You know that eczema can cause symptoms like itchy rashes, blisters, and dry, cracked skin but may not realize that this common skin condition can also cause lighter or darker patches to appear on your skin.
The condition is called eczema pigmentation and it occurs during periods of active eczema (or flares), often as a result of scratching the rash.
There are two different types of eczema pigmentation: hypopigmentation and hyperpigmentation. In hypopigmentation, affected patches of skin become lighter than your normal skin tone. Hyperpigmentation causes the opposite reaction, turning patches of skin darker than your normal skin tone.
Although the symptoms of eczema, including itchiness, swelling, and oozing patches of skin, are similar whether you have dark skin or light skin, both hypopigmentation and hyperpigmentation are more common in darker skin. In fact, redness and inflammation often go undetected in darker skin and take longer to resolve.
Understanding Different Kinds of Eczema Pigmentation
Inflammation stimulates the activity of melanocytes, the cells that give skin their color, boosting the production of skin pigment and causing darker patches of skin, or hyperpigmentation. Every time you scratch your skin, more melanin is released and the patch of skin gets darker. Since those with darker skin have more melanin, the reaction causes even more pigment production.
Darker patches of skin (hyperpigmentation) are a result of post-inflammatory pigmentation or lichenification.
Post-inflammatory pigmentation: After an eczema flare subsides, skin might be darker in the places where eczema lesions have healed. This is called post-inflammatory pigmentation and it’s also more common in darker skin (though it can affect all skin tones).
While the dark patches caused by post-inflammatory pigmentation will eventually fade, they can remain on the skin for months and may last even longer. Research shows that post-inflammatory pigmentation lasted up to 5 years in more than 22% of diagnosed cases. Daylight can make post-inflammatory pigmentation worse, so sun protection is essential.
Lichenification: Eczema is known for causing itchy rashes but scratching or rubbing the affected areas can thicken the skin and increase skin markings, causing darker or hyperpigmented patches. These markings, called lichenification, have a dry, scaly appearance and range from dark pink to slate gray, depending on your skin color. Lichenification is most common in areas like the front of the feet, back of the neck and scalp, wrists, forearms, lower legs, and genitals.
Lighter patches of skin (hypopigmentation) are called pityriasis alba.
Pityriasis alba: The name, which means fine scale and pale color, causes patches of eczema that are pink and dry. It’s also more common in darker skin. Pityriasis alba is made up of multiple -- up to 20 -- round or oval patches of skin on the face, neck, shoulders, and upper arms that often appear after sun exposure. These patches tend to resolve on their own, but it can take months for your skin to return to its normal color.
Eczema pigmentation is often mistaken for scarring. If eczema patches become infected, they can leave scars, but hypopigmentation and hyperpigmentation have a totally different cause than scarring; the pigment changes affect only the upper layer of the skin (called the epidermis) and don’t leave scars. Unlike scars, which are permanent, pigment changes are temporary and often resolve on their own.
Preventing Eczema Pigmentation
There are no surefire strategies to prevent hyperpigmentation and hypopigmentation, but reducing the itch can help reduce the risk.
Scratching -- and the inflammation it causes -- can affect pigmentation so treatment starts with controlling eczema flares. Common treatments to help stop the itch include steroid medications, antihistamines, and prescription creams. Cool compresses and moisturizers may also help reduce itchiness.
Exposure to the sun makes post-inflammatory pigmentation worse but sunscreen can help. One study found that using an SPF-60 broad spectrum sunscreen lowered the likelihood of dark skin patches from post-inflammatory pigmentation.
Treating Eczema Pigmentation
Since the light and dark patches on your skin often resolve on their own, there are no specific treatments for eczema-related pigment changes.
Your doctor may recommend lotions to reduce itchiness and help your skin retain moisture or topical steroid creams to decrease inflammation. There is also some research that shows applying a triple combination cream that contains fluocinolone acetonide, hydroquinone, and tretinoin, for 8 weeks was linked to higher rates of success for clearing post-inflammatory hyperpigmentation than other treatments.
Changes to your skin pigment can linger even after your eczema has been treated. If this happens, your doctor may recommend stopping topical steroids because long-term use of these creams can cause permanent lighter patches of skin, or hypopigmentation.
Noticing lighter or darker patches on your skin may be distressing but, if you have eczema, hypopigmentation and hyperpigmentation are common. Work with your doctor to make sure your eczema symptoms, especially itchiness, are well controlled to help decrease the likelihood of pigment changes and remember, eczema pigmentation often resolves on its own and is no cause for concern.