Clinical manifestations The disease is more common in men than in women, especially in young adults. The lump around the anus is mildly painful, or it may feel stinging or swelling pain in the anus, followed by increased pain, increased size of the lump around the anus, redness, swelling, tenderness, hardness, accompanied by different degrees of fever, lethargy, loss of appetite, constipation and other symptoms. Abscesses can be formed locally in about a week, and there can be local fluctuation after abscess formation. If the abscess breaks down by itself or after incision, yellowish-white pus can flow out, after which the pain can be gradually relieved or disappeared and the body temperature drops. Other symptoms may also be relieved. The symptoms vary depending on the location and depth of the abscess. For example, the interstitial abscess above the anal raphe is deep and hidden, with heavy systemic symptoms but light local symptoms, while the interstitial abscess below the anal raphe is shallow, with obvious local redness, swelling and heat pain but light systemic symptoms. 1.Para-anal subcutaneous abscess occurs in the subcutaneous tissue around the anus and is the most common. The abscess is usually small, and the systemic symptoms are not obvious, but the local pain is heavy, mostly persistent or throbbing pain. There is obvious redness, hardness and tenderness in the perianal area. If the abscess has become purulent, there is a fluctuating sensation. Difficulty in urination may occur if the abscess is located on the anterior side. Examination reveals a slightly red raised mass on the anal side with inconspicuous boundaries and obvious tenderness. 2.Sciatorectal interstitial abscess Occurring between the anus and the sciatic tuberosity, located in the sciatorectal interstitial space, the abscess is extensive and deep. Initially, it only feels discomfort or slight pain and soreness in the anus. Systemic symptoms of toxicity are obvious, with high fever, chills, headache, weakness, difficulty in urination and loss of appetite. Subsequently, the local symptoms worsen. Skin swelling, redness and dull pain appear on the anal side of the affected area, and throbbing pain after abscess formation. The pain increases during defecation, coughing, walking, and even sitting and lying down. There are localized hard nodules and obvious pressure pain on palpation. There is pressure pain and fluctuating sensation in the anal canal or rectal wall corresponding to the anorectal hiatus of the patient by anal finger diagnosis. 3.Pelvic rectal interstitial abscess Located above the anal raphe and below the peritoneum. Mostly formed due to abscesses in the sciorectal space, which are not drained by surgery in time and the pus penetrates upward into the anal raphe. It is also formed directly by the spread of inflammation of the anal sinus and anal gland. Because the abscess is deep and hidden, the symptoms of systemic infection are very serious, while the local symptoms in the anus are not obvious. Due to the deep abscess site, it takes longer time to break down by itself. On finger palpation, a bulging mass can be palpated on the rectal wall, with pressure pain and fluctuating sensation. 4.Posterior rectal space abscess Discomfort in defecation is an early symptom. At the initial stage, there is malignant chill and fever, and there is obvious feeling of swelling in the rectum, and the pain in the perineum is dull and can be radiated to the lower limbs. As the lesion continues to develop, the systemic symptoms may worsen, and there is obvious deep pressure pain between the tailbone and the anus. The finger palpation in the anus can be done after the anal canal, below the level of the anal canal rectal ring, and a limited hard nodule or mass can be palpated with fluctuation. 5. Rectal submucosal abscess is located in the submucosal space between the rectal mucosa and the internal sphincter. Initial symptoms often include a feeling of heaviness or fullness in the rectum, and pain is obvious when defecating or walking. Generally, the systemic symptoms are obvious, while there are no obvious local symptoms in the anus, and superficial masses can be palpated under the mucosa with pressure pain and fluctuating sensation during the internal finger examination. 6.Tuberculous perianal abscess often starts slowly, the swelling and pain are light, and the pus is thin or with cheese-like material after ulceration or incision, often accompanied by low fever, night sweats, zygomatic redness, physical wasting and other symptoms.