). The goal is complete control (no wheals, no itch) with the minimum effective treatment.

Step 1 — Second-generation H1 antihistamine at the licensed dose

The mainstay. We usually choose from:

• Cetirizine 10 mg once daily
• Loratadine 10 mg once daily
• Fexofenadine 180 mg once daily
• Bilastine 20 mg once daily (newer, well tolerated, no major drug interactions; less commonly stocked locally)
• Desloratadine 5 mg once daily

The same drugs treat allergic rhinitis, but the dosing strategy differs.

• Take it every day, not “as needed”. Hives respond to continuous blockade, not rescue doses.
• Second-generation, not first-generation. Older sedating antihistamines (chlorpheniramine, hydroxyzine, diphenhydramine) cause drowsiness and other side effects, and the newer ones are at least as effective.
• Try it for 2–4 weeks. If control is incomplete, move up.

Step 2 — Increase the dose, up to four times the licensed dose

If the standard dose isn’t enough, the same antihistamine at up to four times the licensed dose is recommended internationally (EAACI Guideline 2022). It is off-label for most products, but well evidenced and standard practice. For example, cetirizine taken as two 10 mg tablets morning and evening gives 40 mg total daily, divided.

This works for many people who didn’t respond at the standard dose. Drowsiness or dry mouth sometimes appear at higher doses, but are usually mild. We discuss the off-label use with you and document your agreement.

Step 3 — Refer for add-on omalizumab or a newer treatment

If high-dose antihistamine still doesn’t fully control symptoms, the next step is to add omalizumab while continuing the antihistamine. We refer to dermatology for this:

• Omalizumab (Xolair): an anti-IgE monoclonal antibody injected under the skin every 4 weeks. It is highly effective for chronic spontaneous urticaria, and many people achieve complete control. It is specialist-led, needs ongoing administration and monitoring, and is costly, though some insurance plans may cover it.
• Newer options: dupilumab injections are approved in Singapore for chronic spontaneous urticaria from age 12, and remibrutinib tablets have been approved in some other countries. A dermatologist can advise on what is available and suitable for you.

Step 4 — Ciclosporin, under a specialist

If urticaria remains severe despite these treatments, a specialist may add ciclosporin, an immunosuppressant tablet. It is off-label for urticaria and has more side effects, so it is reserved for severe cases.

What about H2 blockers and montelukast?

Older guidelines suggested adding an H2 blocker (such as famotidine) or montelukast. The current international guideline no longer includes them in its treatment steps, because the evidence for them is limited. A specialist may still try one in selected cases. Montelukast also carries an FDA black-box warning (2020) about neuropsychiatric side effects: sleep disturbance, mood changes and, rarely, suicidal thoughts, so we don’t routinely use it.

If urticaria still disrupts your life despite high-dose antihistamines, tell us and we will refer you.

Severe acute flares — short prednisolone bursts

For severe acute urticaria, with widespread wheals, marked discomfort or major disruption to daily life, a short oral prednisolone burst can dramatically shorten the episode. The usual dose is 30–40 mg daily for 3–5 days, with no taper needed at this short duration.

We prescribe it when clinically warranted, but judiciously. It is not for chronic urticaria, because long-term oral steroids carry their own risks and don’t address the underlying problem. Nor is it for mild episodes that antihistamines will settle.

Adrenaline auto-injectors — when they’re appropriate

Adrenaline auto-injectors (EpiPen, Anapen) are for anaphylaxis: a different, life-threatening allergic reaction involving several body systems (skin, breathing, blood pressure, gut). They are not generally needed for urticaria, even when severe. Adrenaline is appropriate if you have:

• A history of anaphylaxis (not just hives) to a known trigger
• Hives plus throat tightness, breathing difficulty, dizziness or vomiting after exposure to a specific trigger

If you carry an adrenaline pen, we will check that you know how and when to use it, and that it is in date. Unsure whether you need one? Ask us.

Things that may not help

• Indiscriminate elimination diets: cutting out several food groups almost never helps chronic urticaria. Short-term placebo responses are common, long-term benefit is rare, and the nutritional risk is real.
• “Detox” or anti-inflammatory protocols: no evidence in urticaria.
• Probiotics: limited evidence.
• Antifungals or antibiotics for unproven H. pylori or “candida”: not supported.
• Stopping all medicines “in case they’re the cause”: trial removal of a specific suspect (an NSAID or ACE inhibitor) can be sensible; blanket stopping of essential medicines is not.
• Antihistamines only as needed, or first-generation sedating ones as the main treatment (see Step 1).

If something has clearly helped you, tell us. We would rather know.

When to come and see us

Book a visit if:

• Hives have been daily or near-daily for more than 2–4 weeks. We can start a structured plan.
• A standard antihistamine isn’t working. We can step up treatment.
• You’ve had angioedema, particularly of the face, and are unsure why.
• You’re on an ACE inhibitor and have had angioedema. We need to switch your blood pressure medicine.
• Urticaria is significantly affecting your sleep, work, school or mood. It is treatable.
• You’ve been doing your own elimination diet. We can reassess and target any tests.
• You’ve had urticaria with breathing difficulty, throat tightness or dizziness, even once. Come in, or attend A&E.

Urgent — call 995 or attend the nearest emergency department

• Throat swelling, voice change, difficulty swallowing, breathing difficulty, wheezing or feeling faint with urticaria may be anaphylaxis. Use your adrenaline auto-injector if you have one, and call 995 immediately. Do not drive yourself.

Get in touch

Punggol — 658 Punggol East, #01-04, Singapore 820658 · Tel 6312 4589

Joo Chiat — 172 Joo Chiat Road, #01-01, Singapore 427443 · Tel 6920 1952

Email — admin@ktmc.sg

References

Guidelines and consensus statements

• Zuberbier T, Abdul Latiff AH, Abuzakouk M, et al. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Allergy. 2022;77(3):734–766.
• Zuberbier T, Ansari ZA, Abdul Latiff AH, et al. The international guideline for the definition, classification, diagnosis and management of urticaria. Allergy. 2026;81(8):2582–2632.
• Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. American Academy of Allergy, Asthma & Immunology / Joint Task Force on Practice Parameters. J Allergy Clin Immunol. 2014;133(5):1270–1277.
• Powell RJ, Leech SC, Till S, et al. BSACI guideline for the management of chronic urticaria and angioedema. Clin Exp Allergy. 2015;45(3):547–565.

Epidemiology

• Zuberbier T, Balke M, Worm M, Edenharter G, Maurer M. Epidemiology of urticaria: a representative cross-sectional population survey. Clin Exp Dermatol. 2010;35(8):869–873.
• Fricke J, Ávila G, Keller T, et al. Prevalence of chronic urticaria in children and adults across the globe: systematic review with meta-analysis. Allergy. 2020;75(2):423–432.

Omalizumab and biologic therapy

• Maurer M, Rosén K, Hsieh HJ, et al. Omalizumab for the treatment of chronic idiopathic or spontaneous urticaria. N Engl J Med. 2013;368(10):924–935.
• Kaplan A, Ferrer M, Bernstein JA, et al. Timing and duration of omalizumab response in patients with chronic idiopathic/spontaneous urticaria. J Allergy Clin Immunol. 2016;137(2):474–481.
• Maurer M, Casale TB, Saini SS, et al. Dupilumab in patients with chronic spontaneous urticaria (LIBERTY-CSU CUPID): two randomized, double-blind, placebo-controlled, phase 3 trials. J Allergy Clin Immunol. 2024;154(1):184–194.
• Metz M, Giménez-Arnau A, Hide M, et al. Remibrutinib in chronic spontaneous urticaria. N Engl J Med. 2025;392(10):984–994.
• Health Sciences Authority (HSA), Singapore. New drug indication approval: Dupixent (dupilumab) for chronic spontaneous urticaria in patients aged 12 years and older, approved 20 November 2025. hsa.gov.sg

Montelukast safety

• U.S. Food and Drug Administration. FDA requires Boxed Warning about serious mental health side effects for asthma and allergy drug montelukast (Singulair). FDA Drug Safety Communication, March 2020.

Hereditary angioedema

• Maurer M, Magerl M, Betschel S, et al. The international WAO/EAACI guideline for the management of hereditary angioedema — the 2021 revision and update. Allergy. 2022;77(7):1961–1990.

This information is for general education only and is not a substitute for medical advice. Urticaria management is individualised — please attend a consultation for assessment. v1.1 · October 2026 (v1.0 April 2026) · Review due April 2028.