Psoriasis and eczema are chronic skin ailments that produce itchy, red patches. While there are some similarities between them, there are also several distinguishing characteristics.
Location
Either disease may appear anywhere on the body. Psoriasis usually appears on the backs of the elbows and on the knees, while eczema is found on the insides of the elbows and behind the knees.
Appearance
Psoriasis has thick, red plaques with silvery scales that exhibit pinpoint bleeding when the plaque is removed, according to Merck Manuals Medical Library. The patches usually have sharp margins. Eczema is extremely itchy with a rash-like appearance. Crusting and scaling of eczema may weep and ooze clear fluid.
Age of Onset
While either disease can occur at any time of life, psoriasis usually has an adult onset. Eczema generally begins in infancy or childhood.
Cause
The National Institute of Arthritis and Musculoskeletal and Skin Diseases describes psoriasis as having a genetic predisposition, along with T-cell dysfunction. Eczema has a genetic component and immune dysfunction, but it is generally associated with allergic conditions like asthma and hay fever.
Treatment
There is some overlap in treatment regimens, but psoriasis treatment can involve coal tar and vitamin A and vitamin D creams. Antibiotics and antihistamines are sometimes used for eczema, but not for psoriasis.
