Diagnosis

General

The diagnostic workup of urticaria patients includes a detailed history, physical examination, and basic laboratory testing (1).

Since acute urticaria is self-limiting, diganostic workup is usually limited to anamnesis for possible trigger factors. In the case your acute urticaria might be due to a type I food allergy or drug hypersensitivity, especially for non-steroidal anti-inflammatory drugs (NSAIDs), allergy tests and patient education may be useful to allow patients to avoid re-exposure to relevant causative factors.

For chronic urticaria the diagnostic workup aims to confirm diagnosis and exclude differential diagnoses by e.g. focusing on the underlying causes, identification of relevant conditions that modify disease activity and check for comorbidities and to have a look at the consequences of your chronic urticaria, assessment of predictors of the course of disease and response to treatment and monitoring of disease activity, impact, and control.

(1) 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. 2021; 77(3):734-766

Medical History

In all forms of urticaria, a thorough history is an essential first step of the diagnostic workup, and, in the case of chronic urticaria also helps to assess differential diagnoses (1).

Urticaria, commonly known as hives, is usually diagnosed based on the appearance of itchy wheals and/or angioedema from the patients history and confirmed upon examination by a physician. Taking a photo of the affected skin during an attack is helpful to guide the physician as to whether this is urticaria or not. For example, skin changes like bruising, blood-like spots, or brown discoloration are usually not seen in urticaria.

In addition to assessment of cutaneous signs and symptoms, your doctor will take family anamnesis and ask you questions regarding any other concomitant diseases, medication use, or exposures that may trigger urticaria, and other symptoms that indicate systemic involvement (i.g. fever, joint pain, weight loss, or malaise).

Further anamenestic procedure may inlcude assessment of characteristics of lifestyle, life circumstances, and physical features (i.e. food, smoking habits, type of work, activities, symptom appearance in relation to weekends, holidays, and foreign travel, surgical procedures, relationship to the menstrual cycle, current medication, stress).

Clinical Examination and Identifying the Cause

Triggers

In chronic urticaria, the diagnostic workup includes identification of factors that modify disease activity (1). In acute urticaria symptoms are either elicited by specific triggers (inducible urticaria) or appear spontaneously. Symptoms may exacerbate by unspecific triggers that increase disease activity such as drugs (e.g. NSAID family drugs as diclofenac, aspirin, ibuprofen), infections, stress, or food.

In chronic spontaneous urticaria, symptoms may exacerbate by unspecific triggers that increase disease activity such as drugs (e.g. NSAID family drugs as diclofenac, aspirin, ibuprofen), infections, stress, or food.

Each sub-form of chronic inducible urticaria has its own trigger. Depending on the nature of their triggering factors, the individual medical conditions are divided into symptomatic dermographism (friction), cold urticaria (cold), delayed pressure urticaria (pressure), solar urticaria (light), heat urticaria (heat), vibratory angioedema (vibrations), cholinergic urticaria (increase in body core temperature), contact urticaria (skin contact with triggering agents) and aquagenic urticaria (water). Read more in our section on TRIGGERS

Common Causes

Urticaria develops when specific immune cells in the body, called mast cells, become activated via their surface receptor FcεR1 by the acton of autoallergens or autoantibodies. This causes vessels to dilate and become leaky and mediates activation of sensory nerves. As a result, fluid, immune cells and their messenger substances such as histamine accumulate in the skin and cause redness, swelling and itching. Urticaria can arise from various factors including acute infections, drug or insect bite reactions, and in very rare cases, food allergy. Depending on the pattern of presentation and history, your doctor may be able to identify the cause. However, in the vast majority of cases the cause is not clearly identifiable.

Comorbidities

In case of chronic urticaria, patient’s medical history, physical examination, or basic testing may point to a comorbidity. Findings are recommended to prompt further investigations (i.e. screening for specific diseases by questionnaires, provocation tests, further laboratory tests, referral to a specialist) (1). The most common comorbidities in CSU are CIndUs, autoimmune diseases, and allergies.

Consequences of Chronic Urticaria

Urticaria may severely impact the patient’s quality of life as it is disfiguring, unpredictable and intensely itchy, which can interfere with sleep and activity. Urticaria can become unbearable, causing sexual dysfunction, emotional distress, and possibly leading to depression and anxiety and may require referral to a specialist (1).

Learn more about which other diseases circle around urticaria by listening to episode 21 of “All things Urticaria” podcast via Spotify or via Apple Podcast.

Monitoring of Disease Activity, Impact and Control

Urticaria symptoms have a fleeting nature and are often barely recognizable or not recognizable at all when visiting a doctor. Moreover, as urticaria symptoms often change in intensity, continuous documentation of symptoms is essential. Consequently, self-evaluation of disease activity is tremendously important to ensure optimal treatment for chronic urticaria patients (1). The urticaria app CRUSE® (Chronic Urticaria Self Evaluation) Control Urticaria app is developed by renowned dermatologists and allergologists of the UCARE-Team to help chronic urticaria patients to manage their condition. CRUSE® helps you and your doctor to track disease activity, how you are responding to treatment and how it can be improved.

Learn more about CRUSE® as your pioneer daily companion by listening to episode 35 of “All Things Urticaria” podcast via Spotify or via Apple Podcast.

Physical Examination

Physical examination inlcudes assessment of the cutaneous signs and symptoms, i.e. wheals, angioedema and itch. It is always helpful to have photos of your symptoms since they have a fleeting nature and are often barely recognizable or not recognizable at all when visiting a doctor.

Moreover, as urticaria symptoms often change in intensity, continuous documentation of symptoms is essential. This can be easily done with the urticaria app CRUSE® (Chronic Urticaria Self Evaluation).

In urticaria, wheals are sharply circumscribed (defined), itchy, pale red superficial skin swellings. These wheals may present in variable sizes and shapes and have a fleeting nature, with the skin returning to its normal appearance in around 24 hours. They may appear in only certain parts of the body or may show on the entire body. On intensively pigmented skin, the redness may not be prominently visible.

Wheals may sometimes appear along with angioedema. Angioedema is a sudden, pronounced erythematous or skin-colored deep skin swelling. Angioedema may occur on different parts of the body, for example on the face, lips, hands, and feet. Itching is not frequent, but patients may complain of tingling, burning, tightness, and pain. Resolution of angioedema is slower than that of wheals taking up to 72 hours. Some patients experience angioedema without wheals. These urticaria-typical skin changes can be either localized (wheals, angioedema) or affect the entire body (wheals).

Listen to why itch is strongly linked to whealing in episode 2 of “All Things Urticaria” podcast via Spotify or via via Apple Podcast.

Learn more about Angioedema by listening to the “All Things Angioedema“-Podcast series or in episode 53 of “All Things Urticaria” podcast via Spotify or via Apple Podcast.

Laboratory Testing

Usually, testing is not required to diagnose acute urticaria (lasting less than 6 weeks) (1). Most cases of acute urticaria are non-allergic and, although bothersome, are not dangerous.

The exception is a rare and severe allergic condition, so called anaphylaxis, that may appear with cutaneous symptoms of acute urticaria and may be life-threatening if left untreated. Therefore, in acute urticaria, it is crucial first to identify possible allergic triggers such as food or drugs to exclude your acute urtiaria being a cutaneous symptom of anaphylaxis. If your acute urticaria is suspected to be due to a type I food allergy or drug hypersensitivity (especially for non-steroidal anti-inflammatory drugs/NSAIDs such as diclofenac, ibuprofen and aspirin) allergy testing is recommended. Avoidance of any known trigger of your urticaria is the most crucial step to avoid recurrence in the future.

The basic tests recommended for the diagnostic workup of CSU include a differential blood count and CRP and/or erythrocyte sedimentation rate, in all patients, and total IgE and IG-anti-TPO in patients in specialist care and more biomarkers as appropriate (1). Based on the results obtained by these measures, further diagnostic measures based on the patient history and examination, especially in patients with long-standing and/or uncontrolled disease are recommended.

In patients with CIndU, the routine diagnostic workup aims to identify the subtype of CIndU, and to determine trigger thresholds (1). The last of these is important as it allows for assessing disease activity and response to treatment. For most CIndU subtypes, validated tools for provocation testing are available.

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