What is it?
It is a common skin rash which cause is alergic. Its main characteristic is the appearance of elevated and reddish plaques on the skin, accompanied by intense itching.
It can occur at any age and triggering factors usually involved are medicines, food, inhaled substances (perfumes, dust, insecticides, deodorants), infections and physical agents (cold, heat or pressure).
Triggering factors activate mast cells (a special type of cell present in the skin), which release substances which are responsible for the symptoms, primarily histamine.
Characteristics and symptoms
Urticaria may be acute, when the lesions disappear after a few hours or days, or chronic when they persist for several weeks.
In acute urticaria, generally, the condition is more intense. The lesions vary from small red spots to larger plaques, reddish and swollen, which may join affecting large areas. The lesions tend to be of short duration, disappearing and appearing again in other locations. The entire skin surface can be affected and pruritus (itching) is usually very strong.
There is a type of hives that manifests itself in a very intense form, called Quincke's edema, which main feature is the edema (swelling). Often appears in the face, with intense edema of the lips and eyelids. This form may be dangerous if the swelling reaches the larynx, leading to breathing difficulty and asphyxiation.
In chronic urticaria, the condition is less intense, but long lasting. The lesions tend to be smaller and may be continuously present or disappear for a period to reappear later.
Specific forms of urticaria that is worth mentioning are:
- Dermographism, in which linear lesions are formed after rubbing the skin (photo below);
- Pressure urticaria, which form lesions in skin areas that suffer continued pressure (for example: bra or elastic pants);
- Cold urticaria, in which lesions arise after exposure to cold (sea bathing or swimming pool with cold water).
The treatment of urticaria initially aims to combat the symptoms caused by the action of histamine, and therefore, antihistamines are the drugs indicated. Products for local use, with menthol and camphor, may help relieve itching.
In the case of Quincke's edema, medication should be initiated urgently and may require the use of corticosteroids, in addition to antihistamines, to prevent the swelling of the larynx.
In the case of chronic urticaria, in addition to symptomatic medication, it is important to discover what is causing the hives. However, often the cause remains unknown. It is noteworthy that even emotional phenomena may cause or prolong the disease.
- Contact dermatitis
- Atopic dermatitis