Hello,
Causes of such an anal rash include moisture(due to sweating or frequent washing), the abrasion caused by clothing,the pressure of sitting,chemical irritants like laundry soaps, colognes and scented toilet paper,certain food irritants,medicines like some antibiotics and laxatives,infections like STD’s and pinworms,anal abrasions and fissures and skin problems such as psoriasis, seborrhea and eczema. Sometimes hemorrhoids will start off as red rash and anal itching.
Treatment of anal itching depends on the cause of the problem.So pls get an examination done by a dermatologist to confirm the diagnosis.Till that time,try an over-the-counter (OTC) cream or ointment containing hydrocortisone (Cortaid, Preparation H),but it is to be applied sparingly to the affected area. A protective ointment that contains zinc oxide (Desitin, Balmex) also may help. If your symptoms are worse at night, pls take an antihistamine like benadryl to reduce itching until topical treatments take effect.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.
if you have cats, it could be ring worm