Psoriasis and eczema may present with similar symptoms: discolored skin, rash, and itching and burning sensations. Though they are sometimes mistaken for each other, in the majority of cases, the difference is striking to a health care provider.
“Usually, it is easy to distinguish the two. However, there are some sites, such as palms and soles and inguinal [groin or genital] areas where a rash could look like eczema, but it is psoriasis,” says Gil Yosipovitch, M.D., Director of the Miami Itch Center, Miami, Florida, and a professor in the Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miller School of Medicine, University of Miami.
Perhaps it is best if we begin with accurate definitions of both psoriasis and eczema:
- Psoriasis is a chronic immune-mediated disease associated with systemic inflammation that can lead to comorbidities like cardiovascular disease, type 2 diabetes, anxiety, and depression.
- Eczema, according to the National Eczema Association, “is the name for a group of conditions that cause the skin to become itchy, inflamed, or have a rash-like appearance. There are seven types of eczema: atopic dermatitis, contact dermatitis, dyshidrotic eczema, nummular eczema, seborrheic dermatitis, and stasis dermatitis.”
Psoriasis more commonly first occurs in adults ages 20 to 30 years old with a second peak around age 60, and among adults in the U.S. about 3% live with psoriasis. Only about 1% of children are diagnosed with psoriasis, while according to the National Eczema Association, atopic dermatitis – the most common type of eczema – typically begins in childhood and affects more than 9.6 million children and about 16.5 million adults. 
The National Health and Nutrition Examination Survey found that 19.3% of African-American children have atopic dermatitis, compared with 16.1% of white children and 7.8 percent of Asian children. 
Plaque psoriasis or psoriasis vulgaris is the most common type and typically presents on lighter skin as red plaques with silvery scales.  On skin of color, plaque psoriasis can appear as purple or discolored skin. The plaques may be thick, raised, cover a large area of skin, and usually have very defined borders. The plaques can occur in any location but often present on the trunk, knees, or elbows, Dr. Yosipovitch explains. The plaques may also present on the scalp or hairline.