Late nights out: “Sleep deprivation causes stress, which can aggravate all skin conditions, including acne, eczema, and psoriasis,” says Karyn Grossman, a dermatologist who practices in Santa Monica, Calif., and New York City.

Late nights out: “Sleep deprivation causes stress, which can aggravate all skin conditions, including acne, eczema, and psoriasis,” says Karyn Grossman, a dermatologist who practices in Santa Monica, Calif., and New York City.