Subcutaneous fistula, also known as dermal fistula, is a common term for anal fistula, which is mainly characterized by pain, redness, swelling and itching in the anal area in the early stage. Subcutaneous fistula is often secondary to perianal diseases, such as perianal abscess, sinusitis, etc., early manifestations of perianal disease symptoms. Such as perianal abscess secondary to subcutaneous fistula, early manifestations of redness and swelling of the anus, increased skin temperature, localized pain, obvious and localized fluctuating sensation when pressed, and pus and fecal outflow when the skin is broken. Sinusitis secondary to subcutaneous fistula mainly manifested as perianal itching and fecal discharge incomplete feeling, subcutaneous fistula early treatment effect is good, fast recovery, less recurrence. When you find pain, redness, swelling and itching in the anus, you need to consult a doctor in time to avoid delaying your condition.