Various factors can contribute to an eczema flare-up, including allergens, stress, and cold weather. Identifying potential triggers can help people avoid or manage symptoms.

People with certain types of eczema, such as irritant contact dermatitis, may find that they develop eczema immediately after touching an irritating substance, making identification easier.

However, for people with other forms of eczema, finding the cause of a flare-up may be more difficult.

This article discusses 15 of the most common causes of eczema flare-ups and how a person can reduce their exposure to them.

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Eczema is an inflammatory skin condition that causes patches of itchy, dry skin. Doctors are not sure what the underlying cause for eczema is, but people can often identify one or more triggers for eczema flare-ups.

For example:

  • irritant contact dermatitis is typically the result of direct contact with an irritating substance
  • allergic contact dermatitis flares up due to direct contact with an allergen
  • seborrheic dermatitis may result from a proliferation of certain types of yeast on the skin

However, in some cases, there may be no identifiable cause.

Learn about the different kinds of eczema.

Some people experience eczema flare-ups in response to certain irritants. Common irritants that may trigger a rash include:

  • friction
  • cleanings products, such as detergents or biological washing powder
  • acids, such as lemon juice or vinegar
  • alkalis, such as oven cleaners or baking soda
  • artificial fragrances, such as those in bath products, cosmetics, or cleaning products

Irritants can damage the skin barrier by removing oils and moisture. If the damage continues before the skin has time to repair, this can result in irritant contact dermatitis.

What to do

After identifying the irritants causing the rash, people can avoid them. Other strategies include:

  • rinsing the skin immediately after coming into contact with an irritant
  • patting dry and applying a barrier cream or emollient
  • preventing contact with irritants by wearing protective clothing, such as gloves

Learn more about triggers for contact dermatitis.

Frequent exposure to water can also dry the skin and make eczema more likely. This is particularly true for people who regularly wash their hands.

While a good practice for preventing the spread of viruses, frequent hand washing can worsen hand eczema. This includes washing with:

  • soaps
  • hot water
  • alcohol hand sanitizer

Frequent showering, bathing, or swimming can also remove moisture from the skin.

What to do

People can reduce the impact of necessary water exposure by:

  • using gentle, fragrance-free soaps suitable for sensitive skin
  • using warm water, not hot
  • moisturizing right after any contact with water
  • using washable or disposable gloves to keep the hands clean, reducing the need for hand washing

Learn about hand washing for people with skin conditions.

A 2020 prospective study looked at what triggers cause itching in people with atopic dermatitis. The study found that stress was the most significant trigger in 35.4% of participants.

Stress raises inflammation in the body, which may explain why it can worsen eczema. It is also a risk factor for mental health conditions, including depression and anxiety.

Learn more about the link between stress and eczema

What to do

Just as a person can identify triggers for eczema, they can also identify triggers for stress. It may help to avoid some triggers. If this is not possible, there may be ways to reduce the effects by:

  • reducing the number of tasks a person needs to do each day
  • making time each day for rest and relaxation, even if this is only brief
  • doing stress-relieving hobbies, such as walking, reading a book, or listening to relaxing music

If a person often finds they have difficulty with persistent worry or intrusive thoughts, they may benefit from speaking with a mental health professional.

Learn more about how to reduce stress naturally.

According to the 2020 prospective study, temperature and a lack of humidity in the air can trigger itchiness for those with atopic dermatitis. Around 24% of respondents reported that weather change, dry air, and heat could cause symptoms.

People with eczema may find symptoms are worse in specific climates, seasons, or during seasonal changes. When the weather gets colder, heating systems may dry out indoor air, for example.

The American Academy of Dermatologists (AAD) notes that dry air, heat, humidity, and sudden changes in temperature could trigger symptoms.

What to do

While a person cannot always avoid the climates and seasonal shifts that trigger their eczema, there are ways they can reduce their impact on the skin, such as:

  • keeping the home a comfortable temperature
  • using an air humidifier to add moisture to the air, if dry
  • regularly using protective moisturizers or emollients
  • preventing major temperature changes by using air conditioning when the temperature is above 75ºF (23.8ºC)
  • removing or adding clothing layers if a person gets too hot or too cold, and not using too many bed covers at night

Learn more about the benefits of a humidifier.

Some people are naturally prone to dry skin regardless of their environment. For example, those with atopic eczema may have more permeable skin due to a genetic trait, resulting in lower levels of moisture.

What to do

Doctors recommend that people with eczema keep their skin moisturized. However, it is important to ensure that the moisturizing creams and lotions are preservative- and fragrance-free.

When choosing a moisturizer, look for the National Eczema Association (NEA)’s “Seal of Acceptance” on products. People can also use ointments, such as petroleum jelly, to seal in moisture.

Learn more about which lotions to use to relieve itching from eczema.

Some evidence suggests that sex hormones may influence atopic dermatitis.

A 2019 article notes that female children are more likely to develop atopic dermatitis after puberty. However, before puberty, the opposite is true.

The researchers suggest that this may be due to sex hormones and their impact on the immune system. While testosterone suppresses the T helper 2 cells (Th2) involved in atopic eczema, the female sex hormones enhance their activity.

This may explain why some females find their eczema improves or worsens at certain points in their menstrual cycle or during pregnancy.

What to do

How the hormones affect eczema is largely unavoidable. However, managing symptoms and identifying triggers may help someone who is pregnant prepare for flares and symptoms.

Learn more about eczema and pregnancy.

Some types of bacteria, viruses, and fungi are responsible for some types of eczema. These include:

  • Staphylococcus aureus: People with atopic dermatitis are more likely to have larger numbers of this type of bacteria on their skin. If a person scratches eczema, the bacteria can enter the skin’s deeper layers and cause infection.
  • Malassezia: This type of yeast occurs on the skin of people who have seborrheic dermatitis. It can cause both dandruff and an itchy, flaky rash in areas where the skin gets oily, such as the face.
  • Herpes: The herpes simplex virus that causes cold sores, or oral herpes, can affect more extensive areas of skin. When it does, it causes a type of eczema known as eczema herpeticum.

What to do

If a person has a type of eczema caused by a virus or fungi, a doctor can prescribe medications and topical remedies to treat it. There are also over-the-counter (OTC) treatments, such as antifungal shampoo.

People with eczema should avoid scratching, particularly with unwashed hands or around cracked skin. If pus, swelling, or warmth develops, a person may require antibiotics.

Learn more about infected eczema.

Sweating is another common eczema trigger. This may be due to the skin being moist or because of the increase in body temperature.

What to do

If sweat is a trigger a person can try:

  • keeping cool, where possible
  • avoiding tight clothing, instead opting for light layers that allow a person to adjust how hot or cold they are
  • wearing natural fibers, such as cotton and linen, as these are more breathable
  • avoiding wearing sportswear for prolonged periods after exercise, and wash promptly

Learn about heat-induced rashes.

According to the NEA, around 15% of children with atopic dermatitis also have a food allergy. Atopic dermatitis also often occurs alongside hay fever or asthma.

While eczema is not a symptom of an allergic reaction in itself, people with both eczema and allergies may find the symptoms worsen when they have an allergy.

People with food sensitivities may also notice eczema worsens if they eat certain foods.

What to do

If a person suspects a specific food may be worsening their eczema, they can speak with a doctor about allergy testing. This can detect the foods a person is allergic to, allowing them to avoid them.

Learn about which foods to eat and avoid.

If a person has symptoms without any other apparent trigger, dust mites may be the reason. Dust mites are common, microscopic creatures that live on the components of dust, such as human skin flakes.

Unlike bedbugs, they are not parasites, but some people can have an allergic or sensitivity reaction to their droppings.

Dust mites occur in house dust and soft furnishings. It may not be possible to eliminate them, but people can limit their effect.

What to do

A person can help minimize the effects of dust mites by:

  • using dust mite covers on the pillows and mattress
  • washing all bedding weekly in hot water with a fragrance-free detergent
  • limiting the use of rugs, curtains, plush toys, and soft furnishings
  • dusting and vacuuming the home regularly

What is the link between dust mites and eczema?

Experts have not found a direct link between tobacco use and eczema. But, some 2021 research has suggested that the symptoms of atopic dermatitis, a type of eczema, may be worse in people who smoke compared with those who do not.

The AAD also notes that exposure to tobacco smoke may trigger or worsen symptoms in children.

What to do

A person can help limit their exposure to smoke by:

  • avoiding or quitting smoking, if applicable
  • stopping people from smoking inside the home
  • avoiding going to places where people smoke

If a person’s eczema seems to worsen around pets or other animals, dander may be a trigger. Pets shed skin cells in dander from fur, skin, and the mouth.

What to do

A person can help limit their exposure to dander by

  • brushing pets regularly to remove dander, pollen, and other allergens
  • avoiding grooming pets indoors, if possible
  • ensuring pets sleep in their own beds and not in bedrooms or on furniture
  • vacuuming and dusting the home regularly

How can a person be allergic to cats?

Traffic pollution, pollen, mold, and other outdoor allergens can worsen the symptoms of eczema. It is not always possible to prevent exposure, but some tips may help reduce the risk.

What to do

People can limit their exposure to pollen by monitoring the pollen count in their area.

Here are some tips to help at times when the count is high:

  • keeping doors and windows shut as far as possible
  • using air-conditioning
  • limiting time outdoors
  • asking someone else to mow the lawn and staying away from the lawn for 2 hours after mowing

What is the link between asthma, eczema, and allergies?

Some people find that sunburn or sun exposure worsens or triggers symptoms.

What to do

A person can help prevent sunburn or sun exposure by:

  • applying a fragrance-free, broad-spectrum sunscreen of at least SPF30
  • choosing products containing only these active ingredients: titanium dioxide, zinc oxide, or both
  • staying in the shade where possible
  • wearing clothes that protect the head, face, and body from the sun

Is sun exposure good or bad for people with eczema?

There is currently no evidence that specific foods cause eczema, although individuals may have allergic reactions to specific foods.

Based on anecdotal evidence, some research has suggested that removing products containing white flour, gluten, and nightshades, such as tomatoes, may help, but more research is needed to confirm this. Meanwhile, increasing the intake of vegetables, organic foods, and fish oil appeared to be beneficial.

Irritant foods, such as chilies, may cause inflammation in sensitive skin.

What is the link between diet and food allergies?

What to do

A person can help avoid possible food triggers by:

  • wearing protective gloves when handling chilies and other possible irritant foods
  • trying eliminating individual items from the diet to see if it helps
  • following a varied and nutritious diet with plenty of fresh fruits, vegetables, and whole grains to boost overall health and wellbeing.

Learn about an elimination diet to identify eczema triggers.

A person should consult their doctor if they suspect they have a skin infection. This is particularly true when the infection develops in an area where their eczema tends to flare up.

If a person has noticed their eczema has worsened or is no longer responding to their usual treatment, they may benefit from speaking with a doctor or dermatologist.

A dermatologist can help a person identify the type of eczema they have and prescribe treatments that may be more effective. They can also refer someone for diagnostic tests, such as allergy testing, if necessary.

If a rash appears suddenly, spreads quickly, or shows signs of infection, a person should contact a doctor as soon as possible.

Learn more about allergic rashes and reactions.

Here are some questions people often ask about eczema triggers.

What foods should I avoid if I have eczema?

Some people have found it beneficial to cut out foods containing white flour, gluten, and nightshades, such as tomato, but increase the overall intake of vegetables, organic foods, and oily fish. However, more research is needed, and people should speak with a doctor before changing their diet.

Why did my eczema start suddenly?

Eczema can start suddenly in adults, and it is not clear why this happens. Possible causes include hormonal changes and the skin becoming drier with age. Or, there may be a new trigger, such as environmental changes or additional stress.

How can I get rid of eczema symptoms fast?

Avoiding triggers and moisturizing the skin may help reduce symptoms, but this can take time. Over-the-counter and prescription creams and medication may also help if home remedies do not improve symptoms.

There are many potential causes for eczema flare-ups, including weather changes, irritants, allergens, and water. Identifying triggers can help a person manage their eczema and reduce the symptoms.