Understanding Eczema Part 1: What exactly is eczema?


“Eczema” and “dermatitis” are two terms that are often used interchangeably.  Many skin conditions are diagnosed as eczema when they aren’t and there are many forms of dermatitis, each with their own unique details.  This post is my attempt to straighten out this information (and misinformation) for you.  I will cover eczema according to Traditional Chinese Medicine in future posts.

Some sources (dermatology texts, various medical publications and organizations)  claim that eczema is the big umbrella term that is used generally to mean any of the various forms of dermatitis.  Yet other sources say the exact opposite – that eczema is but one type of dermatitis (this is the view I will take for this series of posts about eczema).  With all the variations on what “eczema” means, it is no wonder there can be much confusion for the patient!

“Dermatitis” means “inflammation of the skin”.  So eczema and dermatitis refer to a group of patterns that involve non-infective inflammatory reactions of the skin.  There are several types of dermatitis.  The most common are: contact dermatitis (includes irritant contact dermatitis, allergic contact dermatitis, allergic contact dermatitis due to plants, and non-allergic contact dermatitis), atopic dermatitis (this is the dermatitis most commonly referred to as “eczema”), dyshidrotic eczematous dermatitis (a type of hand and foot dermatitis, a.k.a. as “Pompholyx” or “vesicular palmer eczema”), neurodermatitis (a.k.a. lichen simplex chronicus), seborrheic dermatitis (a.k.a. “cradle cap” in infants), and photodermatitis.  Photodermatitis refers to inflammation of the skin that occurs when a topically applied substance is then exposed to sunlight.  This includes phytophotodermatitis (a skin reaction from exposure to plants + sunlight) as well as phototoxic and photoallergic dermatitis.

Of the above-mentioned types of dermatitis, the types that are most popularly referred to as “eczema” are atopic dermatitis and allergic contact dermatitis.  Personally, I reserve use of the term “eczema” to be used interchangeably only with atopic dermatitis.  The reason I make this distinction is that the immune process involved in the development of each disease is based on different mechanisms and they have different long-term effects.  Allergic contact dermatitis is a type IV hypersensitivity reaction and the inflammation in the skin can be completely healed as long as exposure to the offending agent is identified and avoided.  Atopic dermatitis/eczema, however, has a much more complicated etiology (multiple underlying causes) and is associated with type I hypersensitivity (which is an IgE antibody response).    Atopic dermatitis/eczema tends to become a chronic condition and is much more complex to treat.  This is the condition I refer to as “eczema” and this is the condition we will continue to discuss in this and future posts.  I will use the term “eczema” from this point forward but keep in mind that other sources may use any of the following terms interchangeably:  “eczema”, “atopic eczema” and “atopic dermatitis”.  They are all the same thing.  In addition, other health care providers may use “eczema” to mean any of the dermatitis rashes listed above, so if you are unsure of your exact diagnosis, ask your provider to clarify terms for you or consider getting a more specific second opinion.

Now that we are on the same page about the terminology (I hope!) we can sum up what eczema is.  Eczema, also known as atopic eczema or atopic dermatitis, is an acute, subacute or chronic (relapsing) inflammatory skin condition that is characterized by itching (pruritis).  The lesions range from pink to red, and when scratched will become weepy and crusted.  As the condition progresses, dryness of skin becomes more predominant and lichenification (hyperplasia of the skin) can occur due to rubbing the sites.  The condition usually begins in infancy and continues to recur in adulthood.  Diagnosis of eczema is made based on clinical presentation, patient history, and (possibly) blood tests since IgE serum levels are elevated in many cases.

This is a lot of information to digest, so I will break up the topic of eczema into several posts.  Coming up in the next post, we will cover the causes of eczema (from a western/scientific viewpoint) and how it develops.  Later, we will talk about eczema from the perspective of Chinese Medicine (that alone might take a few posts).  After that, I will comprise a list of things YOU can do to help heal your eczema.

Tags: allergic reaction, atopic dermatitis, atopic eczema, contact dermatitis, dermatitis, dermatology, eczema, exzema, herbal skin care, natural skin care, rashes, skin care, skin rash

Topics: Allergies, Eczema, Rashes

Publish Date: September 27, 2010     *Articles may include updates since original publishing.

About the Author ()

Diana Hermann is a licensed acupuncturist and board certified in Chinese Herbal Medicine. She received her Master Degree in Acupuncture and Oriental Medicine from the Oregon College of Oriental Medicine in Portland, OR and trained in China at the Nanjing University of Traditional Chinese Medicine. Diana treats patients in her Fort Collins, Colorado clinic and hand crafts herbal skin care products for her company Zi Zai Dermatology. In 2015, she completed the Diploma In Chinese Medicine Dermatology program from Avicenna in London, UK. She completed the program for a second time in 2019 in Chicago.

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  1. Understanding Eczema Part 4: Patterns and Phases | Zi Zai Dermatology's Blog | November 16, 2010
  1. Thanks, Diana, for clarifying these terms. No wonder it seems that there’s so much contradictory information out there–they’re talking about different things! My son definitely had eczema, as you define it. Looking forward to your future posts.

    • Clearly defining terms sure improves communication – between doctors and patients and between those of us in the healing community. If we cannot communicate effectively, it makes improving the situation much more difficult. Thanks for reading the blog – I will be adding a bit more info to this post as I left out some important basics that should be included here before we move on to the next post.

  2. Just for the record (because my medical opinion is not the only one):

    The National Eczema Association defines eczema as follows:

    “Eczema is a general term for any type of dermatitis or “itchy rash”. There are several skin diseases that are eczemas; a partial list of eczemas includes:

    * atopic dermatitis
    * contact dermatitis
    * dyshidrotic eczema
    * nummular eczema
    * seborrheic dermatitis

    All types of eczemas cause itching and redness and some will blister, weep or peel.”

    This was quoted directly from their website at http://www.nationaleczema.org/living/eczema_quick_fact_sheet.htm

  3. Brandy says:

    LOVE the post. Also, love your organization for breaking down the topic. Am looking forward to following the eczema postings.

  4. G.H. says:

    I am so glad to read your explanation of the different terms, because I was pretty confused by what I have read on other medical/reputable sites.
    I had seen the definition of eczema as a general, umbrella term for all dermatitis (including allergic contact dermatitis and irritant contact dermatitis), and I had also seen mentions of eczema as only being a specific type of dermatitis (atopic dermatitis).
    It’s good to know that the term really is used in different ways by different medical professionals, so one needs to make sure to determine which definition is being used in each situation it’s being discussed (for example, in a casual conversation between friends, in a medical reference source that describes common causes and treatments, at a medical appointment with one’s doctor).

    • You know, I wrote this post several years ago. For whatever reason, I got stuck using the term “atopic eczema” now instead of “atopic dermatitis”. It is the same thing. There are variants of atopic eczema and there are various types of dermatitis that exist as a variant of atopic eczema but can develop in people who are not atopic. An example is nummular eczema. In this form of eczema, the lesions are discoid-shaped (round like a coin). A person with atopic eczema can have lesions that present in this format. But someone who is not atopic (someone who does not have an immune-mediated response) can also develop coin-shaped eczematous lesions. The difference? The atopic version can be more stubborn and take longer to treat.

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