Hives look like raised bumps or welts. They may be the same color as the surrounding skin or have a reddish hue, though this may not appear on black skin.
An allergic skin reaction causes hives, known medically as urticaria.
While hives can be itchy and uncomfortable, various home remedies and treatments can provide relief and resolve the issue.
Hives can appear as swollen or raised bumps, which may be isolated or spread over a larger area of skin. The swelling can stretch the hair follicles in the area, causing them to appear more prominent.
Hives can also cause redness, which may be more subtle or not appear on black skin.
Hives often develop when the skin comes into contact with an irritant. In this case, a doctor may call it “contact urticaria.”
There are three subtypes of contact urticaria:
- immunologic contact hives
- nonimmunologic contact hives
- contact hives due to an unknown mechanism
We describe them in detail below:
Immunologic contact hives
This reaction can be dangerous, and it can cause hives to spread across large areas of skin. It may stem from one of four types of triggers:
- plant proteins — from vegetables, fruits, or spices, for example
- animal proteins — such as in meat, dairy, or seafood
- grains — such as wheat, barley, or rye
- enzymes — such as alpha-amylase in starch, cellulase in coffee, and xylanase in whole wheat and grains
Immunologic contact hives develop when chemicals in the body, including histamine, are released in response to a trigger. Continuous exposure to the trigger can cause the reaction to worsen.
A person may experience it in stages:
- swelling at the point of contact with the trigger, leading to burning and itching and possibly redness
- hives that spread from the initial point of contact
- symptoms of asthma, conjunctivitis, difficulty swallowing, and nausea
- anaphylactic shock
Anaphylactic shock is potentially life threatening. It occurs when the body’s immune symptom overreacts to an allergen and blood pressure drops dangerously low.
Common symptoms of anaphylactic shock include:
- nose, mouth, skin, or stomach irritation, such as hives, diarrhea, or congestion
- breathing difficulties, such as wheezing
- fainting, dizziness, or confusion
- a sense of doom
- swelling of the mouth, tongue, throat, or lips
- color changes to the mouth or lips, which may appear whitish or grayish in black skin
- a choking sensation or trouble swallowing
Anyone who may be experiencing this should receive emergency medical care. A person may need to use an adrenaline or epinephrine auto-injector, such as an EpiPen, while waiting for help to arrive.
Nonimmunologic contact hives
This issue is more common and less severe, and the hives tend to only form at the site of contact with a trigger.
Some triggers for this type of hives include:
- animals, including caterpillars
- food, spices, and herbs, such as pepper and thyme
- fragrances and flavorings
- medication, such as witch hazel
- metals, such as cobalt
- plants, such as nettles
- preservatives and disinfectants
Contact hives due to unknown mechanisms
Sometimes, a doctor cannot tell whether hives result from an immunologic or nonimmunologic reaction.
For example, ammonium persulfate, which can be found in certain types of rubber, can trigger hives that respond to immunologic and nonimmunologic treatments.
The best approach depends on whether the hives are acute, in which case they are an isolated or short-term issue, or chronic, in which case they are long-lasting.
A doctor is likely to recommend an antihistamine, such as cetirizine (Zyrtec), for acute hives.
If the issue is severe, the doctor may recommend taking 2–4 times the regular dose. If this is ineffective, the doctor may recommend an additional antihistamine, such as cimetidine (Tagamet).
When the hives are severe, doctors may also prescribe a 3–10-day course of corticosteroids.
If a person is at risk of anaphylactic shock, a doctor will likely prescribe an epinephrine auto-injector, sometimes called an EpiPen. They may ask to see the person again within 6 weeks of the prescription, to ensure that there have been no adverse side effects.
When a person has chronic hives, the doctor will likely follow a four-step treatment plan.
The first step is prescribing a daily antihistamine. If this is ineffective, the doctor recommends taking 2–4 times the regular dosage.
They may also recommend another antihistamine or another type of medication, such as montelukast (Singulair). In addition, they may advise the person to take an antihistamine, such as diphenhydramine (Benadryl), before bed.
If the person is still experiencing the hives, the doctor may prescribe a stronger antihistamine, such as hydroxyzine (Atarax). If this is ineffective, the doctor may refer the person to a specialist, who may prescribe cyclosporine or omalizumab (Xolair).
If the hives become manageable at any stage, the doctor may begin reducing the amount of medication that the person takes.
If a person has an occasional flare-up of chronic hives while taking the medication, the doctor may prescribe an additional 3–10-day course of corticosteroids.
To prevent hives, a person can try to avoid:
- any triggers of hives
- aspirin, alcohol, and nonsteroidal anti-inflammatory drugs, or NSAIDs, such as ibuprofen (Advil)
- tight clothing
A person who has hives may find relief from using oatmeal-based products, which may relieve itchy skin irritation. It is important to check every product’s ingredient list for allergens, however.
Having a cool shower or placing a cool compress on the affected area may also help soothe the skin.
The American Academy of Dermatology recommend trying anti-itch medication, such as calamine lotion, and using fragrance-free moisturizer several times a day on dry skin, to prevent irritation.
Anyone who notices hives after coming into contact with a particular trigger, they should make an appointment with a doctor to discuss the best approach.
It is important to see a doctor about any possible allergies, as repeated exposure can lead to anaphylactic shock. This requires emergency medical care.
Acute hives tend to go away if people avoid triggers.
Research indicates that 35% of people with chronic hives are symptom-free within 1 year and that 68% of children have “outgrown” reactions to triggers within 5 years.
Hives tend to simply be uncomfortable, but they can be severe, and they may lead to anaphylactic shock, which can be life threatening.
If home remedies do not work, contact a doctor. Anyone who believes that they may have an allergy should also let a healthcare provider know.