**Core Concept:** Psoriasis is a chronic inflammatory skin disorder characterized by the overproduction of skin cells, leading to the formation of red, scaly, and itchy plaques. Multiple psoriatic lesions on hands are often treated with topical corticosteroids, which help to reduce inflammation and suppress the abnormal keratinocyte proliferation.

**Why the Correct Answer is Right:** In the case of multiple psoriatic lesions on hands, the treatment of choice is topical corticosteroids (Option C). Corticosteroids are potent anti-inflammatory agents that suppress the abnormal keratinocyte proliferation seen in psoriasis. They work by inhibiting the release of inflammatory mediators, reducing vascular permeability, and suppressing the production of cytokines involved in the pathogenesis of psoriasis.

**Why Each Wrong Option is Incorrect:**
A. Systemic retinoids (e.g., acitretin) are used for severe and recalcitrant psoriasis, not localized lesions on hands.
B. Topical calcipotriol is a vitamin D analog with anti-inflammatory and antiproliferative effects, but it is not as potent as corticosteroids for treating psoriasis.
D. Phototherapy, such as UVB or psoralen plus ultraviolet A (PUVA), is a treatment option for psoriasis; however, it is less effective for localized lesions on hands compared to systemic corticosteroids and calcipotriol.

**Clinical Pearl:** While topical corticosteroids are effective for treating localized psoriasis lesions, systemic retinoids like acitretin are essential for severe and recalcitrant cases. Additionally, phototherapy is not as effective as topical corticosteroids and calcipotriol for localized lesions on hands.