Chronic Urticaria

Urticaria is a condition characterized by the development of wheals (hives), angioedema, or both, and is a predominantly mast cell-driven disease.^[1] A wheal has 3 typical features: a sharply circumscribed, central swelling of variable size and shape, almost invariably surrounded by reflex erythema; an itching or sometimes burning sensation; and a fleeting nature, with the skin returning to its normal appearance usually within 30 minutes to 24 hours.^[1] Angioedema is characterized by a different set of 3 features: a sudden, pronounced, erythematous or skin-coloured deep swelling of the lower dermis and subcutis, or of mucous membranes; tingling, burning, tightness, and sometimes pain rather than itch; and a resolution that is slower than a wheal's, which can take up to 72 hours.^[1]

Urticaria is classified two ways. By duration: acute urticaria is the occurrence of wheals, angioedema, or both for 6 weeks or less; chronic urticaria (CU) is the occurrence of wheals, angioedema, or both for more than 6 weeks, which can come with daily or almost-daily signs and symptoms, or with an intermittent, recurrent course over months or years.^[1] By the role of a definite trigger: chronic spontaneous urticaria (CSU) — the term that has replaced "chronic idiopathic urticaria" — has no definite eliciting factor, while chronic inducible urticaria (CIndU) is provoked by a definite and specific trigger that reliably and reproducibly produces wheals, angioedema, or both when present and never when absent.^[1][2] A patient can have more than one form of CU at once — CSU together with one or more CIndU subtypes are common — and each form can respond independently to treatment.^[1]

CSU is not rare: Canadian data put its prevalence at roughly 0.5% to 1% of the general population, occurring most commonly in women, with a peak age of onset between 20 and 40 years.^[2] Angioedema accompanies wheals in an estimated 33% to 66% of CSU patients, and 10% to 50% of patients have disease lasting longer than 5 years.^[2] Chronic urticaria is genuinely disabling: it impairs quality of life and work/school performance to a degree comparable with coronary artery disease in some studies, and it carries a substantial cost burden for patients and the health system.^[1] The pharmacist's highest-value contribution here is threefold: confirming the pattern really is ordinary chronic urticaria rather than one of its more serious mimics, driving a genuinely stepped pharmacotherapy ladder rather than defaulting to a sedating first-generation antihistamine, and recognizing the specific red flags — a lesion lasting more than 24 hours, or angioedema with airway involvement — that change the plan entirely.

Chronic spontaneous urticaria: numerous erythematous, variably sized wheals with surrounding reflex erythema — each individual wheal typically fades within 24 hours as new ones appear elsewhere. (Allergyresearch, CC BY 4.0, Wikimedia Commons)

Chronic spontaneous urticaria (CSU)

CSU presents as spontaneous, recurring wheals, angioedema, or both, without a definite identifiable eliciting factor, for more than 6 weeks.^[1] Based on current evidence, CSU itself has recognized causes even though no external trigger is identifiable: Type I autoimmunity (also called "autoallergic" CSU, driven by IgE autoantibodies against self-antigens) and Type IIb autoimmunity (driven by mast cell-activating autoantibodies, typically IgG against the IgE receptor or against IgE itself); when neither mechanism is identified, the cause is labelled unknown.^[1] An autoimmune component of this kind is found in roughly 45% of CSU patients, and about 25% of CSU patients also have thyroid autoantibodies, though in CSU these do not correlate with altered thyroid function.^[2]

Chronic inducible urticaria (CIndU) — 8 recognized subtypes

CIndU is characterized by definite, subtype-specific triggers that always produce wheals, angioedema, or both when present and never when absent.^[1] The recognized subtypes are symptomatic dermographism (formerly urticaria factitia or dermographic urticaria), cold urticaria, delayed pressure urticaria, solar urticaria, heat urticaria, and vibratory angioedema — collectively referred to as chronic physical urticaria — plus cholinergic urticaria, contact urticaria, and aquagenic urticaria.^[1] Rare subtypes exist where 2 or more definite triggers must combine to provoke symptoms, for example cold-induced cholinergic urticaria.^[1]

Selected CIndU subtypes

Symptomatic dermographism

Linear wheals appear within minutes where the skin is scratched, rubbed, or under friction from clothing. It can be confused with spontaneous CSU because seemingly spontaneous hives are actually caused by loose-fitting clothing rubbing on the skin or unintentional scratching.^[1] Diagnosed with a dermographometer or a standardized threshold-testing device (e.g., FricTest).^[1]

Cold urticaria

Wheals and sometimes angioedema develop on rewarming after cold exposure — cold air, water, or objects. Diagnosed with a cold provocation and threshold test, for example using a Peltier element-based device.^[1] Swimming in cold water carries a genuine risk of a large-surface-area reaction with hypotension, so patients need explicit counselling on this.

Delayed pressure urticaria

Deep, often painful swelling develops 30 minutes to several hours after sustained pressure — from tight waistbands, shoulder straps, or standing/sitting on a hard surface. Diagnosed with a pressure test and threshold testing using graded weighted rods.^[1] Patients should be counselled that pressure is force per area, so broadening the contact area of straps and bags can reduce symptoms.

Cholinergic urticaria

Small, punctate wheals with a surrounding flare erupt with or shortly after a rise in core body temperature — exercise, hot showers, spicy food, fever, or emotional stress — and in severe cases can be accompanied by facial swelling resembling angioedema. Diagnosed with exercise or heat provocation and threshold testing, for example pulse-controlled ergometry.^[1]

Cholinergic urticaria: an eruption of small, discrete wheals on the trunk, provoked by a rise in core body temperature from exercise. (Klope62, CC BY 3.0, Wikimedia Commons)

Solar, heat, aquagenic, vibratory, and contact urticaria

Solar urticaria follows exposure to a specific wavelength of UV or visible light; heat urticaria follows direct contact with a hot object or surface; aquagenic urticaria follows skin contact with water of any temperature; vibratory angioedema follows vibration (e.g., power tools, a motorcycle, or a towel briskly dried against the skin); and contact urticaria follows direct skin contact with a specific substance. Each is diagnosed with its own subtype-specific provocation and threshold test.^[1]

Angioedema

Angioedema is a sudden, deep swelling of the lower dermis, subcutis, or mucous membranes, typically involving the lips, eyelids, tongue, hands, feet, or genitalia, and sometimes the gastrointestinal mucosa, producing abdominal pain rather than a visible swelling. Unlike a wheal, it is usually not itchy — patients describe tingling, burning, tightness, or pain — and it resolves more slowly, sometimes taking up to 72 hours.^[1][2] It is typically asymmetric and non-dependent.^[2] Angioedema can occur together with wheals in CSU or any CIndU subtype, or it can occur in isolation, which should prompt consideration of a bradykinin-mediated cause rather than ordinary urticaria — see Red Flags & Refer.

Angioedema of the face, most strikingly involving the upper lip — a deep, non-itchy, asymmetric swelling that resolves more slowly than an ordinary wheal. (Boussetta N, Ghedira H, Hamdi MS, et al., CC BY 4.0, Wikimedia Commons)

• Female sex and a peak age of onset between 20 and 40 years, though CSU occurs at any age.^[2]
• An autoimmune component — Type I ("autoallergic") or Type IIb autoimmunity — identified in roughly 45% of CSU patients.^[2]
• Thyroid autoantibodies, present in about 25% of CSU patients, and a personal history of another autoimmune disease.^[2]
• Concomitant chronic inducible urticaria, high disease activity, an elevated CRP, and/or the presence of angioedema — each is linked to a longer expected duration of CSU and a poorer response to antihistamine treatment.^[1]
• NSAID and aspirin intake as an aggravating (not causative) factor — up to 1 in 4 CSU patients has their disease activity worsened by NSAIDs, with paracetamol (acetaminophen) and/or a COX-2 inhibitor generally safer alternatives.^[1]
• Stress — up to one-third of CSU patients report their disease activity is linked to stress.^[1]
• Possible aggravating (not clearly causative) chronic infectious or inflammatory processes, including Helicobacter pylori-associated gastritis, other gastritis, reflux esophagitis, or nasopharyngeal bacterial infection — evidence for a causal role is inconsistent and intensive screening for infectious causes in every patient is not advised.^[1]
• A family history of chronic urticaria.
• For each CIndU subtype: exposure to its specific trigger — cold air, water, or objects; sustained pressure or tight clothing; a rise in core body temperature from exercise, heat, or emotional stress; a specific light wavelength; skin contact with water; vibration; or direct skin contact with a specific substance.^[1]

History

Take a detailed history first — it is the essential first step in the diagnostic workup of every urticaria patient.^[1] Ask specifically: "For how long does each individual wheal last?" (fleeting and under 24 hours points to ordinary urticaria; persisting longer points toward vasculitis) and, when a trigger is suspected, "Can you make your wheals appear? Can you bring out your wheals?"^[1] Review any photographs the patient has taken, since wheals and angioedema are transient and often not present at the time of the visit.^[1] Ask about pain versus itch, angioedema episodes and their distribution, systemic symptoms (fever, joint pain, malaise), a family history of angioedema or early age of onset, and current medications — specifically NSAIDs and any ACE inhibitor, angiotensin receptor blocker, gliptin, or neprilysin inhibitor.^[1]

Physical examination

Examine any active wheals or angioedema for the typical features described in Recognize the Condition, and specifically look for bruising, purpura, or residual hyperpigmentation at sites of prior wheals, which is not expected in ordinary urticaria.

Recommended diagnostic tests by urticaria type

Further, individually selected testing — for example allergy testing, thyroid autoantibodies, an avoidance diet, or a lesional skin biopsy — is reserved for when the basic workup, history, or examination points to a specific underlying cause or an alternative diagnosis; broad, unfocused screening panels are not recommended.^[1]

Differential diagnosis

A skin biopsy is not needed for typical, fleeting, itchy wheals, but should be obtained when any of the following are present: a wheal duration of 24 hours or more, bruising or post-inflammatory hyperpigmentation, or accompanying systemic symptoms — any one of these should guide the decision to biopsy.^[3]

Scoring disease activity and control

Use validated tools at every visit rather than an unstructured impression.^[1] For wheal-predominant disease, the Urticaria Activity Score (UAS7) sums a daily 0-3 wheal score and a daily 0-3 pruritus score over 7 consecutive days (maximum 42), and the Urticaria Control Test (UCT) is a 4-item, 4-week-recall tool with a cutoff of 12 out of 16 points for "well-controlled" disease.^[1] For angioedema, the parallel tools are the Angioedema Activity Score (AAS), summed over 4 weeks, and the Angioedema Control Test (AECT), a 4-item tool with a cutoff of 10 out of 16 points for well-controlled disease.^[1] Patients with both wheals and angioedema should be assessed with both pairs of tools.^[1]

• Achieve complete symptom control — a continuous UAS7 of 0 — as safely as possible, individualized to each patient.^[1]
• Search for and, where genuinely feasible, eliminate or reduce identifiable aggravating factors (NSAIDs, stress) without delaying real pharmacotherapy while doing so.^[1]
• Follow the assess-adjust-act cycle at every visit: assess disease activity/control/impact with UAS7, UCT, AAS, and/or AECT; adjust by stepping up if control is inadequate, changing therapy if side effects occur, or stepping down if the patient has been symptom-free for 3-6 months; act by treating comorbidities, applying non-pharmacologic measures (especially in CIndU), and educating the patient.^[1]
• Use non-sedating second-generation H1-antihistamines continuously, not on an as-needed basis, as the backbone of therapy for every urticaria type.^[1]
• Minimize exposure to first-generation antihistamines and to long-term systemic corticosteroids — neither belongs in routine chronic urticaria management.^[1][4]
• Track angioedema burden separately from wheal burden using the AAS and AECT, since the two do not always track together.^[1]
• Restore quality of life, and screen for and address the anxiety, depression, sleep disturbance, and sexual dysfunction that commonly accompany chronic urticaria.^[2]

• Advise patients to discontinue any medication suspected of worsening chronic spontaneous urticaria, most commonly NSAIDs — paracetamol (acetaminophen) and/or a COX-2 inhibitor are generally safer analgesic alternatives in CSU.^[1]
• For CIndU, provide clear, practical information to help patients recognize and minimize exposure to their specific trigger — for example, broadening the contact area of straps and waistbands in delayed pressure urticaria, or choosing sunscreens and light-filtering options matched to the specific provoking wavelength in solar urticaria.^[1] Counsel explicitly that avoidance alone often does not fully control CIndU and can come with a real quality-of-life cost — patients with cholinergic urticaria who abstain from physical exercise, or with solar urticaria who avoid being outdoors, can become markedly more impaired by the avoidance than by the disease itself.^[1]
• Tolerance induction (rush hardening) can help in some CIndU subtypes, notably cold, cholinergic, and solar urticaria — for example, a rush ultraviolet-A regimen has been reported effective within 3 days for some patients.^[1] However, the induced tolerance typically lasts only a few days, so consistent daily exposure to the trigger at threshold level is required to maintain it, and many patients do not accept or tolerate this long-term.^[1]
• A pseudoallergen-free or low-histamine diet is controversial and unproven in well-designed double-blind placebo-controlled studies; if trialled, maintain it for only 2-3 weeks before assessing benefit, and do not let a diet trial delay effective pharmacotherapy.^[1]
• Screen for and address the psychosocial burden of chronic urticaria directly — anxiety, depression, sleep disturbance, and sexual dysfunction are all common consequences, and stress itself can be a genuine aggravating factor for CSU activity.^[2][1]
• Do not order intensive, costly general screening programs "to find the cause" in every chronic urticaria patient — this is specifically advised against; testing should be guided by history, examination, and basic labs rather than performed reflexively.^[1]
• Educate every patient on the difference between isolated urticaria/angioedema and true anaphylaxis, and on when epinephrine and emergency care — not just an antihistamine — are needed.

Pregnancy

Breastfeeding

Second-generation H1-antihistamines are excreted into breast milk in low concentrations and their use is generally advised, with loratadine again preferred given the largest safety experience; note that loratadine is metabolized in the liver, which is not the case for its metabolite desloratadine.^[1] Avoid first-generation antihistamines in lactation — nursing infants can develop sedation from first-generation agents transmitted through breast milk.^[1] Omalizumab has been reported safe in lactation to date.^[1]

Children

Second-generation H1-antihistamines with demonstrated efficacy and safety in the pediatric population include bilastine, cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, and rupatadine — the choice depends partly on the licensed lowest age and available formulation (syrup versus fast-dissolving tablet) in a given country, since modern second-generation agents are often not licensed below 6 months of age.^[1] Do not reach for a first-generation antihistamine as first-line in children despite it being common practice in some settings — it has an inferior safety profile compared with second-generation agents and is not recommended.^[1] The same stepped algorithm is suggested in children, used with caution and weight-adjusted dosing; updosing and the later steps of the ladder are not well studied in this age group and further treatment decisions should be individualized.^[1] A short corticosteroid course, when genuinely needed, should be used only as a very restricted measure in children.^[1]

Older adults

Age itself does not change the recommended ladder, but it sharply raises the stakes of choosing a first-generation antihistamine — anticholinergic burden, sedation, falls, and cognitive impairment are all disproportionately harmful in this group, reinforcing that second-generation agents are the appropriate choice from the outset. Dose-adjust renally cleared agents (cetirizine, levocetirizine, fexofenadine) for reduced renal function, and monitor more closely for cyclosporine-related nephrotoxicity and hypertension given age-related decline in renal reserve.

Autoimmune-associated CSU

Consider thyroid function and autoantibody testing in specialist care given the roughly 25% prevalence of thyroid autoimmunity in CSU.^[2] Direct reduction of functional autoantibodies by plasmapheresis has shown temporary benefit in some severely affected, treatment-unresponsive, autoantibody-positive patients, but experience and evidence are limited and cost is high — this remains a specialist-only, last-resort option.^[1]

Renal impairment

Dose-adjust cetirizine, levocetirizine, and fexofenadine for reduced renal function. Cyclosporine is nephrotoxic — use with particular caution and close monitoring in any degree of renal impairment.

Hepatic impairment

Desloratadine and loratadine are hepatically metabolized; use with caution in significant hepatic impairment. Cyclosporine is metabolized via CYP3A4 — monitor liver function and screen carefully for interacting drugs.

1. Inadequate control on a standard-dose 2nd-generation antihistamine after 2-4 weeks (sooner if symptoms are intolerable): updose the same agent up to 4x standard dose, rather than switching to or adding a different 2nd-generation antihistamine, or reaching for a 1st-generation agent.^[1]
2. Inadequate control on an updosed antihistamine within up to 6 months (sooner if intolerable): add omalizumab 300 mg SC every 4 weeks, rather than pushing the antihistamine dose above 4x (untested and not recommended).^[1]
3. Inadequate response to licensed-dose omalizumab: consider a specialist-directed dose increase (up to 600 mg) and/or interval shortening (down to every 2 weeks) before concluding the drug has failed.^[1]
4. Inadequate response to optimized omalizumab: add cyclosporine 3-5 mg/kg/day under specialist supervision, continuing the background antihistamine; do not reach for cyclosporine before omalizumab has had an adequate trial, given its less favourable safety profile.^[1]
5. Apparent "treatment failure" that does not fit the expected pattern: reassess for urticarial vasculitis (wheals over 24 hours, painful, bruising), mastocytosis, an autoinflammatory disease, or bradykinin-mediated angioedema before escalating urticaria-specific therapy any further.^[3]
6. A severe acute flare needing rapid relief while stepping up maintenance therapy: a brief corticosteroid course can bridge the gap, but is not itself a "next step" therapy and should never become routine or long-term.^[1]
7. Refractory disease despite the full ladder including cyclosporine: refer to a specialist urticaria centre; further options (montelukast, dapsone, sulfasalazine, methotrexate, and other immunosuppressants) carry only low-quality evidence and are used case by case in specialist care.^[1]

• Reaching for a first-generation antihistamine as first-line "because it works faster or stronger" — second-generation agents are the recommended first-line for every type of urticaria, and first-generation agents add anticholinergic, sedative, and cognitive risk without a demonstrated efficacy advantage.^[4]
• Combining 2 different second-generation antihistamines together instead of updosing a single agent — this is specifically recommended against.^[1]
• Jumping straight to omalizumab or cyclosporine without first trialling updosing the second-generation antihistamine to 4x standard dose.^[1]
• Using cyclosporine before an adequate trial of omalizumab, given cyclosporine's inferior safety profile.^[1]
• Treating a patient whose individual wheals last more than 24 hours and leave bruising as simply "refractory" chronic urticaria rather than obtaining a lesional skin biopsy for urticarial vasculitis.^[3]
• Missing recurrent angioedema without wheals as bradykinin-mediated (ACE inhibitor or hereditary) and treating it with antihistamines or omalizumab, neither of which works for bradykinin-mediated swelling.^[1]
• Continuing systemic corticosteroids long-term for "maintenance" control — a strong recommendation against; reserve for brief rescue courses only.^[1]
• Ordering an extensive, costly diagnostic screening panel in every new chronic urticaria patient rather than the limited, guideline-directed basic tests.^[1]
• Delaying real pharmacotherapy for a prolonged empiric pseudoallergen-free or low-histamine diet trial.^[1]
• Leaving a patient on escalated therapy (updosed antihistamine, omalizumab, or cyclosporine) indefinitely rather than reassessing for step-down every 3-6 months once they are symptom-free.^[1]
• Missing that ongoing NSAID use — aspirin included — may be an aggravating factor for up to 1 in 4 CSU patients, with paracetamol or a COX-2 inhibitor as safer analgesic alternatives.^[1]

Second-Generation H1-Antihistamines (Non-Sedating) — First-Line for All Urticaria Types

Taken continuously, not as-needed. If a standard dose is inadequate after 2-4 weeks, updose the SAME agent up to 4x rather than switching or combining agents.

First-Generation H1-Antihistamines — Not Recommended for Routine Use

Listed to state explicitly why these should not be first-line, or routine, choices for chronic urticaria at any age — not as an alternative option.

Anti-IgE Biologic — Third-Line Add-On

Initiate and monitor under specialist supervision. Continue the background 2nd-generation antihistamine alongside it.

Immunosuppressant — Fourth-Line Add-On

Reserve for disease refractory to antihistamine plus omalizumab in combination. Off-label for urticaria. Initiate and monitor under specialist supervision.

Short-Course Corticosteroid — Acute Severe Exacerbation Only

Never for long-term or maintenance use in chronic urticaria — this is a strong recommendation, not a judgment call.

Adjunctive / Low-Evidence Option

Not part of the core 4-step ladder. Listed because it is sometimes used as an adjunct, with the evidence quality made explicit.

Emergency Treatment — Airway-Threatening Angioedema or Anaphylaxis

Use without hesitation whenever anaphylaxis criteria are met alongside urticaria or angioedema — an antihistamine alone is not adequate for an airway emergency. See the Anaphylaxis chapter for full management.