Hives is a red, swollen, itchy skin rash that is rarely caused by an allergen. An allergen is a result of an allergic reaction.
It is also called urticaria, welts, weals, or nettle rash.
When there is an allergic reaction the body produces a protein called histamine. The tiny blood vessels known as capillaries leak fluid, when histamine is released. The fluid builds up in the skin and causes a rash.
At some time in their lives, hives affect about 20 percent of people.
It is not contagious.
Causes
Urticaria develops when the body responds to an allergen, releasing histamine and other chemicals from below the skin surface.
The histamine and chemicals cause the accumulation of inflammation and fluid under the skin, producing wheals.
Established causes Examples include:
- medications, including some antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ACE inhibitors, used for high blood pressure
- foods, such nuts, shellfish, food additives, eggs, strawberries, and wheat products
- infections, including influenza, the common cold, glandular fever, and hepatitis B
- bacterial infections, including urinary tract infections and strep throat
- intestinal parasites
- extreme temperatures or changes in temperature
- high body temperature
- pet dander from dogs, cats, horses, and so on
- dust mites
- cockroaches and cockroach waste
- latex
- pollen
- some plants, including nettles, poison ivy, and poison oak
- insect bites and stings
- some chemicals
- chronic illness, such as thyroid disease or lupus
- sunlight exposure
- water on the skin
- scratching
- exercise
People never discovers the exact cause in more than half of all cases.
Chronic hives may start as an autoimmune reaction but it’s uncertain why it happens.
Treatment
Non-sedating antihistamines taken daily for several weeks are used in the treatment for acute urticaria.
Antihistamines, such as cetirizine or fexofenadine, help block histamine symptoms and reduce rash and avoid itching.
Some antihistamines cause drowsiness, particularly when the consumer consumes alcohol, too. Some are unacceptable during pregnancy, unless a doctor prescribes.
Angioedema patients may need to see an allergist, an immunologist or a dermatologist. Angioedema can potentially cause severe breathing problems.
If tongue or lip swelling, or breathing becomes difficult, the doctor can prescribe an epinephrine auto-injector, such as EpiPen, in the event of an emergency.
Patients can, if possible, avoid identified causes.
Chronic urticaria
Chronic hives can give rise to long-term pain, and complications can also occur.
Treatment for acute urticaria is special to that.
For example, Dapsone antibiotics can reduce redness and swelling.
Omalizumab, or Xolair, is an injectable drug which blocks immunoglobin E, a substance which plays a role in allergic reactions. It may decrease symptoms of chronic idiopathic urticaria, a form of unknown cause hives that may last for months or years.
Those suffering from serious symptoms may need to see a specialist.
Acupuncture can help treat hives, however a systematic review published in 2016 concluded that “Acupuncture may be successful and secure in relieving symptoms of chronic urticaria on the basis of a low level of evidence.” The authors called for more research to validate findings.
Chronic hives can lead to extreme pain, discomfort and likely depression. Stress can exacerbate the hives too, creating a vicious cycle. Patients who have depressive symptoms should speak to a doctor.
Symptoms
Swellings, known as wheals, turn up on the skin as a rash. They appear to be pink or red, with an oval or round shape. They can range from several millimeters through to several inches. These can be quite itchy, and have a red flare around them.
Typically the wheals occur in abundance, mostly on the face or extremities, like the arms, hands, fingers, legs, feet, and toes.
Welts usually go away within 24 hours, but new ones could be forming. They can appear on only one part of the body, or multiple sections.
Symptoms usually go away within 24 hours, but often another weal begins to fade like the last one.
Hives will in some cases continue for several days. People with chronic hives can suffer for months or years from symptoms.
Anaphylaxis
Anaphylaxis is a serious allergic reaction with the ability to affect the whole body.
It may cause serious breathing problems and a loss of consciousness. If it is not treated rapidly it can be fatal. It’s a health emergency.
Immediate medical attention is needed if there is:
- nausea and vomiting
- swelling of the lining of the mouth, tongue, lips, and throat, causing breathing difficulty
- cold and clammy skin
- rapid heartbeat
- faintness or lightheadedness
- an unexpectedly abrupt feeling of intense anxiety
People with hives need to be alert to any new signs that could suggest an anaphylactic reaction.
Home remedies
Triggers may not cause the problem but can aggravate symptoms, so patients should seek to recognise them and stop them.
This may include:
- abstaining from or cutting down on alcohol
- avoiding certain medications
- avoiding stress, if possible, perhaps with meditation or relaxation techniques
- choosing some soaps, skin creams, and detergents that are mild.
Avoiding certain foods may be beneficial. Spinach, fish, yogurt, meat, tomato, processed meats, chocolate, and strawberries are known to cause histamine development.
Tips to reduce the irritation caused by hives include:
- wearing loose, light clothing
- avoiding scratching
- use soaps for sensitive skin
- use a shower, fan, cold water, lotion, or cool compresses to cool the area
- take an oatmeal bath with tepid water
- avoid known triggers
Some reports recommend supplements such as quercetin and primrose oil during night, and vitamin C, D and others. Before using supplements, it is important to speak to a doctor because these can cause adverse reactions.
Keeping a flareup record can help to identify a cause.
Hives and stress
Emotional stress is one cause of hives, or a factor which may make symptoms worse.
A 2005 study in 75 participants linked stressful life events, low family support, insomnia and hives.
Many scientists have clarified how “chronic stress can contribute to mediator dysregulation and intensify the underlying pathophysiology of inflammatory disease.”
In other words, if a person is stressed, any inflammatory reactions in a person susceptible to a reaction are likely to be more serious. Hives, or urticaria, may be related to stress in this way.
Types
Hives, or urticaria, can be acute or chronic.
Acute urticaria is the most common type. Symptoms last less than 6 weeks, and they typically affect the face and neck, fingers, toes, and the genitals of males. However, any part of the body can be affected.
Chronic hives: continues for more than 6 weeks. It is estimated that around 1 in every 1,000 people experiences chronic urticaria.
The exact cause is unclear but may be linked to the immune system. Viruses can cause hives, too. For certain cases, this can lead to an underlying autoimmune condition, such as thyroid or lupus disease.
Angioedema: can happen, too. This is similar to hives, except it affects the skin’s deeper layers.
Diagnosis
Diagnosis will depend on the type of urticaria.
Acute urticaria
A health care professional may diagnose acute hives by observing the skin rash.
Identifying the cause will help avoid recurrences in the patient.
Probably, the doctor will inquire about:
- when and where the episode began
- whether there has been an insect bite
- whether the patient lives or works in a place where potential triggers may exist, such as latex gloves, chemicals, or animals
- any medications the patient has been taking, including herbal supplements
- the patient’s medical history
- any family history of urticaria
The trigger is sometimes unclear but the doctor can refer the patient to an allergy clinic if there appears to be a specific trigger.
Allergy clinics check the blood and skin of the patient to decide whether there is an allergy to certain things, such as chemicals, dust mites or some food.
Chronic urticaria
If the hives continue for more than 6 weeks, the cause is possibly not natural, but at this stage experts are not suggesting allergy tests.
The following tests could investigate underlying health conditions:
- blood test to check for anemia
- stool sample to identify any parasites
- erythrocyte sedimentation rate (ESR) test, to identify problems with the immune system
- thyroid function test to assess for an overactive thyroid, known as hyperthyroidism, or hypothyroidism, an underactive thyroid
- liver function tests, in case there are liver problems
Factors that may worsen the existing urticaria include:
- alcohol
- caffeine intake
- mental health issues, such as stress
