October 1 marks World Urticaria Day: up to 20% of the population may be affected

October 1st marks World Urticaria Day, a disease that can affect up to one in five people over the course of their lives.

According to immunoallergologist Sofia Campina of SPAIC (Portuguese Society of Allergology and Clinical Immunology), urticaria is a clinical condition characterized by the appearance of reddish spots or papules, raised in relation to normal skin, which cause intense itching and disappear momentarily when pressed. Urticaria manifestations can appear all over the body or in specific areas, with each spot/papule lasting from a few minutes to several hours (no more than 24 hours) and leaving no marks on the skin.

Regarding its classification, a distinction is made between acute and chronic urticaria. Acute urticaria—which lasts a maximum of six weeks—"is the most common, occurring in 10 to 20% of the population at least once in their lifetime and, in most cases, associated with an infectious condition," says Sofia Campina.

Chronic urticaria—where skin lesions and itching appear and disappear daily for more than six weeks in a row—can be divided into two types: inducible and spontaneous. Chronic inducible urticaria is triggered by a specific stimulus (such as cold, friction, increased temperature, or exercise), while chronic spontaneous urticaria causes skin lesions to appear without a specific identified stimulus.

"An individual may have more than one form of urticaria, that is, have spontaneous manifestations and also manifestations with specific physical factors," explains the specialist.

Among the main causes of the development and worsening of urticaria, Sofia Campina explains, "is an exaggerated response by certain cells in the skin that frequently and unpredictably release substances that cause itching (histamine and other inflammatory substances). Most of the time, the cause is unknown and may involve an immune system reaction. Stressful situations, infections, certain medications (such as anti-inflammatories), and even hormonal fluctuations can lead to worsening episodes of chronic spontaneous urticaria."

The diagnosis of urticaria is clinical, based on the observation of skin lesions: spots, papules and/or swellings and the history of characteristic symptoms, "since there are no specific tests to confirm the disease", says the immunoallergologist who also adds the importance of, when suspected of chronic spontaneous urticaria, "having follow-up in an Immunoallergology consultation".

Treatment involves antihistamines: medications that block the action of excess histamine release. However, in more difficult-to-control cases, "antihistamine dosage adjustments and even more specific treatments that reduce the immune system's overactivity are necessary, always in consultation with a specialist doctor," concludes Sofia Campina.