Although both have characteristic dry, red patches of skin, eczema causes more itching and swelling, while psoriasis causes the skin to peel off in patches.
Eczema and psoriasis are both incurable inflammatory skin diseases. Because some of the symptoms are similar, these two diseases in infants and young children are often misdiagnosed. Eczema and psoriasis can be distinguished through factors such as the affected skin area, skin characteristics and level of itching.
Location
Eczema and psoriasis both cause dry, inflamed patches of skin, symptoms that manifest in flare-ups. However, eczema often appears on the elbows and back of the knees (folded skin surface). Psoriasis is often on the outside of the forearms and elbows or the front of the knees and legs (flat skin surface).
Psoriasis can also occur on the scalp, face, lips, ears, neck, navel, arms, legs, feet, hands, ankles and lower back. These areas can also have eczema but it is usually not as severe as psoriasis.
Both of these diseases can cause ridges, discoloration, and thickening of fingernails and toenails. However, only psoriasis causes small holes in the nails (pitting).
Skin characteristics
Peeling is the main sign of psoriasis, and people with eczema rarely experience this condition. Eczema can cause rashes, swelling, papules, blisters, and dark, thick, rough areas of skin (lichenification). People with severe eczema may experience oozing and crusting in the affected skin area.
While psoriasis presents as well-defined patches of red skin, covered with fine silvery-white scales. These plaques bleed easily when scratched and leave tiny blood spots.
Characteristics that help distinguish eczema and psoriasis. Graphics: Verywell Health
Degree of itching
People with psoriasis may experience mild itching, but the itching caused by eczema is often severe. The causes of itching in the two diseases are different. In psoriasis, itching occurs because inflammation in the skin affects nerve receptors called nociceptors.
Pain receptors are also stimulated in eczema, but the irritation is aggravated by an antibody called immunoglobulin E (IgE) that is associated with allergies. People with eczema have IgE antibodies, but people with psoriasis do not.
Reason
Researchers believe that eczema is caused by an overactive immune system. They cause the body to produce too many white blood cells called T cells. These cells trigger an inflammatory response to protect the body against infection. Inflammation causes cells in the lymph nodes to pump IgE into the blood. IgE causes cells in the outer layer of the skin (epidermis) to swell and skin changes such as lumps and thickening occur.
Psoriasis is an autoimmune disease, meaning the immune system sees normal skin cells as harmful and attacks them by sending T cells. T cells target new (immature) skin cells. called keratinocytes. Inflammation causes these cells to divide more quickly.
Normally it takes 28-30 days for new skin cells to replace, but in psoriasis, it takes only 3-5 days. Because skin cells are produced faster than the body can remove them, they are pushed to the skin’s surface and lesions form.
Trigger factor
Both genetic and environmental factors seem to play a role in causing eczema and psoriasis. Because eczema involves IgE antibodies, common allergens can cause flare-ups, including dust mites, pet dander, pollen, and mold. Besides, there are certain foods such as dairy products, eggs, nuts, soy products, and wheat.
The environmental factors that can trigger psoriasis are not as specific as eczema. However, many factors that trigger flare-ups of other autoimmune diseases also cause psoriasis, including infections, alcohol, tobacco, skin trauma, and certain medications.
Both eczema and psoriasis can be caused by extremely cold and dry weather or extremely hot and humid weather. Stress is also a common trigger for both conditions.