Profile: Urticaria.

Definition:   A common skin eruption characterised by the appearance of slightly raised red-pink patches on the skin. These are often accompanied by itching. The reaction is due to the activation of a cell in the immune system: the mast cell, which releases histamine, a molecule involved in triggering inflammatory reactions. Urticaria can be acute (when the patches remain for a few hours to a few days and do not return) or chronic (when the lesions persist beyond 6 weeks and occur every day or every other day).

Internal and external causes:   Allergies to certain foods high in histamine, histamine-releasers or rich in tyramine (fermented drinks, eggs, chocolate, peanuts, seafood, fruits, food additives...); direct contact with plants (nettles...), animals (jellyfish, animal hair...) or a material (latex, wool...); infection; medications (aspirin, non-steroidal anti-inflammatory drugs, morphine, codeine...); underlying diseases (autoimmune thyroid diseases, rheumatism, otitis, rhinopharyngitis, angina, etc.); emotional and/or psychological events (stress, anxiety, depression); skin friction; sun; heat; pneumallergens (pollens, moulds, dust, animal dander...).

How to reduce or eliminate them:   Apply a cold compress to the affected areas to reduce itching; consult a doctor; medicinal treatments (antihistamines, corticosteroids, immunosuppressants).

Preventive measures:   Limit exposure to the triggering allergen or irritant (pollen, dust mites, animal hair...); apply moisturising creams to reduce skin dryness and limit irritations; check the labelling of products to ensure they do not contain substances that could trigger an allergic reaction; undergo allergy tests to identify allergens to avoid; avoid wearing tight clothing; avoid any exposure to the sun without suitable sun protection.