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Experiencing skin changes during pregnancy is normal, but how do you tell if it’s a skin rash or something else? About 1 in 5 pregnant women experience skin changes during pregnancy, such as stretch marks, acne, darker skin, or hives. Hormonal changes during pregnancy can also make your body more sensitive to certain germs and triggers. A trigger is anything that can set off a reaction, like certain foods, medications, stress, or environmental factors.
Hives can start before pregnancy, worsen during it, or appear for the first time while you’re pregnant. If hives last for more than six weeks, you may have chronic hives (also called chronic urticaria).
This article explains what causes chronic hives during pregnancy, how they’re treated, and when to see your doctor.
Hives occur when mast cells release histamine, a chemical that causes your blood vessels to swell and leak fluid into the surrounding skin. Mast cells are found throughout the body, especially in the skin, lungs, and digestive tract. They play a key role in allergic reactions and inflammation by releasing histamine and other chemicals.
The itchy raised bumps caused by histamine release can be large or small, and vary in coloration depending on your skin tone. For some people, hives appear red or pink; for others, they may look brown, purple, or the same color as your skin with a slight swelling.
Chronic hives differ from acute hives because they last longer. Acute hives resolve within six weeks, even though they may come and go during that time. They often occur due to allergic reactions, such as bug bites, certain foods, or medications.
There are two subtypes of chronic hives:
Acute hives during pregnancy or after delivery (called postpartum hives) are less common than other skin changes people may notice during this time, but they can still occur.
Acute hives may be caused by:
Contending with chronic hives during pregnancy can be a bit more challenging since they last longer and can affect quality of life. Some people may have chronic hives before becoming pregnant, and symptoms may improve, stay the same, or get worse.
In a study of 288 pregnant women with chronic hives:
The cause of chronic hives is usually unknown (sometimes called “idiopathic”). However, researchers believe a few factors can play a role in the development of chronic hives during pregnancy.
Higher levels of estrogen during pregnancy can cause mast cells to release more histamine, which can lead to more hives.
Immune response changes can also affect the likelihood of developing hives. In one study, about 43 percent of women with chronic hives reported flare-ups during pregnancy.
Most often, these flare-ups occurred during the first or third semesters. During these stages, there’s a stronger immune response that increases mast cell activation, which can cause hives.
Pregnancy can be stressful, and high stress levels can trigger hive flare-ups or make them worse. Managing stress is an important part of managing chronic hives during pregnancy.
Sometimes, pregnancy-related skin conditions can look like hives but are actually something else.
Pruritic urticarial papules and plaques of pregnancy (PUPPP) are small outbreaks of bumps and patches that can appear on the skin later in pregnancy. These bumps typically appear on the abdomen (stomach) first, but they can spread to the legs and arms, and can be extremely itchy.
PUPPP generally happens during a person’s first pregnancy. While the cause of PUPPP is unknown, some research suggests it might be related to genetics.
PUPPP generally goes away after giving birth. It can be managed during pregnancy with anti-itch cream or medications prescribed by a healthcare provider.
Cholestasis is a liver condition that can cause severe itching, especially during late pregnancy.
In cholestasis, the liver can’t move bile out as efficiently as usual. This causes bile to build up in the liver and bloodstream. Bile is a fluid in the liver that helps break down fats.
When bile builds up, it can lead to intense itching. Cholestasis can increase risks for both the pregnant person and the baby, so healthcare providers usually monitor the pregnancy closely and offer treatment if needed to help prevent complications.
Cholestasis usually occurs because of increased levels of estrogen and progesterone during pregnancy. It usually starts after the 28th week of pregnancy, but it can sometimes happen earlier.
Managing chronic hives during pregnancy can be challenging. Many treatment options aren’t well studied for safety. Health specialists recommend that medications during the first trimester of pregnancy be limited.
Always talk with your OB-GYN and dermatologist (skin specialist) before starting any new drugs.
Antihistamines are a type of medicine that helps stop itching, discoloration, and swelling caused by hives. They block the effects of histamine released by mast cells, so the itching and swelling go away. They are available over the counter and by prescription.
Systemic treatments — medicines that affect the whole body — are generally avoided in the first trimester of pregnancy to reduce risk to the baby.
Second-generation antihistamines are generally safest during pregnancy. They haven’t been linked to birth defects, but you should still discuss options with your healthcare team to weigh benefits and risks. Because first-generation antihistamines cause drowsiness, doctors usually prefer second-generation ones.
Second-generation antihistamines, such as cetirizine and loratadine, are generally considered safe during pregnancy.
First-generation antihistamines like diphenhydramine, hydroxyzine, and ketotifen are generally not advised for use during pregnancy, even though there’s no clear evidence that they cause birth defects.
Among the first-generation options, chlorpheniramine is considered one of the safer choices.
Corticosteroids help reduce inflammation, swelling, and itching from hives, but they’re generally avoided during pregnancy because they can cause complications such as poor fetal growth, large birth size, or stillbirth.
If corticosteroids must be used, they’re recommended only for short-term flare-ups, since prolonged use may raise the risk of side effects including:
In severe cases of urticaria in pregnancy, a very low dose for less than five days may be prescribed, which is unlikely to cause pregnancy complications.
Omalizumab (Xolair) is a medicine that helps control hives that don’t respond to antihistamines. It works by blocking a substance in the body called IgE, which normally triggers allergic reactions. By stopping IgE from attaching to mast cells, omalizumab helps prevent the release of histamine. This reduces the itching and swelling that occurs with hives.
Omalizumab is only recommended during pregnancy when second-generation antihistamines don’t work. It should be used with caution, as one study found a higher rate of preterm births among mothers who took it.
More research needs to be done to understand which drugs are safest during pregnancy in people with chronic hives.
Some people find their hives improve after giving birth, while others continue to have symptoms.
A study in pregnant women with chronic hives found that after giving birth:
In another study, half of the individuals whose hives improved during pregnancy said their symptoms got worse after giving birth, while half who got worse during pregnancy saw no change afterward.
The researchers think this happens because the immune system changes after childbirth. This change can make some kinds of hives worse, while allergy-related hives may get better.
When breastfeeding, it’s important to talk to your doctor about which medications are safest. Guidelines suggest that small amounts of antihistamines are excreted in breast milk. Second-generation antihistamines are recommended since they have fewer sedative side effects on both the mother and the nursing baby.
Higher doses of antihistamines should be used carefully during pregnancy, as limited research is available on their safety for the developing baby.
Hives are often uncomfortable, but they can also be a sign of a severe reaction.
If you have a skin condition, tell your doctor about any changes in your symptoms during pregnancy. Also, review all the medications you use to treat your condition with your doctor to ensure they’re safe to take while pregnant.
Call your doctor right away if you have swelling of the lips, tongue, or throat, trouble breathing, or signs of infection such as fever, pus, or severe pain at the hive sites.
On MyChronicHivesTeam, people share their experiences with chronic hives, get advice, and find support from others who understand.
Have your hives improved or worsened since you became pregnant? Let others know in the comments below.
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