Psoriasis vs. Eczema: Differences, Images, Treatment

• Psoriasis and eczema both present as patches of red, scaly and itchy skin, but psoriasis plaques tend to be thicker
• Psoriasis is an autoimmune disease, while eczema is triggered by genetic or environmental factors
• Neither condition is contagious
• Treatments for both are similar, but eczema sometimes requires antibiotics due to infection from open sores

To the untrained eye, psoriasis and eczema are quite similar in appearance. Patches of red, dry skin develop which can cause itching, embarrassment, and have an impact on quality of life. 

And while they share some of the same characteristics and treatment options, the underlying cause of these two common skin conditions differs and determines the best approach to reducing future flare-ups.

Why Is Eczema Confused With Psoriasis?

Mistaking eczema for psoriasis is common, as both are inflammatory skin conditions and are similar in appearance. The two not only share similar symptoms, but they frequently develop in the same areas of the body, such as the scalp or hands. 

While those are two of the more common sites for flare-ups, both conditions can form anywhere on the body. They also share some common triggers, including cold, dry air and allergens in the environment. 

Can you have both at the same time?

Yes, you can. This is known as a condition called eczematous psoriasis. This typically presents as an eczema rash and psoriatic lesions in specific areas such as behind the knee, the crook of the elbow, or other folds in the skin – areas where sweat and moisture can get trapped and irritate the skin. This overlapping condition also tends to cause more itching than psoriasis alone due to increased inflammation.

Understanding Psoriasis

Psoriasis is an autoimmune disease – a condition in which the body’s immune system mistakenly attacks healthy cells. Plaque psoriasis is one of several types of psoriasis and affects 80–90% of people who develop psoriasis.

In this condition, the body produces skin cells at an accelerated rate. Normally, it takes weeks for new skin cells to form under the skin and migrate up to the skin’s surface, but in plaque psoriasis, the entire process occurs over just a few days.

 As a result, skin cells accumulate and form thick, red patches, called plaques. These plaques are often covered with silvery scales that cause itching and pain.

Small, scaly bumps develop in mild cases; dry skin cracks and bleeds in severe cases. Other psoriasis symptoms include ridged fingernails and toenails, as well as stiff, swollen joints.

Science hasn’t developed a deep understanding of why some people develop psoriasis. Research suggests that having psoriasis means you are more likely to have other autoimmune diseases. While this is a lifelong condition, an individual can be symptom-free for years.

Environmental factors or lifestyle choices can trigger psoriasis flare-ups. Among the more common triggers are:

• Allergies
• Cold, dry air
• Drugs
• Heavy alcohol use
• Infection (particularly strep throat)
• Injury to the skin (such as sunburn or a bad cut)
• Stress
• Tobacco

Where on the body is psoriasis likely to appear?

Psoriasis can affect any part of the body, but especially in those areas where skin rubs against clothing, such as:

• Elbows
• Knees
• Lower back
• Soles of the feet

The hands are also common sites for psoriasis flare-ups as a result of frequent hand washing and because of the wear and tear on busy hands throughout the day. Anything that puts stress on the hands or causes dryness raises the risk. Psoriasis that forms on the scalp is associated with psoriatic arthritis, a type of psoriasis that causes inflammation of the joints.         

Understanding Eczema

Just as there are different types of psoriasis, there are also several kinds of eczema. The most common is called atopic dermatitis, and it usually first appears in young children, although symptoms can show up at any age.

An atopic dermatitis flare-up produces dry, itchy skin and brownish or red patches. Small, fluid-filled bumps often develop that become crusty when scratched.

Researchers have identified several factors that contribute to the development of atopic dermatitis. Among potential contributing factors are:

• Genetic mutations that affect skin health
• Unhealthy response of the immune system
• Low levels of certain bacteria in the microbiome that protect the skin
• Inflammation that affects the nerves in the skin

Where on the body is eczema likely to appear?

Atopic dermatitis flare-ups usually appear where the limbs bend and skin folds trap moisture, causing irritation.  Typical spots for eczema flare-ups include:

• Behind the knee
• Crook of the elbow
• Neck
• Wrist and hand

Eczema, which can be triggered through contact with an allergen or other irritant in the environment, can produce a rash anywhere on the body.

How to Tell the Difference Between Psoriasis and Eczema 

To determine whether a rash is a sign of psoriasis or eczema, it is advised to see a dermatologist. They will consider the number of flare-ups, the thickness of the plaques, the patchiness of the rash and determine if fluid-filled blisters are present.

Scaly skin

A strong indication of psoriasis is the presence of well-defined patches of red and silver scales. While this symptom is also seen with eczema, eczemic rashes tend to appear as a scattering of bumps.

Bumps or flakes

Staphylococcus bacteria is normally present on the skin of most healthy people, but if it penetrates deep into the skin and enters the bloodstream, a staph infection can develop. 

Eczema flare-ups are therefore commonly associated with yellow-colored crusts caused by this staph bacteria. Bumps containing the bacteria break open and crust over quickly. 

Psoriasis flare-ups don’t contain fluid-filled or crusty little bumps. Instead, it produces dry flakes that sheds off the body.

One flare-up or two?

Psoriasis and eczema also differ in the number of rashes that appear at one time. Psoriasis tends to appear symmetrically on the body such as on both knees or both elbows.

Eczema, however, can show up on just one arm or leg.  And unlike psoriasis outbreaks, eczema tends to migrate, clearing in one area, and developing elsewhere.

Itchy skin

The degree of itchiness also offers clues about the cause of your flare-up. Psoriasis tends to be much less itchy than eczema. Rare types of psoriasis, however, can cause a burning sensation.

Over-the-Counter vs. Prescription Treatments 

Certain commercial and prescription treatments are effective in treating both skin conditions. For more serious cases, however, doctor-prescribed medications and other therapies specific to each condition will be necessary.

Over-the-counter treatment options include:

• Topical corticosteroid creams, such as Cortizone-10, reduce mild inflammation and symptoms 
• Moisturizing creams and ointments, which ease symptoms and lower the risk of future flare-ups on areas of dry skin

Prescription medications and therapies include:

• Immunosuppressive drugs, such as cyclosporine and methotrexate tamp down the body’s immune system response. They are prescribed for moderate to severe cases of psoriasis and severe cases of eczema that cover widespread areas of skin
• Phototherapy, also known as light therapy, emits various wavelengths of ultraviolet light to target specific areas or the entire body  
• For psoriasis in particular, anthralin is commonly prescribed to slow the growth of new skin cells. Synthetic versions of vitamin D, including calcipotriene and calcitriol, also effectively slow skin cell growth and are often combined with topical corticosteroids.

For severe cases, an FDA-approved injectable drug, dupilumab, controls the inflammatory response responsible for eczema flare-ups. Two prescription-strength topical creams – tacrolimus and pimecrolimus also reduce inflammation associated with eczema. Antibiotics are also used to address bacterial infections.

Researchers are also finding encouraging results, including clearer skin and less itching, with JAK-STAT inhibitors and PDE-4 inhibitors.  

Takeaway 

Psoriasis and eczema are both inflammatory skin conditions that result in red patches of scaly skin. Psoriasis flare-ups are usually less itchy than eczema rashes, but they produce thicker scales. Psoriasis is an autoimmune disease, like rheumatoid arthritis, while eczema is caused by genetic or environmental factors, as well as abnormal responses of the body’s immune system. 

While there is no cure for either condition, there are several prescription and OTC treatments designed to ease symptoms and reduce the intensity of future flare-ups.