What is eczema, and what are its causes?
Eczema is a skin condition which can affect people at any age. You likely know someone who has it, as it is very common, especially in children: 1 in 5 children is affected.
Fortunately, eczema is most often benign and is not contagious. That said, however, we still want to find ways to relieve any discomfort and reduce its potential psychological impact.
How can you tell if you have eczema?
What are the signs and symptoms?
Eczema is a type of inflammation which causes skin to itch. The often intense desire to itch is thus the most distinctive, although not the only, sign.
Eczema appears as red patches. Note that the edges of these patches are not well defined, making it difficult to determine where they begin and end exactly (unlike psoriasis, for example).
The appearance of these patches changes over time and depending on the severity of the condition. At the start of onset, they are often swollen and sometimes have little blisters that open on the surface. As a result, they may ooze and form scabs. They can also become thick, rough and very dry, sometimes even forming painful cracks.
In the case of atopic eczema, patches are associated with skin dryness.
List of eczema symptoms
- Red patches (erythema)
- Swelling (edema)
- Small blisters (vesicles)
- Oozing (from blisters opening)
- Thickening of the skin (lichenification)
- Marks from scratching (excoriation)
- Dry skin (in atopic eczema)
Not all eczema symptoms will manifest necessarily, or they may appear at different times.
What are the causes of eczema?
The three main causes of eczema
The first myth to clear up is that eczema is contagious—this is false. In order to get to the truth, and thus adopt good treatment habits, we should start by having a good understanding of the different types of eczema.
Let’s start with the causes. Eczema has three possible causes: atopic skin, a contact allergy or sometimes a simple irritation.
Atopic skin: a genetic condition
Hypersensitivity to the environment
People with atopy may experience atopic eczema, usually within the first months of life. This type of eczema presents as alternating periods of flare-ups and remission which can last several years, sometimes a lifetime (although rare).
It is caused by a malfunction in the skin, which is no longer able to act as a proper barrier and becomes inflamed more easily.
There is no cure for atopic eczema, but flare-ups often disappear on their own after a few years.
What is this infamous atopy?
Atopic skin is hypersensitive to the environment. It is also hereditary, meaning you will likely find other members of the same family with atopy. Atopy can lead to more than just eczema: this heightened sensitivity can also trigger asthma and hay fever (allergic rhinitis).
Practically speaking, what are the triggering factors for atopic eczema?
Seeking advice from a dermatologist greatly improves your chances of identifying the cause of your atopic eczema. Determining the triggers for flare-ups, however, can prove more difficult. Why does eczema come back after so many months of remission? Why today and not yesterday? In practice, a great number—and often a combination—of factors can trigger inflammation. In other words, there is no single culprit, but several.
Below are the factors which can trigger or aggravate atopic eczema (opinions differ, however, as research on this topic is advancing every day):
- temperature variations
- certain clothing
Are your earlobes showing signs of eczema after wearing costume earrings? This is clearly an allergic reaction. As a hairdresser, do you suffer from eczema on your hands? This is clearly an allergy caused by contact with hairstyling products. In fact, many cases of contact eczema, especially on the hands, are caused by contact with a substance handled at the workplace.
As you can see, some types of eczema are caused by a contact allergy. It may be triggered by a personal care product or hair dye, for example, as well as an object such as a musical instrument, footwear or even a bandage.
The good news is this type of eczema is reversible. Simply eliminate the triggering substance and all products containing the allergen to restore skin to its normal state. Of course, you will need to consult a professional to identify and confirm the allergy through allergy tests.
Consider indirect contact
Imagine a mother uses a hand cream. A few hours later, her baby is covered in red patches. The baby has had an allergic reaction to a cosmetic product used by his mother, who naturally touches him several times throughout the day. Contact with the allergen occurs indirectly by way of the mother.
In some cases, an allergen can travel through the air and reach your skin, or can even be transferred from your own hands (e.g.: you can have eczema on your neck if you are allergic to your nail polish and touch your neck).
Not all skin reactions to products or objects are contact allergies. This is especially true for the hands, where you may experience a simple irritation caused, for example, by a detergent or degreasing agent. This is known as irritant eczema.
Some scientists argue that this is not a form of eczema but simply an irritation dermatitis: the classifications are not universal.
Redness can also be a sign of a simple irritation, without being full-blown eczema, especially with personal care products and the like.
Eczema is not caused by poor hygiene, a contamination, parasite or even stress (which is simply an aggravating factor).
Diseases most often mistaken for eczema
The diseases below are often mistaken for eczema because they all involve itching and/or red patches on the skin:
- Seborrheic dermatitis
- Some mycoses
- Other rarer diseases (dermatitis herpetiformis, mycosis fungoides, etc.)
Are you sure it’s eczema? Here are the major differences between eczema and these other diseases.