Psoriasis and eczema are separate skin conditions, although they share some similar symptoms. Eczema is more commonly found in babies or young children and, unlike psoriasis, may go away over time. It’s uncommon — but possible — to have both eczema and psoriasis at the same time.
The most common form of psoriasis generally appears as scaly patches of dry skin. Depending on your skin tone, the patches may be red, purple, brown, or gray, with an overlying silver scale that may crack and bleed.
Additionally, although both conditions cause itchy skin, the itching associated with eczema tends to be more extreme and almost universal for people with eczema.
Read more about psoriasis symptoms.
While both psoriasis and eczema on the scalp have commonalities such as itching and discolored skin, eczema does not usually appear as dry or with such thick scales. Additionally, eczema scales on the scalp have more of a whitish or yellowish hue versus the silvery color common in psoriasis.
Psoriasis is typically found on elbows and knees, but a person with scalp psoriasis may find patches extending to the forehead, ears, and other areas close to the face. Eczema may also be found on the face and appears as scaly, dry patches without the silver scale. In both cases, there can be extreme itching and discomfort.
Eczema is more often found in folds near the joints, such as the inside or crook of the elbows. On the other hand, psoriasis is commonly found on the elbow itself.
Eczema is commonly found on the palms of the hands because of exposure to soaps, animals, and other allergens. Psoriasis can be found on the back of the hands and on the palms, knuckles, and nails.
Psoriasis is often found on the knees and legs. The type of psoriasis dictates the size of the spots, from smaller and widespread (guttate psoriasis) to larger plaques (plaque psoriasis). Eczema on the legs tends to form where the skin folds, such as behind the knees, whereas psoriasis is usually on the knee itself.
Although the skin symptoms of psoriasis and eczema can look and feel similar, the conditions are very different below the surface of the skin. Eczema is frequently related to allergies. Many people with eczema also have food allergies, seasonal allergies, and asthma.
Psoriasis is a systemic disease — it affects the whole body. Psoriasis causes inflammation, fatigue, and other symptoms. About 30 percent of people with psoriasis develop psoriatic arthritis, which can cause progressive joint damage and lead to disability. Psoriatic disease can also cause uveitis (eye inflammation), which can result in loss of vision.
Eczema and psoriasis are caused by overactivation of different inflammatory pathways within the immune system. The cause of psoriasis, while not completely understood, is an autoimmune reaction, in which the immune system responds to a trigger and recruits many inflammatory cells into the skin.
The cause of eczema isn’t clear, but it’s thought to be an extreme sensitivity — sometimes caused by an allergy — to certain triggering substances. It may also be caused by a defect in the proteins that form the skin’s barrier. Common triggers for eczema flare-ups include animals, fabrics, soaps, metals, and certain medications.
In other words, psoriasis is caused when your immune system attacks itself, and eczema is caused when your immune system overreacts to an outside substance.
Psoriasis is usually diagnosed when a dermatologist performs a visual exam and takes your medical and family history. In some cases, the doctor may do a biopsy (remove a small piece of skin for laboratory testing) to confirm the diagnosis.
Read more details about psoriasis diagnosis.
Similarly, eczema is typically diagnosed by observing the skin and asking questions about medical and family history. A biopsy may also be done to help diagnose eczema. A patch test (attaching samples of different substances to the skin with tape) may be performed to see if the itchy rash is caused by an allergy to an external contact.
In some cases, genetic testing may be needed to differentiate between psoriasis and eczema.
Both psoriasis and eczema are treated by adjusting the immune system’s response. Topical corticosteroids are commonly used to treat both conditions because both lead to inflammation of the skin. The effects of topical medications are mostly limited to the skin.
Keeping skin moisturized can help control eczema. In severe cases of eczema, it may be necessary to take systemic oral medications such as methotrexate or mycophenolate mofetil. More recently, the biologic dupilumab (Dupixent) was developed. This drug is injected twice a month to control inflammation.
Because psoriasis is a chronic (ongoing) autoimmune disease that can cause systemic symptoms and progressive joint damage, it’s important to calm the immune system throughout the body to control inflammation and reduce autoimmune attacks on the skin and joints.
Systemic treatment options for psoriasis include immunomodulators, such as methotrexate, and biologic drugs, such as etanercept (Enbrel), adalimumab (Humira), ustekinumab (Stelara), and bimekizumab-bkzx (Bimzelx), which are injected into the skin. More than 10 biologic medications target the pathways associated with psoriasis.
Phototherapy, or light therapy, may also be helpful in some cases of psoriasis. If you have eczema or psoriasis, talk to your dermatology provider about your treatment options.
Read more about psoriasis treatments.
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