Urticaria
The term “urticaria” is derived from the Latin name “Urtica” for species of stinging nettle common in Europe, which causes similar skin reactions. Urticaria is a common skin disease, afflicting approximately one in five individuals at some point during their life. It manifests as sudden wheals on the skin, often accompanied by deep swelling known as angioedema. Some patients experience angioedema without wheals. These urticaria-typical skin changes can be either localized (wheals, angioedema) or affect the entire body (wheals).
For additional information about urticaria, visit our YouTube channel.
Wheals
In urticaria, wheals are sharply circumscribed (defined), itchy, pale red superficial skin swellings (hives). 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.
Listen to why itch is strongly linked to whealing in episode 2 of “All Things Urticaria” podcast via Spotify or via Apple Podcast.
History of Urticaria
Hippocrates (460-377 BC) described elevated itchy lesions caused by nettles and mosquitoes, which he called “knidosis”, after the Greek word for nettle (knido). In the 10th century, Ali Ibu Al-Abbas called it “essera”, which in the Persian language means elevation. The word “urticaria” was first introduced in 1769 by William Cullen in his book “Synopsia Nosalogiae Methodica”. Jean Astruc (1684-1766), the founder of modern dermatology and histology, showed that the weal (or wheal) was due to local obstruction of oedema. Dale and Laidlow showed that the tissue contained an amine that affected smooth muscles and vessels and called it histamine. In the last few decades, great advances in the diagnosis and treatment of urticaria have occurred.
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.
Learn more about Angioedema by listening to the “All Things Angioedema”-Podcast series via Spotify or Apple Podcast.
Forms of Urticaria
Urticaria is classified as acute or chronic according to its duration and as inducible or spontaneous according to the role of certain triggers. Acute urticaria is characterized by the occurrence of wheals and/or angioedema lasting 6 weeks or less. While most cases of acute urticaria resolve within 1 week, less than 40% of cases become chronic.
Chronic urticaria is defined as the occurrence of wheals and/or angioedema for more than 6 weeks. In the course of chronic urticaria, daily or almost daily symptoms or frequent symptom-free periods, that may even last for weeks or years, can occur. As a frequent clinically significant variant, chronic urticaria is subdivided into spontaneous (chronic spontaneous urticaria/CSU) and inducible (chronic inducible urticaria/CIndU) subtypes.
Learn about acute urticaria by watching the UCARE 4U video about this topic or in the “Triggers and Types” page of this FAQ.
Learn about chronic urticaria by watching the UCARE 4U video about this topic or in the “Triggers and Types” page of this FAQ.
CSU
The spontaneous form of chronic urticaria, also known as chronic spontaneous urticaria (CSU) is characterized by the sudden (out of the blue) appearance of itchy wheals, angioedema, or both in the absence of a definite trigger. Yet, various unspecific triggers have the potential to cause flare-ups or to worsen CSU including non-steroidal anti-inflammatory drugs (Diclofenac, Ibuprofen or ASS) or stress.
The UCARE experts from Global Allergy and Asthma Excellence Network explain more about CSU in the UCARE 4U video about chronic urticaria.
CIndU
The inducible form of chronic urticaria, also known as Chronic Inducible Urticaria (CIndU), is characterized by the appearance of itchy wheals, angioedema, or both in the presence of a definite subtype-specific trigger.
Wheals and/or angioedema always occur when the trigger is present and never when it is absent. Each sub-form of 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), thermal urticaria (heat), vibratory angioedema (vibrations), cholinergic urticaria (increase in body core temperature), contact urticaria (skin contact with triggering agents) and aquagenic urticaria (water).
The UCARE experts from Global Allergy and Asthma Excellence Network explain more about CIndU in the UCARE 4U video about physical urticaria and in the UCARE 4U Webinar No. 4: Inducible Urticaria – How to test and what to expect?
Learn more about the different forms of CInDU on the page “Triggers and Types” of this FAQ.
The Course of Urticaria
How does Urticaria develop?
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 results in the release of messenger substances such as histamine, causing itching, redness, and swelling. Acute urticaria can arise from various factors, including allergies or acute infections. However, in most cases, the exact cause remains unidentified. We also do not know yet, how acute urticaria develops into a chronic urticaria. Known types of chronic urticaria either appear in response to a definite subtype-specific trigger (CIndU) or in the absence of a definite trigger (CSU).
What is the prognosis?
While most cases of acute urticaria resolve within 1 week, even without treatment. less than 40% of cases become chronic. However, almost 50% of affected people are symptom-free within 1 year.Dependet on the type of chronic urticaria (CU), the time to resolve may strongly vary. In some cases, CU may last for several years before spontaneous remission with the possibility of waxing and waning of symptoms from time to time.
In general, many patients with chronic urticaria respond well to antihistamines alone and have a favorable prognosis and outcome. Importantly, disease control of CU is best achieved by antihistamines when taken regularly and discontinuation for a treatment on demand may be one reason for common treatment failure.
Can Urticaria become dangerous?
The good news is that urticaria is a benign condition as it is not life-threatening, not contagious, and is easily treatable in most people. However, 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 emotional distress, and possibly leading to depression. 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.
Most cases of acute and chronic urticaria are non-allergic and, although bothersome, 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. Avoidance of any known trigger of your urticaria is the most crucial step to avoid recurrence in the future.
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