For most people, the skin is the only manifestation of their psoriasis. However, it is useful to be aware of less common manifestations of psoriasis that occur else-where in the body. Aside from the more common nail psoriasis and psoriatic arthritis, there are other places that psoriasis may rarely appear. Mucous Membranes Psoriasis sometimes affects the mucous membranes of the lips, inside of the mouth, and the tongue. In rare cases, people may have psoriasis on or in the mouth. When psoriasis is on the tongue, it may have jagged borders separating areas of lighter and darker color, much like a map.
This characteristic appearance has led to the term “geographic tongue,” which can happen in people with or without psoriasis. Joints The joints, especially those in the hands, may be affected by psoriasis in a specialized form of arthritis called psoriatic arthritis. Eyes In rare cases, psoriasis can cause a red, painful ring around the pupil of the eye in a condition called iritis or anterior uveitis. It has been reported rarely as a presenting symptom of psoriasis and can be diagnosed by an ophthalmologist.