Which of the following factors is the primary etiological factor in psoriasis?

Explanation: Psoriasis is an autoimmune skin disorder where the immune system mistakenly attacks healthy skin cells, leading to the rapid buildup of skin cells and the formation of red, scaly patches on the skin's surface.

Incorrect choices: a. A contagious bacterial skin infection - Psoriasis is not caused by bacteria, and it is not contagious.

c. A fungal infection causing itching and rash - Psoriasis is not caused by a fungus; it is an autoimmune condition.

d. A viral skin condition resulting in fluid-filled blisters - Psoriasis does not result in fluid-filled blisters; it presents as red, scaly patches instead.

Explanation: Psoriasis lesions commonly appear in a symmetrical pattern, affecting similar areas on both sides of the body. For example, if a plaque is present on the right elbow, there is a high likelihood of a corresponding plaque on the left elbow.

Incorrect choices: a. Psoriasis lesions are evenly distributed across the body: Psoriasis lesions are not evenly distributed and tend to cluster in certain areas, such as elbows, knees, scalp, and lower back.

b. Psoriasis lesions are typically limited to the face and neck: While psoriasis can occur on the face and neck, it is more commonly found on extensor surfaces (elbows and knees) and the scalp.

c. Psoriasis lesions are more commonly found on the left side of the body: There is no evidence to support a preference for the left side of the body in psoriasis distribution. The symmetrical pattern is a more characteristic feature.