• Assessment of tissue level of resolvin D1 in psoriasis in comparison to its level in healthy controls in order to verify its role in the pathogenesis of psoriasis.

Inclusion Criteria:

• Patients with psoriasis (adults and children above 12years)
• Both sexes.
• New cases or cases not receiving any treatment for at least 3 months ago.

Exclusion Criteria:

• Any contraindication to phototherapy treatment (e.g. Photosensitizing creams or medications, past skin cancer, especially melanoma, etc...)
• Erythrodermic and pustular psoriasis.
• History of autoimmune diseases or other systemic diseases (e.g. Alzheimer's disease, fibromyalgia, cystic fibrosis)