There are differences between pityriasis rosea and stage 2 syphilis rash in terms of formation causes, clinical symptoms, treatment methods and so on. 1. Causes: the cause of pityriasis rosea is unknown and may be related to herpes virus infection, immune dysfunction, some drugs, mental state, allergies and other reasons. Stage II syphilis rash is mainly due to syphilis spirochete infection. 2. Clinical symptoms: (1) pityriasis rosea: less in the face and hands and feet, mostly in the trunk and proximal limbs, the rash is rose red, light red or yellowish brown, round or oval, with fine scales attached, the long axis of the rash and the direction of the skin grain is parallel to each other, non-infectious. (2) Stage II syphilis rash: it can cover the mucous membrane and skin of the whole body, the color is red or reddish-brown, manifested as papules, plaques, maculopapular and other lesions; there may also be scabs, desquamation, pustules, ulcers, and ulcers may appear on the mouth, throat and genitals, and it is highly contagious. 3. Treatment: pityriasis rosea can be treated with hydrocortisone ointment and other drugs to reduce swelling and relieve itching. Stage II syphilis is mainly treated with penicillin drugs such as benzylpenicillin. Rose chafing rash and syphilis rash, all need to be under the guidance of a doctor to develop a treatment plan, medication needs to follow the doctor’s orders.