Urticaria or hives: overview, symptoms, causes, diagnosis and management

Urticaria is the medical term used for hives. Hives are a type of skin rash that are red, itchy and bumpy. They occur in reaction to some triggers which can include chemical, drugs, irritants or anything. They appear suddenly and usually disappears quickly.

Urticaria is a very common condition. About 20 percent of individuals experience hives at some point of their lifetime.

Symptoms

Signs and symptoms of hives appear suddenly and disappears within hours and consists of

Skin rashes: in appearance they are red or skin colored, swollen bumps with clear edges. They can resemble bug bites but they differ from bug bites as

• Duration: they appear suddenly and lasts for hours depending upon the types of hives
• Site: it can appear anywhere on the skin and body including face, tongue, lips, ears or even throat.
• Size: the size of hives varies widely. It can range from the size of a pencil eraser to the size of a food plate. Their shapes can change as smaller rashes join to form bigger plaque like lesions.
• Itching: most of the hives are associated with itching which may range from mild to severe.
• Blanching: the center of a red hive turns to white when pressed.

Angioedema is the condition different from hives which can be seen in almost half of the patients of hives. It is characterized by swelling which is beneath the skin instead of surface like swelling around the eyes, lips or whole of the face. A sensation of fullness or discomfort in those area is felt. It usually last longer than hives. Angioedema of throat, tongue or lungs can be life threatening condition as it disrupts normal breathing.

Causes

Hives occur in response to triggers that activates the immune system cells of the skin. These cells known as mast cells upon activation releases a chemical histamine which is responsible for all the signs and symptoms

These triggers can be allergic reactions, medications, sunlight exposure, insect stings or any offending agents. Many a times it is difficult to find out the trigger.

There are three different types of hives based on for how long one is suffering from the hives

• Acute or brief: the hives don’t last less than 6 weeks while the duration of each episode is much lesser. Most cases of hives are acute and lasts for a few days or a week. Triggers for acute hives include viral infections, drugs such as aspirin, ibuprofen or naproxen, insect stings, food allergies or physical contact with substances to which a person is allergic.
• Chronic hives: the episodes occur for the duration longer than six weeks. Hives occur almost daily and can interfere with daily life such as sleep, work or school. They are rarely permanent as it is seen that about 50 % of people get rid of them within a year. The cause is not known in most of the cases while in some the cause is suspected to be underlying thyroid disease, hepatitis or cancer.
• Inducible hives: these are the hives which are induced by some physical factors and these physical factors include exposure to cold, changes in body temperature, sweating, vibration, pressure, exercise, sunlight or water. There is a form of physical urticaria in which hives are formed when the skin is firmly stroked.

Diagnosis

The diagnosis of hives is usually based in their symptoms and a physical examination. It is important to separate symptoms of angioedema from hives. Testing is not required in the most of the cases but may be recommended in people whose hives don’t resolve within six weeks.

Medical history: your doctor will ask you various questions about your symptoms, any associated food intake, any allergies, family history or any drug or chemical exposure. To identify the trigger, active participation of both the physician and the patient is required. Depending upon the history your doctor may recommend some tests.

Testing: Skin testing can be performed if food or drug allergies are expected. It is usually performed in people who are suffering from acute hives as chronic hives are rarely caused by allergies. Blood test can be recommended in individuals if systemic diseases are suspected or specific allergen is to be tested.

Skin biopsy: A skin biopsy where small sample of skin is taken for further testing may be recommended in those where an uncommon cause is suspected. This is done in people who are suffering from chronic hives along with the other symptoms.

Management

A combination of methods can be used to manage hives that include prevention and treatment as

Avoiding triggers: The best management option for hives is to prevent it from occurring. It can be done by identifying triggers and avoiding them.

Medications

Antihistamines: these are the medications used to relieve the symptoms caused by histamine. They can prevent the symptoms from occurring if taken prior. There are two type of antihistamines which differ in their side effect profile and efficacy. These are older and newer antihistamines. These are available as over the counter drugs. A physician can recommend the most suitable antihistamine for you.

Oral steroids: they are used when even the high doses of antihistamines are not able to control the symptoms. They cannot be used for long terms due to their side effects. Once the symptoms are relieved the steroid dose is gradually lowered and then stopped.

Other medications are also available which is given by specialist depending upon the patient condition and  these specialists are either dermatologist or allergist.

References

• American Academy of Dermatology
• Kaplan AP. Urticaria and angioedema. In: Middleton’s Allergy: Principles and practice, 7th, Adkinson NF, Bochner BS, Busse WW, Holgate ST, Lemanske RF, Simons FER (Eds), Mosby, St Louis, MO 2009. Vol 2, p.1063
• Sackesen C, Sekerel BE, Orhan F, et al. The etiology of different forms of urticaria in childhood. Pediatr Dermatol 2004; 21:102.
• Kaplan AP. Clinical practice. Chronic urticaria and angioedema. N Engl J Med 2002; 346:175.
• Kaplan AP. Chronic urticaria: pathogenesis and treatment. J Allergy Clin Immunol 2004; 114:465.