Hello, Dry patch on the skin of neck and chest are usually due to dry skin and vitamin D deficiency, you should get appropriate exposure to sun. You should avoid excessive exposure though. Lack of adequate vitamin B12 also causes skin problems, include food rich in vitamin B12 in your diet or take supplements. Other medical conditions that may cause similar symptoms are ring worms, bacterial infections, allergies, dermatitis, psoriasis, eczema, etc. You are suggested to take care of your hygiene. Wear cotton clothes, avoid swimming for a couple of days. If sexually active avoid sex while your are getting treated. You should apply calamine lotion or aloe vera based moisturizer after bath, never leave the skin dry. You can take a course of anti-fungals (Fluconazole) orally and apply Clotrimazole ointment in the area affected locally. If it is infection caused with tinea cruris it will get healed. You can also take a course of non sedating antihistamines orally to get rid of symptoms caused by allergy. However, you are suggested to get clinically examined by a dermatologist so that skin tests or skin biopsy can be done to detect the pathology so that specific treatment can be given. You may be recommended to get STD tests & few blood tests done. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician