Psoriasis is an autoimmune disease that causes red, scaly patches on the skin. Sometimes, psoriasis can look like other diseases that share similar characteristics. The National Institute of Arthritis and Musculoskeletal and Skin Diseases estimates that up to 3 percent of the population may suffer from psoriasis. A dermatologist can confirm whether the skin condition is psoriasis or a disease that looks like psoriasis.
Eczema
At first glance, psoriasis and eczema can look like the same skin disease. Sometimes, only a dermatologist can tell the difference between the two conditions. Eczema typically appears on the face, but also affects the arms, elbows and knees. These patches may become red and inflamed and ooze like a blister. The main difference between the two conditions is the symptom of itching: psoriasis causes occasional itching and eczema causes constant itching. Additionally, psoriasis can appear on any part of the body, but eczema occurs in confined areas of the body.
Seborrheic Dermatitis
Seborrheic dermatitis is a disease that affects the oil glands, causing red or pink patches on the face, chest, back and shoulders. Seborrheic dermatitis commonly appears on the sides of the nose, eyebrows, eyelids, and the crevices behind the ears. Although seborrheic dermatitis can look like psoriasis, seborrheic dermatitis causes more peeling and itchiness than psoriasis and appears on the skin where oil glands commonly get clogged, such as the face.
Pityriasis Rosea
Pityriasis rosea is a skin disease that causes large, thick, oval-shaped patches on skin, which typically appear on the arms, thighs, and the body's trunk. The area affected by pityriasis rosea---the body's midsection---is the most telltale sign that the outbreak is not a symptom of psoriasis.
Pityriasis Rubra
Pityriasis rubra pilaris is a skin disease caused by keratinization, where the skin produces more cells than needed. The effect causes thick, inflammed patches on the skin. Pityriasis rubra pilaris causes follicular-based papules, whereas psoriasis appears as a scaly expression on the skin. The American Osteopathic College of Dermatology says that pityriasis rubra pilaris is uncommon in persons over 60 years of age. Psoriasis can develop at any age, affecting infants, children and older adults.
