Urticaria: causes and remedies

It can be chronic or acute, and the cause is often not recognized. Here’s how to diagnose and treat hives.

A rash, localized or diffuse, due in some cases, but not always, to allergic mechanisms and characterized by raised bumps associated with itching and swelling. This is urticaria, a dermatitis that can be attributed to various causes, but in some cases remains unexplained.

Urticaria, what is it?

Urticaria is an inflammatory response of the skin caused by the release of histamine by the immune system. The itchy bumps and raised spots are in fact due to the action of this chemical substance released by mast cells, the cells of the immune system responsible for defending the body from allergens and infectious agents.

Contact with an allergen, as well as a stress resulting from heat, cold, viruses or drugs, causes mast cells to activate and histamine to be released, which in turn induces blood vessels to dilate.

This causes the leakage from the vessels of the aqueous component of the blood that goes to swell the dermis giving rise to the bump. In addition, for relaxation of the vessels, blood is brought to flow closer to the epidermal surface, hence the red color of the lesions.

Many types of urticaria

Urticaria is divided into two broad categories, depending on the duration of skin manifestations. Acute urticaria occurs when symptoms last less than six weeks and the cause is easily detected.

Rashes lasting more than six weeks suggest the diagnosis of chronic urticaria, which in turn can be classified into:

• chronic inducible urticaria, when there is a known external trigger
• chronic spontaneous urticaria, when it is not possible to identify a factor that led to the onset of symptoms.

In two out of three cases, chronic urticaria is spontaneous, therefore unpredictable in terms of both onset and duration. In most cases the duration varies between 1 and 5 years, but longer crises are also possible, with important consequences on the quality of life of those who suffer from them.

It is estimated that 20% of the population has had at least one episode of acute urticaria in their lifetime. Chronic urticaria, on the other hand, affects 1% of the population (women twice as much as men) and occurs mostly between 20 and 40 years of age.

The causes of urticaria

Acute urticaria is due in most cases to a skin reaction caused by exposure to a drug, allergen or physical stimulus. It is not uncommon, however, that it is difficult to identify the triggering factor, and therefore that the episode remains without apparent cause. In addition, it can happen that an allergy to a previously tolerated substance suddenly develops.

The categories of drugs most often responsible for the onset of skin manifestations are antibiotics and NSAIDs (non-steroidal anti-inflammatory drugs), a category to which some analgesics, painkillers, anti-inflammatory and antifebrile belong. In these cases the reaction appears within 48 hours of intake.

The appearance of urticaria can then be linked to external factors such as stress, heat, sunlight, sun exposure. Agents responsible can also be cold, water, physical exertion, rubbing and pressure on the skin.

To trigger allergic reactions that can cause hives is the ingestion of certain foods such as peanuts, nuts, fish, molluscs, crustaceans, wheat, eggs and milk.

Also pay attention to foods rich in histamine. In predisposed individuals, especially those suffering from histamine intolerance, certain foods can cause symptoms including hives. Here are the main ones.

Other possible triggers can be insect bites and viral or bacterial infections, typically tonsillitis or streptococcal pharyngitis, especially in children.

There is also the possibility that urticaria is triggered by the reaction to contact with certain substances: latex, saliva or animal dandruff, dust, pollen or mold.

A particular case of urticaria is dermographism, a disorder characterized by an abnormal reaction of the skin to a mechanical stimulus. Redness and sudden swelling that are highlighted when exerting pressure on the skin are the characteristic manifestations of dermographism. In the most serious cases, following the stress of the skin with a non-sharp object, a sort of design composed of a sequence of bumps can be formed, so it is as if it were possible to “write” on the skin, hence the name dermographism.

In the case of a chronic form of urticaria, it is caused in most cases by the same drugs that trigger acute episodes or external, physical and emotional factors (cold, exposure to the sun, water, etc.).

However, possible causes also include cancers and autoimmune diseases, such as systemic lupus erythematosus, Sjögren’s syndrome, urticarial vasculitis and thyroid disorders. Chronic spontaneous urticaria can be confused with an allergy, but it cannot be classified as such because it is not possible to identify an external stimulus that determines it.

The disease can regress spontaneously and reappear suddenly; This dynamic is a cause for anxiety and concern for people who are affected, who see their quality of life seriously compromised with repercussions on social relationships, school and work performance and psychological well-being.

Rarely chronic spontaneous urticaria is due to the ingestion of a food; However, when the factor that triggers urticaria is not known, it may happen that the patient unnecessarily modifies his diet by gradually excluding one or more foods.

Symptoms of urticaria

The symptoms that distinguish urticaria are bumps and angioedema, which in some cases can occur simultaneously.

The bumps are eruptions with a red or pink color and a roundish shape. They appear in variable numbers and can also take irregular shapes, overlapping and giving rise to lesions that affect a larger surface of the body. The bumps are accompanied by itching, and their appearance may be preceded by a burning sensation.

The bumps appear within a few hours of the stimulus and can have a variable duration, from a few minutes up to, more rarely, 24-48 hours. It is also possible that, after disappearing, they reappear in another location.

The itching can be more or less intense depending on the site affected by the rashes and the time of day. Manifestations on the scalp and palms of hands and feet are more annoying. The heat and humidity also aggravate the symptoms. The continuation of the disorder with intense symptoms can cause the onset of states of anxiety and depression.

Sometimes the bumps are associated with angioedema, a swelling of the subcutaneous area that occurs in correspondence of the areas around the eyes and mouth, on the genitals, hands and feet. It can last up to three days and is accompanied by a sense of tension. Angioedema can also affect the intestine and in this case cause abdominal pain. If it affects the larynx and tongue, causing it to swell, it can obstruct the airways and cause a feeling of suffocation.

Diagnosis

Diagnosis of urticaria is made by the dermatologist. It is incorrect instead to rely on DIY or different specialists because, even if at the base there could be a cause of an allergic or immunological nature, it is still a skin disorder.

In the case of chronic urticaria, diagnosis is usually late, and often the patient requires the consultation of various specialists before reaching it.

To diagnose urticaria, physical examination and collection of information about the patient’s history are necessary. A blood test can also be useful, which can give information on a possible inflammatory pathology underlying the disorder. The assay of immunoglobulins E (IgE) provides information on the presence of allergies.

If the doctor suspects the inducible nature of urticaria, or with a defined cause, he will subject the patient to specific tests such as the application of heat or cold on the skin or mechanical pressure to verify if it is a form of dermographism.

In cases of chronic spontaneous urticaria, allergy tests generally have negative results and even the dosage of IgE is not useful, as it is normal.

For the purpose of diagnosis, in an attempt to identify which factors trigger the disorder, it may be useful to keep a diary in which to note the characteristics of the episode (where and when it occurs), details of one’s diet and activities, as well as the possible intake of medications.

Treatment of urticaria

Antihistamine drugs are the basis of symptomatic therapy, while remedies for local use such as ointments and ointments are not effective.

The use of cortisone is not recommended: in addition to causing side effects, it can cause chronic urticaria. In the event of an attack, in fact, the body is activated to block the effect of histamine; If cortisone is taken at that time, the urticaria regresses, but the result is to simultaneously block both the factors that maintain urticaria and those that counteract it. At the suspension of the drug there is then the resumption of the manifestation.

One treatment that has been shown to allow healing from urticaria is based on a calcium channel blocker with antihistamine activity. The therapy consists of monthly cycles of 21 days interspersed with a one-week suspension.

Other categories of useful drugs are antiserotoninics or antileukotrienes.

In recent years the therapeutic possibilities for the treatment of chronic spontaneous urticaria have expanded thanks to the approval of a new biological drug, already used for severe bronchial asthma, which has given positive results, with good control of symptoms.