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Hives : Definition, Causes, Symptoms, Diagnosis and Treatment

Wednesday, August 22nd 2012. | Allergy, Disease, Skin, Hair and Nails

Hives Definition

Urticaria is a rash that takes the form of red patches flat or raised, without injury to the skin.

Each plate or of the papule uricaire has a size, shape and appearance can vary from a few millimeters to several centimeters. The papules may be confluent (it is then giant urticaria).

Urticaria is accompanied by severe itching. Plates usually disappear without a trace in less than 24 hours. But others may occur simultaneously or sequentially. In total, the rash may persist for several days. It is acute urticaria. Beyond one month, it is called chronic urticaria.

Urticaria is a very common condition with 15 to 20% of the population is one day face this problem. The origin of the hives is usually found only in 50% of cases.



Angioedema is a severe hives. The eruption took place under the skin is white and edema without itching. The risk of angioedema is its location in the larynx (located at the front of the neck) then there is risk of suffocation.

Anaphylactic shock

Outside angioedema, urticaria alone presents no danger.However, urticarial rash, sudden onset accompanied by other signs (difficulty breathing, abdominal pain, diarrhea, malaise) must dread the onset of anaphylactic shock (allergic) and require emergency

What Mechanism?

The formation of the wheal of urticaria occurs in response to the appearance of vasoactive substances (active vessels) at the site of injury. These substances (mainly, but not exclusively, histamine) will cause dilation of blood vessels, swelling, redness and pruritus (itching).

Histamine and other mediators may be released from cells that contained either an immunological mechanism (defense reaction) or directly without cause found. The active ingredients may also be made through diet or be included in medicines, poisons, infectious agents. Many factors can cause an urticarial rash.

Hives Causes

The causes are multiple.

Some causes are linked to an external factor to the body:

Other causes of hives are related to diseases (endocrine damage, disease called systemic issues affecting the whole body). Finally, it is very often no cause is found (in about 50% of cases according to some statistics).

Hives Food Causes

This case is common and easy to identify.

The food allergic urticaria is relatively easy to identify if the crisis is isolated and each recurrence of the same food intake. However cofactors can interact and modulate the body’s response to food.

The person does not necessarily react in the same way each time, which makes the diagnosis more difficult. All foods can be responsible for allergic reactions hives, but with a variable frequency. In cases of chronic urticaria, only the dietary survey can help solve the problem.

An attack of acute urticaria must seek the triggering agent in food (and / or drugs) ingested immediately before the crisis. The time to onset of symptoms varies from a few seconds (for mouth rashes) to 5 hours. Therefore remember all food during this period of time, not to mention the spices and condiments.

To demonstrate the responsibility of the food, it is necessary to perform skin tests by an allergist, to test eviction or even provocation tests. If the hives was violent, it is advisable to carry out the tests reintroduction hospital.

In case of chronic urticaria (hives daily for more than a month), food is rarely involved and more difficult incrimination. Keeping a notebook food (dietary survey) containing a list of all food for 8 days can help find the cause. The analysis of these specifications will select foods tested.

Foods implicated in the majority of cases are of plant origin, After food of plant origin, followed by eggs and fish. In fact, any food may cause food allergy …

Study Circle clinical and biological investigations in food allergy (CICBAA) clarified the frequency range of foods that cause food allergies in France.

Adults : allergens plants (fruits and vegetables) account for 84% of cases of food allergy. The incidence increases with age, probably in conjunction with the acquisition of pollen sensitization. They are in descending order:

  • Rosaceae (apple, peach, pear, cherry, plum, nectarine, apricot): 15.4% :
  • The group “latex”: avocado, kiwi, banana, chestnut: 14.3%  ;
  • The group of Umbelliferae (celery, carrot, parsley, dill, coriander, fennel): 11%   ;
  • Nuts (almonds, hazelnuts, walnuts, cashews, pecans):7.3%  ;
  • Egg whites with protein allergens are ovalbumin (64%), conalbumin (14%), ovomucoid (9%), the ovoglobulin (9%) and lysozyme (3.4%): 4.7%   ;
  • Sesame: 4.4%  ;
  • Peanut: 4.3%  ;
  • Crustaceans;
  • Fish;
  • The group qu’arachide other legumes: lentil, pea, soybean, lupine, chickpea, bean, garlic, wheat, sunflower;
  • The group meat: beef, chicken, turkey, duck, pig, rabbit
  • The group cereals other than wheat rye, oats, malt, barley, spelled.

Descending the foods most often cause urticaria in children are:

  • Egg: 34.2% ;
  • Peanut: 22.9% ;
  • The milk  8.1% ;
  • Mustard: 5.8% ;
  • Fish: 4.7% ;
  • Group legumes other than peanut lentils, peas, soybeans, lupine, chickpea, bean: 2.87% ;
  • 2.6% group nuts: almonds, walnuts, hazelnuts, pistachios, pine nuts, Brazil nuts, cashew nuts, pecans;
  • Group 2.46% meat: beef, chicken, turkey, duck, pig, rabbit.

Hives Treatment

The treatment of choice is based on antihistamines. The new latest generation molecules are effective and well tolerated, not soporific. They are active in acute urticaria and a large proportion of chronic urticaria. In some cases they are insufficient and should add other medications vary depending on the case.

The best treatment remains on allergen avoidance.


The hereditary angioedema occurs with more severe intestinal disease and laryngeal common, more skin edema. Digestive symptoms resemble those of a bowel obstruction and may cause the patient to surgery.

The combination of visceral and cutaneous edema should suggest the diagnosis, especially since it is a family affection. In this condition there is a deficiency of a molecule needed to run certain immune responses (inhibitor of complement).

The specific treatment should be implemented by specialized teams.

Hives Questions

How long will this last?

Everything depends on the cause of the rash. In case of acute urticaria with officer identified and removed, everything works quickly. In case of chronic rash without cause found, it is impossible to predict the duration of evolution. It may be a few months to a few years without knowing why.

Is this serious?

Urticaria is a disease generally benign. The eviction of the cause, if known, always brings healing. Sometimes a crisis of acute urticaria is the first symptom of an allergic reaction (anaphylaxis). Then there is possibility of involvement of other events: asthma, abdominal pain and discomfort especially with voltage drop. This is anaphylactic shock, requiring emergency care.

Is there a cure?

Healing hives depends exclusively on the removal of the cause if possible. Treatments are suspensive : they relieve, but the cause is still present, there recurrence after discontinuation of treatment. For urticaria, the cause has not been identified, the course is variable and unpredictable, but there are many spontaneous healing. Sometimes a habituation occurs.


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