The name Urticaria has originated from the famous European stinging nettle Urtica dioica. The condition is mainly characterized by the appearance of very itchy hives (weals) with or without presence of adjacent erythematous flares. It can be either acute, inducible, or spontaneous.
A weal is defined as a superficial skin swelling which appears as skin-coloured or pale. It is usually surrounded by erythema that can last from couple minutes to an entire day.
Urticaria is classified into acute and chronic urticaria, depending on its duration. Acute urticaria lasts less than 6 weeks and usually disappears within few hours to days. Chronic urticaria, which can be either inducible or spontaneous, lasts more than 6 weeks with daily or episodic occurrence of weals.
One in five children or adults will get an episode of acute urticaria during their lifetime. All sexes are equally affected.
Acute urticaria can affect newborns and infants; however, these cases are quite rare. Usually, acute urticaria is caused by infection in children. In older children, other factors like medication, food, and inhaled allergen can trigger this condition. In adults, idiopathic and spontaneous urticaria is more prevalent.
Acute urticaria accompanied by fever can be the first sign of COVID-19 infection.
Chronic spontaneous urticaria (CSU) is more prevalent in women- 2/3 of all reported cases. Overall, 0.5-2% of the general population is affected.
In comparison with chronic spontaneous urticaria, chronic inducible urticaria is more common.
Urticarial weals have the following clinical features: they vary from a few millimeters to centimeters in diameter; can be red or white, and may or may not include a red flare. Weals may appear as giant patches, round, or form rings.
Chronic spontaneous urticaria is assessed via the UAS7 scoring system. The daily weal/itch scores are added together for seven days. The maximum awarded score is 42.
The emotional aspect and its effect on the quality of life should also be assessed. The Dermatology Life Quality Index (DLQI) and CU-Q2ol have commonly used questionnaires.
Weals are triggered by the release of chemical mediators, such as cytokines, histamine, and platelet-activating factor, from circulating basophils and tissue mast cells. These mediators facilitate sensory nerves and result in dilation of blood vessels and leaking of fluids into surrounding tissues.
Different hypotheses have been proposed to explain the causes of urticaria. Arachidonic acid, immune system, and coagulation systems are the primary agents that can cause this condition. However, further studies are needed to be done in order to determine which genetic mutations are responsible for causing urticaria.
Urticaria is diagnosed in patients who have a history of weals lasting less than 24 hours with or without angioedema. Family history and history of medication should be assessed. A careful physical examination should take place.
If food, drug, or latex allergy is suspected in acute urticaria, the patient will be referred for additional tests like skin prick tests and radioallergosorbent tests (RAST).
The primary treatment method of Urticaria administered to adults and children is an oral second-generation H1-antihistamine (e.g., loratadine or cetirizine).
Generally, acute urticaria should resolve within hours to days but can re-occur in the future. Chronic urticaria usually clears up; however, in 15% of cases wealing can be observed twice weekly after two years.
Centre for Medical and Surgical Dermatology offers different Urticaria treatments unique to each patient.
