When you have watery eyes, a runny nose, and itchy skin in the springtime, you probably turn to allergy medications for help. A popular option is antihistamines. These drugs block the chemicals causing your allergy symptoms. Since they can help relieve skin itching, you might wonder if antihistamines can provide quick relief from the uncomfortable itch of psoriasis.

Many MyPsoriasisTeam members have shared their experiences when taking antihistamines. One wrote, “I have psoriasis on my legs, chest, and neck. I’m so itchy. I’m taking antihistamines and using a cream for my skin. I hope it goes away soon.”

This article covers what antihistamines are, how they work, and why they might help if you’re living with psoriasis. Before starting any new medication, be sure to talk with your doctor or dermatologist to make sure it’s safe for you.

What Are Antihistamines?

Your immune system protects you from foreign invaders to stop you from getting sick. While it means well, your immune system occasionally overreacts to harmless substances like pollen, dust, and pet dander. These substances are known as allergens because they set off allergy symptoms.

When your body comes in contact with an allergen, specialized immune cells begin releasing the chemical histamine. Your body has a few types of histamine receptors. For allergy symptoms like itchy skin, H1 receptors are the most important. They’re found in your blood vessels, neurons, and the smooth muscle cells that line your airways.

When your body releases histamine during an allergic reaction, it activates your H1 receptors. Your blood vessels expand to let more blood flow through, which leads to allergy symptoms like itchy skin, watery eyes, and runny nose.

Luckily, there are antihistamines designed to block the effects of histamine. Many prescription and over-the-counter (OTC) antihistamines work by blocking H1 receptors. Also known as H1 blockers, these medications relieve allergy symptoms by stopping histamine from attaching to the receptors.

Types of H1 Blockers

H1 blockers were first approved by the U.S. Food and Drug Administration (FDA) in the 1930s. The drugs are known as first-generation antihistamines, and some are still in use.

One common example you’ve likely taken at some point is diphenhydramine (Benadryl). Doctors also prescribe another first-generation H1 blocker, hydroxyzine (Vistaril), to help treat anxiety and sleep problems. That’s because these H1 blockers can pass through the blood-brain barrier and make you drowsy. Other side effects of first-generation H1 blockers include dry eyes, dry mouth, low blood pressure, and dizziness.

To prevent people from getting sleepy while taking antihistamines, researchers developed a second generation of medications. When you think of an OTC allergy medication, you likely think of a second-generation H1 blocker. Examples you can find in your local drugstore or pharmacy include:

• Cetirizine (Zyrtec)
• Loratadine (Claritin)
• Fexofenadine (Allegra)
• Desloratadine (Clarinex)

While second-generation H1 blockers are nondrowsy, they can cause headaches, abdominal pain, sore throat, and cough.

Can You Take Antihistamines To Treat Psoriasis?

If you’ve looked online to see if you can take an antihistamine to treat psoriasis, you probably didn’t find much information. Antihistamines usually aren’t prescribed for psoriasis, and they may not help much. Studies have found that histamine likely isn’t responsible for causing skin itching in psoriasis.

In a 2023 study of 27 people with scalp psoriasis, the results showed that histamine doesn’t seem to cause psoriatic itch. The University of Miami researchers believe that changes to the sensory nerves in the scalp are to blame. This means that antihistamines likely won’t help treat scalp psoriasis.

Other studies have reported mixed results regarding antihistamines for treating psoriasis. One study from Italy followed 90 people with moderate to severe psoriasis. The researchers found that moisturizers helped 24 percent of people treat their skin itching. On the other hand, antihistamines helped only 13 percent of people for a few days.

However, researchers from Poland followed 61 people with plaque psoriasis who took an antihistamine or placebo (sham treatment). The people in the antihistamine group experienced significantly less skin itching compared with those in the placebo group.

Even though antihistamines might provide some relief, doctors and researchers have found that these drugs aren’t as effective for psoriasis as they are for allergies.

Antihistamines for Nighttime Itching With Psoriasis

If you’re experiencing itching while living with psoriasis, you’re not alone. Researchers estimate that for 70 percent to 90 percent of people with psoriasis, skin itchiness is a problem. Bothersome psoriasis symptoms can also affect your sleep. In fact, studies show that sleep disturbances affect over 85 percent of those with psoriasis.

If itchy skin makes it hard to sleep, you can ask your doctor about using an antihistamine at night. Taking an antihistamine that can cause sleepiness, like hydroxyzine, may make you less likely to wake up in the middle of the night to scratch.

Some MyPsoriasisTeam members have had success with this approach. One member wrote, “I find that the itching is one of the worst things about psoriasis sometimes. The only thing that ever worked for me was antihistamines. I tend to take them in the evening — my itching is always worse at night.”

Another member said they do the same: “I tend to take an antihistamine in the evening. It helps me sleep.”

What Are the Risks and Side Effects of Antihistamines?

Before starting an antihistamine or other new treatment, it’s important to talk with your doctor or pharmacist. They can help you determine the right medication and dosage for treating your symptoms. It’s also important to make sure an antihistamine won’t interfere with other medications you’re currently taking.

All medications, including OTC products, come with their own set of side effects. The most common side effects of antihistamines include:

• Dry mouth and eyes
• Headache
• Dizziness
• Drowsiness
• Cough
• Sore throat
• Nausea
• Vomiting

Many people with psoriasis use other medications to manage their day-to-day symptoms. Common treatment options to help control skin inflammation include topical steroid creams or lotions, immunosuppressants, and biologics. According to Mayo Clinic, antihistamines can interfere with some psoriasis treatments, including methotrexate.

Also, people taking medications for high blood pressure need to be careful with antihistamines, according to Cleveland Clinic. Taking both at the same time may raise your blood pressure and heart rate. If you’re currently on a blood pressure medication and want to try an antihistamine, check with your doctor first.

Talk With Others Who Understand

MyPsoriasisTeam is the social network for people with psoriasis and their loved ones. On MyPsoriasisTeam, more than 126,000 members come together to ask questions, give advice, and share their stories with others who understand life with psoriasis.

Have you taken antihistamines to treat your psoriasis? Did they help address your symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.