Various factors can contribute to an eczema flare-up, including allergens, stress, and cold weather. Identifying potential triggers can help people avoid or manage their eczema 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 for a flare-up may be more difficult.

This article will look at nine of the most common causes of eczema flare-ups and how a person can reduce their exposure to them.

The palm of someone's hand, covered in moisturizer due to an eczema flare-up.Share on Pinterest
Jonathan Knowles/Getty Images

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 here.

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 fragrance, 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 here.

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 make eczema worse. It is also a risk factor for mental health conditions, including depression and anxiety.

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 trouble 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.

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

Learn more about the benefits of a humidifier here.

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 peopel who have 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 here.

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 develop, a person may require antibiotics.

Learn more about infected eczema here.

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:

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

Learn about heat-induced rashes here.

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 here.

A person should see 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, see a doctor as soon as possible.

Learn more about allergic rashes and reactions here.

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.