Antihistamines may not work for some people, depending on the severity of their hives. You may need an increased dosage or a different medication altogether.

After a chronic idiopathic urticaria (CIU) diagnosis, your doctor will likely prescribe an oral antihistamine to treat your symptoms. However, antihistamines aren’t always effective.

If you’ve already tried an antihistamine and you aren’t seeing results, schedule an appointment with your doctor to learn about possible next steps.

Here are some questions you can ask your doctor at your follow-up appointment and some information about what you might hear in response.

It’s hard to say why antihistamines work for some people and not for others. But it’s not uncommon for antihistamines to be or become ineffective.

Research on the effectiveness of antihistamines for chronic hives has shown a response rate as low as 43%. It took a secondary treatment with additional medications to bring 28% of the subjects into remission.

Antihistamines may stop working because hives can become worse over time or because the intensity of hives can wax and wane over time.

It’s also possible that antihistamines become less effective because people aren’t taking them as prescribed.

Even if you can’t identify the cause of your CIU, you may be able to pinpoint triggers that bring on outbreaks or increase the severity of your hives.

See whether any of the following common triggers seem to affect you:

  • pets or pet dander
  • exposure to extreme heat or cold
  • exposure to direct sunlight
  • vigorous exercise
  • pressure on the skin
  • stress or anxiety
  • nonsteroidal anti-inflammatory drugs (like ibuprofen)

By understanding your personal triggers, you can put yourself in a better position to avoid them.

After seeing little to no results from an antihistamine, your doctor may suggest that you try the following treatments, usually in the following order:

  • Higher dose: Sometimes increasing the dose of your current antihistamine can yield better results.
  • A different antihistamine or a combination of several different antihistamines. Your doctor may consider switching you to a different antihistamine or putting you on a regimen of two types of antihistamines. For example, they may recommend an H1-antihistamine combined with an H2-antihistamine, which targets different receptors in the body.
  • Oral corticosteroids. While doctors usually don’t recommend prolonged use of steroids due to potential side effects, they may recommend a short course. This is especially likely if your hives are severe or if they’re accompanied by swelling.
  • Cyclosporine (Gengraf, Neoral, Sandimmune): This is an immunosuppressant drug that has led to remission from hives in 50% of cases, according to research.
  • Omalizumab (Xolair). Your doctor may recommend omalizumab, a medication that’s injected once a month if your hives are difficult to treat, but is effective in 80% of cases.
  • Leukotriene receptor antagonists (LTRAs): Two drugs, zafirlukast (Accolate) and montelukast, might be prescribed in cases of hives caused by Aspirin, and there isn’t enough data on their effectiveness on hives overall.

If your medication isn’t giving you the relief you need, you can try the following methods to ease itching:

  • Moisturize regularly with lotion.
  • Use cool water when you shower.
  • Apply a cold compress or an ice pack to affected areas.
  • Try using over-the-counter creams such as calamine lotion.
  • Wear loose clothing made from 100% cotton or 100% silk.

While none of the above methods will treat your CIU, they can at least provide comfort during a flare-up.

Dietary changes to help prevent hives

Researchers are still studying whether changing your diet can impact the severity and duration of CIU flare-ups.

A 2018 preliminary Korean study suggests that an antihistamine diet, where you avoid foods that contain high levels of histamine, may help reduce the severity on an individual level.

Since this and other similar studies only involved a small group of participants, researchers aren’t ready to draw wide conclusions about the diet’s success rate.

Even so, it may be worth talking with your doctor to see whether changing your diet is a good option.

No. Hives are never contagious, so you don’t need to worry about spreading them to friends, family members, or others who are in close contact.

You also don’t have to worry about the hives spreading if you touch other parts of your body after touching your hives.

If you’re concerned about what other people will think when they see the welts on your skin, you can ask your doctor to provide a note explaining the nature of CIU and its symptoms. This can be especially useful for school-aged children.

No. While it may be frustrating to learn that antihistamines aren’t effective at treating your hives, you don’t need to worry that they will leave any permanent marks or scars.

Most hives last for no longer than 24 hours and should fade and disappear after that.

While most cases of CIU aren’t dangerous, there are several warning signs that you should be aware of. Sudden and severe hives can mean you’re experiencing an allergic reaction and need urgent medical attention.

If you experience any of the symptoms of anaphylaxis alongside a hives outbreak, call 911 or go to the emergency room:

Recognizing anaphylaxis

Anaphylaxis is a severe reaction to a trigger, such as an allergy, and is potentially life threatening.

Symptoms can develop quickly and include:

  • feeling faint or lightheaded
  • difficulty breathing or wheezing
  • rapid heartbeat
  • confusion
  • anxiety
  • clammy skin
  • collapsing or losing consciousness
  • hives
  • swelling
  • stomach pain, nausea, or vomiting

If you or someone nearby develops these symptoms, you should:

  1. Check to see whether they have an epinephrine pen. If they do, read and follow the instructions to dispense the medication.
  2. Dial 911 (or a local emergency number).
  3. Lay them down. If they have vomited, lay them on their side.
  4. Stay with them until emergency services arrive.

It is possible for someone to need more than one injection with an epinephrine pen. If symptoms do not begin to clear after 5 minutes, give a second injection if one is available.

Was this helpful?

By definition, “chronic” means that your hives will last for 6 weeks or more. But there’s no way to say for sure exactly how long a specific outbreak episode will last. It could be months or even years.

Each individual welt will probably last for several hours, but they’re often quickly replaced by new ones.

The good news is that CIU can go away, it’s just hard to predict when.

Should I see an allergist?

If you’ve already been diagnosed with CIU, your doctor believes the cause is unknown and an allergy isn’t to blame. But if you suspect that your doctor overlooked an underlying allergy, you may want to consider seeing an allergist.

What happens if hives don’t go away with Benadryl?

Benadryl (diphenhydramine) is an over-the-counter antihistamine that can be used to treat mild allergic reactions, including hives. It is an H1 antihistamine, which means it is one of the ones your doctor may want you to try first. It is also available in higher doses as a prescription if the OTC version doesn’t work for you. If it’s still ineffective, your doctor will likely switch you to H2 antihistamines, other medications, or a combination of drugs.

Why is Benadryl not stopping my allergic reaction?

If there is an ongoing trigger for your hives in your environment, you might continue to develop them or they may worsen even if you’re taking an antihistamine like Benadryl. In addition to taking medication, it’s important to try to identify the trigger and eliminate it. To do this, make an appointment with a dermatologist or allergist for testing, and track your flare-ups. That said, sometimes there is no identifiable cause. Make sure you are taking your medication exactly as prescribed or following the directions on the box of any OTC drug.

If antihistamines don’t work for you, don’t become discouraged. This happens for certain people and under certain circumstances.

Ask your doctor about possible next steps. Whether that involves a different form of medication or introducing some natural steps to reduce itching, you have options to decrease CIU-related discomfort.