Allergic dermatitis and rosacea are mainly distinguished from each other in terms of etiology, clinical symptoms, and treatments. 1. Different etiology: atopic dermatitis is mainly caused by skin allergic reactions when the skin comes into contact with external substances, or the use of cosmetics and skin care products, or the consumption of certain foods and medicines; the pathogenesis of rosacea is unclear, and it may be a chronic inflammatory skin disease caused by abnormal skin immune vasoconstriction induced by a number of factors on the basis of a genetic background. 2. Different clinical symptoms: atopic dermatitis causes diffuse erythema, or red spots and papules of rice to bean size, accompanied by itching, etc.; rosacea mainly manifests as symmetrical erythema on the nose, cheeks, and forehead, and persistent redness, accompanied by dryness, burning, or tingling of the skin after high ambient temperatures, spicy foods, exercise, or bathing. 3. Different treatments: atopic dermatitis can be treated with glucocorticoid drugs such as hydrocortisone ointment and dexamethasone ointment, and antihistamine drugs such as loratadine and cetirizine orally; rosacea can be treated with medications such as clindamycin ointment, benzoyl peroxide gel, azelaic acid ointment, and minocycline, isotretinoin, and so on, orally. If you have atopic dermatitis or rosacea, you should go to the hospital in time for examination and follow the doctor’s instructions for standardized treatment, and you should not abuse the drugs by yourself.