Itchy skin on the chest may be caused by ringworm, contact dermatitis, eczema and other diseases. 1. Tinea corporis: Tinea corporis is a superficial cutaneous fungal infection caused by pathogenic fungi parasitizing the smooth skin of the human body. The fungus produces pinhead-sized herpes or mounds of herpes at the invasion site, followed by the points as the center, expanding along the epidermal stratum corneum in all directions to form a ring-shaped damage, with the edge of the reddish mounds, herpes, scales composed of slightly higher than the skin, with clear boundaries and itchy sensation. 2. Contact dermatitis: animal toxins, plant stems and leaves flowers, chemical agents and other irritants may induce contact dermatitis. Patients will appear itching, papules, erythema and other symptoms, serious patients may also appear oozing, crusting, flaking and so on. If it occurs in the chest, it may be manifested as itchy skin on the chest. 3. Eczema: Eczema is caused by heredity, immune system abnormalities, changes in sex hormone levels, endocrine disorders and other factors. Patients will show itching, burning sensation, corn size pimples, redness and swelling, etc. If the affected area is infected, it may also show pustules, pus crusts and fever. Patients may experience itchy skin on the chest. There are more causes of itchy skin on the chest, it is recommended to go to the regular hospital, under the guidance of the doctor, to carry out relevant examinations to identify the cause of the disease.