Symptoms and causes are not always clear: here is a profile of one of the most debilitating skin conditions

“More knowledge. Better skin health.” The slogan for World Skin Health Day, celebrated on 8 July – on the initiative of the International League of Dermatological Societies and the International Society of Dermatology —shines a spotlight on the importance of accurate information and prevention regarding the wide range of conditions and symptoms that can affect our largest organ: the skin. This is also why it is among the organs most exposed to both external and internal ‘aggressions’. Among the most significant conditions are urticaria, skin rashes with multifactorial causes. What we refer to as urticaria is an immuno-allergic reaction of the skin, the causes of which can be many and varied. The symptoms include a rash characterised by wheals – that is, raised areas of skin that are flat on top and have a raised edge – which appear and then usually disappear after a few hours, only to possibly recur without any clear ‘reason’.

As well as hives, symptoms include itching and swelling, sometimes affecting the lips and eyes, and very rarely the windpipe, leading to a feeling of shortness of breath. Urticaria is extremely common: half the world’s population experiences at least one episode in their lifetime; chronic spontaneous urticaria is less common but, even so, in Italia alone it affects around 480,000 people, with a 2:1 ratio of women to men and an estimated prevalence of around 0.8 per cent, mostly among young adults aged between 20 and 55.

Within the family of urticaria, the most obvious clinical distinction is between the acute and chronic forms. The former occurs in a patient who has never had it before – or who has been symptom-free for years –: it may present as a single episode or even as several repeated episodes, which in any case disappear within three months. These acute forms often have a clearly identifiable cause: they are allergic or allergo-toxic in nature, caused, for example, by a medicine or a food preservative, or by an environmental trigger. The ‘reaction’ only subsides once the person is no longer exposed to these factors.

Chronic forms of urticaria are more difficult to investigate because they can have a wide range of causes, often requiring the patient to undergo a comprehensive series of tests, yet in the majority of cases the cause of the condition remains unidentified. This is then referred to as idiopathic urticaria: when the cause simply cannot be traced.

“In the case of acute urticaria,” explains Sidemast President, Giovanni Pellacani – we can often trace the cause back to a preservative or a medicine, or even to heavy exposure to very dusty environments that triggered it; for chronic cases, however, allergic causes are far less common. Behind the chronic form,” the expert warns, “there may be immunological abnormalities such as autoantibodies, the body’s immune responses, or even an increased release of substances that cause urticaria by mast cells – the mediator cells that are more sensitive, meaning that a physical stimulus such as heat, cold or rubbing is enough to trigger the release of the substances underlying the urticaria”. Any latent chronic infections – for example, in a tooth or the gallbladder – should also be investigated, as these do not cause any actual symptoms but may nevertheless trigger the immune response underlying the condition.