Final answer:
Psoriasis is a chronic autoimmune disease that presents with a pigmented scaly rash on the face, neck, and back of hands. It is triggered by sunlight exposure and can cause diarrhea, irritability, and a depressed mood. Treatment involves medications to reduce inflammation and manage symptoms.
Step-by-step explanation:
The condition that presents with a pigmented scaly rash on the face, neck, and back of hands that increases with sunlight exposure, diarrhea, and irritability/depressed mood is psoriasis. Psoriasis is a chronic autoimmune disease that affects the skin, causing red, thickened patches with silvery scales. This condition is often triggered by exposure to sunlight, and the symptoms can worsen during periods of increased sun exposure.
Psoriasis is caused by an abnormal immune response, where the immune system mistakenly attacks healthy skin cells. This results in the rapid production of new skin cells, leading to the characteristic scaly rash. In addition to the skin symptoms, some individuals with psoriasis may also experience joint inflammation, known as psoriatic arthritis.
Treatment for psoriasis typically involves medications to reduce inflammation and manage symptoms, such as topical corticosteroids, phototherapy, and systemic medications. It is important to avoid triggers, including exposure to sunlight without proper protection.