Final answer:
The term describing milky-white patches on the skin is vitiligo. It involves depigmentation of the skin due to the immune system destroying melanocytes, unlike psoriasis, eczema, or rosacea which show different symptoms.
Step-by-step explanation:
The term that describes the milky-white patches on the skin is vitiligo. Vitiligo is characterized by the loss of pigmentation in the skin which results in lighter colored patches. These distinct patches are more noticeable on darker skin and are due to the body's immune system attacking and destroying the melanocytes, the cells responsible for producing melanin, which gives skin its color.
Unlike psoriasis, which causes itchy or sore patches of thick, red skin with silvery scales, or eczema, which is a red, flaky rash caused by an allergic reaction, vitiligo is specifically known for these patches of depigmentation. Rosacea, another skin condition, typically manifests as redness on the face rather than milky-white patches.