Seborrheic dermatitis and psoriasis are both conditions marked by reddened skin with scales. This often makes them difficult to distinguish from one another. They are different, however, when it comes to the appearance of the scales and the parts of the body on which they are most common. These skin conditions also differ when it comes to how challenging the scales are to remove and in regard to certain other symptoms, such as joint stiffness. As far as similarities are concerned, however, they can both cause you to feel itchy and sore but neither is contagious.
You may have a difficult time telling the difference between seborrheic dermatitis and psoriasis because the two are similar in appearance. They are both marked by the appearance of scales. If you have either of these skin conditions, your skin is likely to become reddened and covered with scales. When you have psoriasis, however, the scales often take on a silvery look while seborrheic dermatitis, also referred to as seborrhea, is often marked by scales that appear yellow or white.
Other differences in the scales of these conditions involve oiliness and removal. If you have seborrhea, the scales may appear greasy, for instance. Likewise, the scales you develop because of seborrhea often prove easy to remove while those that appear because of psoriasis may bleed if you attempt to remove them.
A major difference between seborrheic dermatitis and psoriasis is often location: both of these skin conditions commonly affect the scalp, but seborrheic dermatitis usually stays within the hairline while psoriasis is the more likely of the two to extend beyond the hairline. They can, however, affect other parts of the body as well. For instance, psoriasis can affect any area of skin on the body, but is most likely to form on your back, elbows, and knees. Seborrhea, on the other hand, is most likely to affect the back, face, and upper chest. Additionally, other areas of your body that have numerous oil glands may prove vulnerable to its effects.
Both seborrheic dermatitis and psoriasis can be uncomfortable. Each of these conditions can cause the skin in the affected areas to feel itchy and sore. Psoriasis, however, is often associated with swelling of the joints as well. You may also notice that this condition causes your joints to feel stiff. Additionally, both of these conditions may cause you to feel embarrassed about your appearance, but neither is contagious.