What skin condition can manifest as patches on the scalp, elbows, and knees?

Psoriasis is a chronic skin condition characterized by the rapid proliferation of skin cells, leading to the formation of thick, scaly patches. These patches typically appear on areas of the body such as the scalp, elbows, and knees, which are common sites for this condition. The skin undergoes a cycle of excessive cell turnover, causing the classic silvery-white scales on a red base. The exact cause of psoriasis is thought to be related to an immune system malfunction, but environmental triggers can also play a role in flare-ups.

In contrast, conditions like acne primarily affect the face and upper body, presenting differently with clogged pores, inflammation, and pustules. Hyperpigmentation involves darkening of the skin due to various factors, but it does not cause patches or scaling akin to what is seen with psoriasis. Therefore, when considering the characteristic patches that appear on the scalp, elbows, and knees, psoriasis is the condition that accurately fits this description.