• Psoralen plus ultraviolet A (PUVA): This treatment involves taking a light-sensitizing medication (psoralen) before exposing the affected skin to UVA light. UVA light penetrates deeper into the skin than does UVB light, and psoralen makes the skin more responsive to UVA exposure.
This more aggressive treatment consistently improves skin and is often used for more-severe psoriasis. Short-term side effects might include nausea, headache, burning and itching.
• Excimer laser: With this form of light therapy, a strong UVB light targets only the affected skin. Excimer laser therapy requires fewer sessions than does traditional phototherapy because more-powerful UVB light is used. Side effects might include inflammation and blistering.
Oral or injected medications:
If you have moderate to severe psoriasis, or if other treatments haven't worked, your health care provider may prescribe oral or injected (systemic) drugs.
• Steroids. If you have a few small, persistent psoriasis patches, your health care provider might suggest an injection of triamcinolone right into them.
• Retinoids: Acitretin and other retinoids are pills used to reduce the production of skin cells. Side effects might include dry skin and muscle soreness. These drugs are not recommended when you're pregnant or breastfeeding or if you intend to become pregnant.
Courtesy: Mayo Clinic