The red, swollen, and hardened skin on the chin is considered to be caused by acne, boils, epidermal cysts, and other diseases.
1. Acne: The cause of acne is related to excessive sebum secretion and blockage of the sebaceous gland ducts of hair follicles. It occurs on the face, with lesions characterized by pimples, papules and pustules, while some patients have lesions that appear as nodules, which are hard and painful lumps.
2. Boil: Boil is an inflammation of the hair follicle and its deep surrounding tissues, usually caused by Staphylococcus aureus infection. It presents as one or more red, hemispherical painful nodules and can occur anywhere.
3. Epidermoid cysts: Epidermoid cysts are a kind of cysts containing keratin in the dermis, which are common in the face and upper trunk, and the etiology is related to embryonic odor and skin injury. It manifests as an isolated intradermal or subcutaneous nodule that is moderately hard, and if it is secondary to an infection, it can become red, swollen, painful, and other discomforts.
There are more causes of red, swollen and hard skin growths on the chin, so it is recommended to seek medical examination and detailed counseling.