Hives: What It Is, Causes, Symptoms, and Treatment

Urticaria, also known as hives, is a type of skin reaction that causes redness, itching, and welts on the skin. Although it is commonly associated with allergies, hives can be triggered by many different causes and can occur in both acute and chronic forms. Acute urticaria (lasting less than 6 weeks) is much more common than chronic urticaria (lasting more than 6 weeks). In addition to urticaria, swelling known as angioedema may also occur. Angioedema generally appears around the face and lips but can also appear anywhere on the body. Acute hives usually occur without an underlying disease and are short-lived. However, they can cause significant discomfort, including burning and itching, which can affect sleep and quality of life, making treatment necessary. If the condition becomes chronic, individuals experience these symptoms for a longer period, and they may worry about when the condition will end. In such cases, underlying diseases need to be investigated. Anyone with long-term or suddenly severe hives should seek consultation from a dermatologist and begin appropriate treatment.

What is Hives?

Hives are characterized by raised welts on the skin, which can appear due to various reasons or without an underlying cause, leading to itching and redness. Up to 20% of people may experience at least one episode of hives in their lifetime. The welts can vary in size, from a few millimeters to several centimeters. They appear suddenly and typically fade quickly. If the hives become chronic and resistant to conventional treatments, further investigations and more advanced treatments may be required.

Hives in Children
Urticaria can occur at any age, from infancy to adulthood. In children, it can develop during frequent infections, the presence of intestinal parasites, or the use of certain medications, especially in those with atopic (allergic) tendencies. In cases of severe hives accompanied by angioedema (swelling), it is essential to seek medical attention.

Hives in Adults
In adults, urticaria can occur alone or together with angioedema and is quite common. It is twice as frequent in women compared to men. Approximately 20% of the population will experience hives at some point in their lives. Most cases are acute urticaria, which responds well to classic antihistamine treatment. Allergy tests can help identify triggers, and avoiding these triggers can be effective in reducing hives in adults.

What Are the Symptoms of Hives?

Urticaria, which develops suddenly and leads to itching and welts, causes symptoms that are easily noticeable. The most common symptoms of hives include:

• Mild or severe itching/burning/stinging
• Raised welts on the skin, ranging in size from less than 1 cm to over 8 cm
• Redness on the skin
• Angioedema (swelling)
  Angioedema, or swelling, can occur along with hives. Unlike urticaria, these are reactions that appear in the deeper layers of the skin. In acute urticaria, these symptoms typically disappear within a few hours. In some cases, they may persist for several days. In chronic urticaria, flare-ups may occur at various intervals and can last for years.

What Causes Hives?

Urticaria occurs when the body produces histamine and other chemicals under the skin due to various reasons. These substances cause fluid buildup under the skin, forming welts. The severity of the reaction varies from person to person. Although urticaria is often known as an allergic reaction, allergy is not a common cause of hives. While most cases are idiopathic (with no known cause), infections, medications, and rarely, foods can trigger hives. Some factors that can cause hives include:

• Infectious diseases
• Certain foods (especially peanuts, shellfish, nuts, celery, eggs, strawberries, milk, and dairy products)
• Antibiotics, anti-inflammatory drugs, and other medications
• High fever
• Exposure to hot environments and sudden changes in environmental temperature
• Pollen
• Animal hair and secretions
• Dust mites and mold
• Latex
• Insect waste and insect bites
• Certain chemicals such as creams, perfumes, and cleaning products
• Intense physical exercise
• Contact with fluids such as water, tears, or sweat
• Sunlight
• Intestinal parasites
• Autoimmune diseases such as thyroid disorders or systemic lupus erythematosus

In many cases of hives, the exact trigger cannot be determined. Aside from insect bites or the consumption of unusual foods or medications, there may be many different causes for hives. Allergy tests only screen for a limited number of allergens, so the cause of urticaria may not always be identified. However, in cases of hives known to be triggered by an autoimmune response, the treatment protocol remains generally similar regardless of the cause.

What Are the Types of Hives?

Urticaria has two different subtypes based on the duration of the condition. The first subtype is acute urticaria, which lasts less than 6 weeks, subsides within hours without leaving any marks, and can reappear with welts of varying sizes. Chronic urticaria, on the other hand, lasts more than 6 weeks and can fluctuate, becoming less severe and then flaring up at various periods. This type of hives can develop either spontaneously (chronic spontaneous urticaria) or after exposure to a specific trigger (chronic inducible urticaria) such as heat, cold, friction on the skin, exercise, etc. For instance, if it is triggered by cold, it is called cold urticaria; if triggered by exercise and increased body temperature, it is called cholinergic urticaria. These types are not entirely separate, and they can coexist in the same patient. The chronic urticaria types based on physical triggers are as follows:

Symptomatic Dermographism
This type of urticaria is characterized by linear welts that appear after the skin is scratched with a sharp object such as a needle, pen tip, or nail. Symptoms tend to worsen in the evening, and the lesions typically disappear within one hour. There is no association with systemic diseases, atopy (allergic conditions), or food allergies.

Delayed Pressure Urticaria
This type of urticaria occurs after pressure is applied to any part of the body, typically causing itchy and painful welts. It significantly affects quality of life and is resistant to treatment. Symptoms develop after a period of 30 minutes to 12 hours following pressure application. This type of urticaria can develop after wearing tight clothing around the waist, tight socks around the ankles, after manual work, after wearing tight shoes, walking, climbing, or carrying heavy backpacks.

Cholinergic Urticaria
Urticaria that appears due to factors such as taking a hot shower, consuming hot drinks, eating spicy food, or experiencing excitement or stress. It generally develops due to an increase in body temperature.

Cold and Heat Contact Urticaria
Cold urticaria and heat urticaria are types of hives that develop after contact with substances of different temperatures. Cold contact urticaria develops after exposure to cold water, ice, or cold air, while heat contact urticaria occurs after contact with hot water, sunlight, or heated objects.

Aquagenic Urticaria
This type of urticaria occurs after contact with water, regardless of its temperature. In addition to water, contact with fluids such as tears and sweat can also trigger aquagenic urticaria.

Exercise-Induced Urticaria
This type of urticaria develops particularly after intense exercise. Symptoms may appear during the exercise or after some time following the exercise.

Vibratory Urticaria
This type of urticaria occurs due to vibration. It can develop after using devices that create vibration, such as mixers and food processors, or from activities like riding a bicycle.

Solar Urticaria
This type of urticaria is triggered by exposure to certain wavelengths of sunlight. It is also known as sun urticaria.

How Does Urticaria Resolve?

The symptoms of hives can be confused with many other skin conditions or diseases that cause skin symptoms. Therefore, before addressing how urticaria resolves, it is essential to confirm that the condition is indeed hives. The most effective way to do this is to consult a doctor and undergo a physical examination. Individuals who experience urticaria occasionally can usually recognize the redness and itching as hives. Chronic urticaria patients can benefit from antihistamine medications, commonly prescribed as allergy medications, by their doctors. It is essential to avoid using medications without a doctor's recommendation. In cases of acute urticaria, if there is contact with any chemicals or allergens, that contact should be avoided. If symptoms do not improve within a few days, it is necessary to consult a doctor. However, if swelling of the tongue or lips (angioedema) or worsening of urticaria occurs, or if symptoms like shortness of breath or confusion appear, immediate medical attention should be sought without waiting for improvement.

Can Urticaria Be Prevented?

If the cause of the urticaria is known, such as an identified allergen, the patient can largely prevent urticaria by avoiding contact with that trigger. In this regard, allergy testing may be helpful for individuals experiencing urticaria. In cases of food allergies leading to hives, avoiding the consumption of the triggering food is necessary. In babies who are breastfed, hives can also be triggered by the foods the mother consumes or the medications she takes. Therefore, mothers should follow their doctor's recommendations and pay attention to their diet. The most effective method of preventing hives is avoiding the allergen; however, this is not possible in cases of idiopathic urticaria (where the cause is unknown). In such cases, using medications prescribed by a doctor after the symptoms are felt can be effective in preventing the worsening of hives.

Which Specialty Controls Urticaria?

Patients experiencing hives symptoms should first visit the dermatology clinics of hospitals. After a physical examination by a dermatologist, it can be determined whether the symptoms are due to urticaria. Additionally, certain blood tests may be required. If rashes persist for more than 24 hours, underlying diseases need to be investigated. Before investigating the allergy and the allergen causing it, the possibility of these underlying conditions should be ruled out.

Urticaria Treatment

There are many treatments for urticaria, but currently, there is no definitive cure. Unlike infections that heal with antibiotics, or diseases like hypertension and diabetes that require continuous treatment, urticaria treatment should continue as long as the condition persists. The first-line treatment usually involves antihistamine medications. Non-sedating antihistamine medications can help resolve most cases of urticaria. If symptoms do not improve within 2–4 weeks, the dosage of medication may be increased under the supervision of a doctor. In cases where symptoms persist despite the maximum dose of non-sedating antihistamine, injectable treatments (injections) under the skin may be used. These injections are administered once a month. Patients receiving treatment should be regularly monitored according to the doctor's recommendations, and their health checks should be ongoing to assess the effectiveness of the treatment. If an allergy to insect stings, medications, or other allergens is identified, the patient should be thoroughly informed, and preventive measures should be taken. A patient with a known medication allergy should always mention it in all consultations and hospital visits. Additionally, because there is a higher risk of anaphylaxis (severe allergic shock) following exposure to the allergen, it is critical to seek medical help immediately without delay.

If you are struggling with urticaria or experiencing symptoms that may suggest hives, you can consult a dermatologist for an examination. By following your doctor's recommendations, you can take necessary precautions to prevent the symptoms and protect your health.