In most cases, diagnosis of psoriasis is fairly straightforward. Your doctor usually can diagnose psoriasis by taking your medical history and examining your skin, scalp and nails.
Tests aren’t usually needed. But one or more of the following tests may be done:
- Biopsy. If it is hard to diagnose the condition by looking at your skin, your doctor may remove a small skin sample and send it to a lab for analysis.
- X-ray. If you have joint pain, X-rays may be taken to look for psoriatic arthritis.
- Blood test. It can help rule out other forms of arthritis.
- Throat culture. If your doctor thinks you may have guttate psoriasis, he or she may want to check for strep throat.
- KOH test. Sometimes this skin test is done to rule out a fungal infection.
Psoriasis treatments can be divided into three main types: topical treatments, light therapy and systemic medications.
Used alone, creams and ointments that you apply to your skin can effectively treat mild to moderate psoriasis. When the disease is more severe, creams are likely to be combined with oral medications or light therapy. Topical psoriasis treatments include:
- Topical corticosteroids. It slows down cell turnonver and given to patients with mild psoriasis.
- Vitamin D analogues. It slows the growth of cells. This Includes Calcipotriene (Dovonex), Calcitriol (Rocaltrol)
- Anthralin. It normalizes DNA activity in the cells. This Includes Anthralin (Dritho-Scalp)
- Topical retinoids. It normalizes DNA activity in the cells and decrease inflammation. This Includes tazarotene (Tazorac, Avage)
- Calcineurin inhibitors. It disrupts the activation of T cells and reduce inflammation. This Includes tacrolimus (Prograf) and pimecrolimus (Elidel)
- Salicylic acid. It promotes sloughing of dead skin cells and reduces scaling.
- Coal tar.
- Moisturizers. This does not heal psoriasis, but it reduces itching and scaling.
Light therapy (phototherapy)
As the name suggests, this psoriasis treatment uses natural or artificial ultraviolet light. The simplest and easiest form of phototherapy involves exposing your skin to controlled amounts of natural sunlight. Other forms of light therapy include the use of artificial ultraviolet A (UVA) or ultraviolet B (UVB) light either alone or in combination with medications.
- Sunlight. This slows skin cell turnover and reduces scaling and inflammation. Brief, daily exposures to small amounts of sunlight may improve psoriasis, but intense sun exposure can worsen symptoms and cause skin damage.
- UVB phototherapy. UVB phototherapy, also called broadband UVB, can be used to treat single patches, widespread psoriasis and psoriasis that resists topical treatments.
- Narrow band UVB therapy. It’s usually administered two or three times a week until the skin improves, then maintenance may require only weekly sessions.
- Goeckerman therapy. Some doctors combine UVB treatment and coal tar treatment, which is known as Goeckerman treatment. The two therapies together are more effective than either alone because coal tar makes skin more receptive to UVB light.
- Photochemotherapy or psoralen plus ultraviolet A (PUVA). Photochemotherapy involves taking a light-sensitizing medication (psoralen) before exposure to UVA light. UVA light penetrates deeper into the skin than does UVB light, and psoralen makes the skin more responsive to UVA exposure.
- Excimer laser. This form of light therapy, used for mild to moderate psoriasis, treats only the involved skin.
Oral or injected medications
If you have severe psoriasis or it’s resistant to other types of treatment, your doctor may prescribe oral or injected drugs.
- Retinoids. Related to vitamin A, this group of drugs may reduce the production of skin cells if you have severe psoriasis that doesn’t respond to other therapies.
- Methotrexate. Taken orally, methotrexate helps psoriasis by decreasing the production of skin cells and suppressing inflammation. It may also slow the progression of psoriatic arthritis in some people.
- Cyclosporine. Cyclosporine suppresses the immune system and is similar to methotrexate in effectiveness. Like other immunosuppressant drugs, cyclosporine increases your risk of infection and other health problems, including cancer.
- Drugs that alter the immune system (biologics). Several immunomodulator drugs are approved for the treatment of moderate to severe psoriasis. They include etanercept (Enbrel), infliximab (Remicade), adalimumab (Humira) and ustekinumab (Stelara). Biologics work by blocking interactions between certain immune system cells and particular inflammatory pathways.
- Other medications. Thioguanine and hydroxyurea (Droxia, Hydrea) are medications that can be used when other drugs can’t be given.
- Experimental medications. Some of the treatments being looked at include A3 adenosine receptor agonists; anti-interleukin-17, anti-interleukin-12/23 and anti-interleukin-17 receptor agents; Janus kinase (JAK) inhibitors; and phosphodiesterase 4 inhibitors.