What condition is characterized by scaly, itchy skin with yellowish crusting, particularly in winter?

Seborrheic dermatitis is characterized by scaly, itchy skin that often features yellowish crusting, particularly noticeable in the winter months when skin tends to be drier. This condition typically affects areas of the body with a high concentration of sebaceous (oil) glands, such as the scalp, face, and upper back. The crusting is a result of the excessive oil and dead skin buildup, leading to the formation of scales.

In winter, the combination of cold air and indoor heating can exacerbate this condition, making it more pronounced. The itchiness associated with seborrheic dermatitis can vary in intensity, and while it can occur in anyone, certain factors such as stress, hormonal changes, and weather can trigger or worsen episodes.

Other conditions like psoriasis, atopic dermatitis, and contact dermatitis do have distinct features. For instance, psoriasis usually presents with thick, silvery scales and is often more chronic, while atopic dermatitis typically has a more pronounced association with allergy and can result in oozing lesions. Contact dermatitis is primarily an allergic reaction that occurs in response to irritants or allergens, resulting in localized inflammation rather than widespread yellowish crusting.