Definition

Urticaria, commonly called hives, is a skin disorder distinguished by itchiness and the manifestation of red, distinct rashes. These rashes typically exhibit a swollen and thickened appearance. The term "urticaria" originates from the European insect Urtica dioica, as the skin rash associated with urticaria resembles the reaction caused by being bitten by this insect.

Urticaria is usually triggered by various factors, including air temperature, humidity, dust, certain foods, animal fur, and specific medications. The condition can be classified into two types based on its duration:

• Acute urticaria: This form typically resolves within a few hours to under six weeks.
• Chronic urticaria: Characterized by intermittent episodes, chronic urticaria can persist for longer than six weeks.

Most people have likely encountered urticaria skin rashes at least twice in their lifetime. However, urticaria is not an infectious disease that can spread between humans.

However, if you do experience urticaria, it's crucial to be aware of the potential for anaphylactic shock, a severe allergic reaction that can be life-threatening. Seek immediate medical assistance if you experience any of the following symptoms:

• Swelling in the face, lips, tongue, or throat.
• Increased heart rate.
• Dizziness.
• Shortness of breath.
• Skin rash appears all over the body.

Causes

Urticaria can occur due to excessive histamine release in the skin layer. Histamine is a substance involved in the body's immune response to certain triggers. It can cause blood vessels in the skin to dilate, which often results in skin reactions like swelling and redness. However, it's important to note that no clear underlying cause is identified in many cases of urticaria.

Allergens

Allergens, substances capable of triggering allergic reactions in the body, prompt the release of histamine, a protein, during an allergic response. The immune system identifies allergens as foreign and potentially harmful agents in some individuals.

Examples of allergens that may provoke the onset of urticaria include:

• Certain medications, such as antibiotics, nonsteroidal anti-inflammatory drugs (e.g., aspirin), and certain antihypertensive drugs.
• Foods like nuts, eggs, seafood, and specific fruits such as kiwi, bananas, and mangoes.
• Latex.
• Certain plants.
• Preservatives present in food, cosmetics, and various products.

Environmental factors

Environmental factors also play a role in triggering urticaria in susceptible individuals, including:

• Prolonged exposure to sunlight or ultraviolet rays.
• Pressure exerted on the skin, such as from tight clothing or belts.
• High temperatures, leading to sweating or bathing in excessively hot water.
• Physical activities such as exercise.
• Psychological stress or anxiety.
• Habitual scratching or scraping of the skin.

Medical condition

Additionally, several medical conditions can lead to urticaria, including:

• Infections like the flu, common cold, urinary tract infections, and sore throat.
• Bites from insects or animals.
• Other conditions characterized by inflammation of blood vessels.
• Autoimmune diseases, where the immune system mistakenly attacks healthy cells, including:
• Rheumatoid arthritis, which involves joint inflammation.
• Lupus.
• Type 1 diabetes, resulting from insufficient insulin production.
• Autoimmune hypothyroidism, wherein the thyroid gland fails to produce adequate hormones.

Risk factor

Factors that can increase the risk of developing urticaria include:

• Family history: Having a relative with a history of urticaria can increase susceptibility.
• Age: Children are more vulnerable due to their underdeveloped immune systems, while women aged 30-60 years may be at higher risk.
• Occupational exposure: Certain professions with frequent exposure to latex may heighten the likelihood of developing urticaria.
• Medications: Some medications can trigger urticaria as a side effect.
• Psychological stress: Stressful situations can exacerbate or precipitate urticaria episodes.
• Geographic location: Living in regions with distinct seasons may impact urticaria prevalence.
• Autoimmune history: Individuals with a history of autoimmune diseases may have an increased risk of developing urticaria.

Symptoms

Symptoms associated with urticaria may include:

• Skin rashes can manifest anywhere on the body and tend to cluster together.
• The rashes may appear red, pink, or match the skin tone. When pressure is applied to the center of the rash, it often becomes pale.
• Itching is a common sensation experienced with urticaria.
• The size of the rashes can range from small to large, often appearing swollen.

The onset of skin rashes in urticaria can vary depending on the underlying cause. Rashes may develop rapidly, typically within 10-60 minutes after exposure to specific triggers, or they may manifest later. Urticaria commonly affects the feet, arms, back, and face.

For instance, in the case of latex exposure, urticaria may emerge 10 to 60 minutes following contact with the allergen and can persist for up to 24 hours.

Diagnosis

Skin diseases are often closely linked to patients' complaints, medical history, and daily habits. When evaluating a skin condition, doctors may inquire about the following:

• Symptoms: Describe the symptoms you are experiencing, such as itching, redness, swelling, or pain.
• Onset and Changes: Before seeking medical advice, provide details about when the skin rash first appeared and any changes observed in the rash.
• Past Incidents: Mention if you have experienced similar symptoms and how they were managed.
• Recent Activities: Discuss any activities you engaged in within 24 hours before the onset of symptoms, as certain activities or exposures may trigger skin reactions.
• Possible Allergens: Consider any potential exposure to substances that cause allergic reactions, such as certain foods, medications, plants, or environmental factors.
• Medical History: Provide information about your personal and family medical history
• Allergies: Specify any known allergies you have
• Current Medications: Inform the doctor about any medications you are currently taking, including prescription medications, over-the-counter drugs, supplements, or topical treatments.

After gathering information about your symptoms and medical history, the doctor will conduct a thorough examination to assess the severity of your condition and determine if immediate treatment is necessary for a severe allergic reaction. This examination involves inspecting and palpating the skin, observing its color and texture, and assessing the intensity of itching.

During the examination, the doctor will also evaluate the skin rashes to rule out the possibility of other underlying diseases.

Usually, diagnostic tests are not required to diagnose urticaria unless the doctor observes signs and symptoms suggesting another condition or if further evaluation is necessary. However, if additional testing is warranted, the following diagnostic tests may be performed:

• Skin prick test
• Complete blood count (CBC)
• Blood chemistry
• Liver function tests
• Biopsy or skin tissue sampling

Management

The primary approach to treating urticaria involves avoiding exposure to known trigger substances that provoke skin reactions. Doctors often prescribe antihistamine medications to alleviate itching and reduce skin inflammation.

If urticaria is secondary to underlying medical conditions, treatment will focus on addressing those conditions. Medications suspected of causing allergic reactions may be discontinued and replaced with alternative options whenever possible. In severe allergic reactions, healthcare providers may administer adrenaline medication to stabilize the patient's condition.

In addition to medical treatments, patients with urticaria may receive lifestyle recommendations to manage their condition effectively. They are often advised to avoid hot water, avoid scratching the skin, and wear loose-fitting, non-allergenic clothing. 

Complications

Skin rashes associated with urticaria may coincide with a condition known as angioedema, characterized by swelling in the deeper layers of the skin. Furthermore, urticaria can persist over an extended period, leading to recurrent outbreaks that significantly impact the individual's quality of life.

Complications of urticaria may extend beyond physical symptoms, as persistent itching can trigger emotional and physical disturbances. Moreover, urticaria has the potential to progress into severe allergic reactions, posing life-threatening risks that necessitate immediate medical intervention.

It's crucial to seek medical assistance if you experience skin rashes and swelling in areas such as the eyes, tongue, or throat. These symptoms may indicate a severe allergic reaction requiring prompt evaluation and treatment to ensure your safety and well-being.

Prevention

The simplest and most effective strategy to prevent urticaria is by avoiding exposure to substances known to trigger it, as previously discussed. 

When to see a doctor?

Seek urgent medical attention if you encounter persistent skin rashes or if your skin rashes are accompanied by any of the following symptoms:

• Headaches
• Nausea
• Vomiting
• Difficulty breathing
• Swelling of the eyes, lips, tongue, or throat

These signs may indicate anaphylaxis, a severe and potentially life-threatening allergic reaction. Immediate treatment in an emergency room is essential to address this emergency condition and prevent further complications.

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