Urticaria causes (hives)

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Urticaria (or hives) are a kind of skin rash notable for dark red, raised, itchy bumps. Hives are frequently caused by allergic reactions, however there are many non-allergic causes. For example, most cases of hives lasting less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) are rarely due to an allergy. The majority of patients with chronic hives have an unknown (idiopathic) cause. Perhaps as many as 30-40% of patients with chronic idiopathic urticaria will, in fact, have an autoimmune cause. Acute viral infection is another common cause of acute urticaria (viral exanthem). Less common causes of hives include friction, pressure, temperature extremes, exercise, and sunlight. It may be true that hives are more common in those with fair skin.

The skin lesions of urticarial disease are caused by an inflammatory reaction in the skin, causing leakage of capillaries in the dermis, and resulting in an edema which persists until the interstitial fluid is absorbed into the surrounding cells.

Allergic urticaria
Histamine and other pro-inflammatory substances are released from mast cells in the skin and tissues in response to the binding of allergen-bound IgE antibodies to high affinity cell surface receptors. Basophils and other inflammatory cells are also seen to release histamine and other mediators, and are thought to play an important role, especially in chronic urticarial diseases.

Autoimmune urticaria
In the past decade, it has been noted that many cases of chronic idiopathic urticaria are the result of an autoimmune trigger. For example, roughly one third of patients with chronic urticaria spontaneously develop auto-antibodies directed at the receptor FcεRI located on skin mast cells. Chronic stimulation of this receptor leads to chronic hives. Patients often have other autoimmune conditions such as autoimmune thyroiditis.

Non-allergic urticaria
Mechanisms other than allergen-antibody interactions are known to cause histamine release from mast cells. Many drugs, for example morphine, can induce direct histamine release not involving any immunoglobulin molecule. Also, a diverse group of signaling substances called neuropeptides have been found to be involved in emotionally induced urticaria. Dominantly inherited cutaneous and neurocutaneous porphyrias (porphyria cutanea tarda, hereditary coproporphyria, variegate porphyria and erythropoietic protoporphyria) have been associated with solar urticaria. The occurrence of drug-induced solar urticaria may be associated with porphyrias. This may be caused by IgG binding not IgE.

Stress and chronic idiopathic urticaria
Chronic idiopathic urticaria has been anecdotally linked to stress since the 1940s[1]. There is a large body of evidence demonstrating an association between this condition and both poor emotional well-being[2] and reduced health related quality of life[3]. More recent research has investigated hypotheses about stress as a causal factor in triggering the condition. Evidence has been found for a link between stressful life events (e.g. bereavement, divorce etc…)[4] and preliminary evidence has been reported for a link between posttraumatic stress and chronic idiopathic urticaria[5]. Less is known about the individual experiences and characteristics of people who develop chronic idiopathic urticaria following stress. Research into these factors in the relationship between stress and chronic idiopathic urticaria is ongoing by a number of researchers, including an online project[6] currently being undertaken by researchers at the University of Plymouth

Anaphylaxis – the most dangerous allergic reaction

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The most famous and dangerous allergic reaction is anaphylaxis. Anaphylaxis is a severe, whole-body allergic reaction. After an initial exposure (“sensitizing dose”) to a substance like bee sting toxin, the person’s immune system becomes sensitized to that allergen. On a subsequent exposure (“shocking dose”), an allergic reaction occurs. This reaction is sudden, severe, and involves the whole body.In cases of anaphylaxis systemic reactions occur in just minutes and are characterized by breathing difficulties and circulatory shock that can be avoided only through injections of adrenaline and cortisonici.

The events of anaphylactic shock are:

* the pressure drop
* paleness
* tachycardia
* sweating
* angioedema inland areas above
* difficulty breathing
until you reach the circulatory collapse and death.
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Eczema (atopic dermatitis)

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Eczema or atopic dermatitis is an allergic disease, subject to hereditary influences mediated by antibody awareness that the skin and may be associated with bronchial asthma, allergic rhinitis, hives.

Causes

Usually starts in the infant to the 2nd or 3rd month of life, an important role in the development of the reaction are the environmental factors (hot, cold, rapid temperature changes), or household, such as house dust, animal hair of animals and certain foods, fatigue and emotions. The events affecting the face, then stretch the neck, the hands, wrists and may be widespread. Normally 2 years to resolve spontaneously without leaving outcomes. To 6 years can reappear in the same locations, with events that can be resolved by themselves after a few years and reappear again during puberty (in this period, the main cause of deterioration is represented by emotional stress) located mainly in the flexor surface of the limbs. When in adulthood, and is defined constitutional eczema of adults, can occur without being preceded by the child.

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Home Environment -how to remove mites from your house

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-The house (especially the bedroom) should not be too hot (not exceeding 20 ° C) must be ventilated long during the day, even in winter. The humidity environments must be maintained no more than 40 — 50%, avoiding the use of heaters and humidifiers on environmental, channeling the steam bath and kitchen outside the windows.

– Keep the house in fewer plants.

- Extremely useful for environmental remediation is the use of acaricides and denaturing of the Mite Allergen spray periodically by the cushioning material on rugs or carpets. Tra quelli in commercio si è aggiunto recentemente , come insetticida, un derivato sintetico non tossico del piretro . Among those on the market was added recently, such as insecticide, a derivative of non-toxic synthetic pyrethrum.

- Must not be used, and possibly removed if already present, pillows, chairs and upholstered furniture containing materials of animal or plant origin such as kapok, hemp, hair vegetable, hay, straw, wool, feathers, cotton, jute, etc..

- Hamsters and other small rodents, dogs, cats and birds should not be kept at home. The animals already have to be removed or kept scrupulously clean .
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