Adverse reactions to topical common cosmetics are more common in clinical practice. Common cosmetic adverse reactions include contact dermatitis, hormonal dermatitis, acne, pigment abnormalities, photosensitivity dermatitis, hair and nail damage, etc. The most common is contact dermatitis, which is mainly due to the presence of pigments, fragrances and allergenic preservatives in cosmetics. Therefore, the current medical skincare concept is to not add any coloring or fragrance to skincare products and to require the use of non-allergenic preservatives. However, even without the addition of flavors and colors, each skin care product contains dozens of ingredients, and a few patients may still develop contact dermatitis and worsen their symptoms. The contact dermatitis is divided into irritant contact dermatitis and allergic contact dermatitis. Glucocorticoid-dependent dermatitis, however, generally reverberates with symptoms after discontinuation of topical glucocorticoids (or discontinuation of injectable and oral hormones), but the patient may first think of an allergic reaction to skin care products. Therefore, it is important to distinguish between these three different conditions: 1. Irritant contact dermatitis (1) Occurs immediately after using skin care products. (2) There is a mild tingling and itching sensation, and most patients’ symptoms will gradually subside in about 1 week, and some patients will subside after a few minutes of use, so skin care products can continue to be used. (3) If the symptoms do not subside after 2 weeks of continuous use, it is recommended to stop using this skin care product. (2) Allergic contact dermatitis (1) There may be no obvious adverse reaction at the time of using skin care products, but it occurs after 1-2 days, and the symptoms gradually worsen. (2) Appears obvious itching, burning, and large areas of skin redness, swelling, lesions often occur in the overall part. (3) Skin care products must be stopped immediately. (3) Hormone-dependent dermatitis symptoms rebound (1) Occurs 3-5 days after discontinuing glucocorticoid drugs (or glucocorticoid-containing skin care products). (2) The lesions are dark red, but the patient has unpleasant symptoms. (3) The distribution of lesions is relatively limited, usually mainly on the cheeks.