Abscess: Causes and anatomical pathology findings

1. What is an abscess?

An abscess is a common infectious condition characterized by the formation of painful and uncomfortable pus-filled pockets due to infection. It is the body's natural response to contain an infection and prevent the spread of bacteria [3].

2. What are the different types of abscesses?

Abscesses can occur anywhere in the body and are classified according to their duration and characteristics:

• Acute abscess: Usually develops rapidly, with prominent inflammatory symptoms such as swelling, warmth, redness, and pain, and typically resolves within six weeks [1].
• Chronic abscess: Persists for more than six weeks, may be surrounded by a thick fibrous capsule, and tends to present with fewer acute symptoms [1].
• Aseptic abscess: A collection of fluid without bacteria, commonly found in patients with inflammatory bowel disease and potentially representing the first sign of the disease [2]. This type of abscess does not respond to antibiotics but responds well to immunosuppressive therapy [2].

3. Why do abscesses develop?

Causes and risk factors

Abscesses commonly develop due to several main causes:

• Bacterial infections: This is the most common cause, often involving anaerobic and aerobic bacteria or polymicrobial infections [1]. Bacteria can enter the body through open wounds, blocked hair follicles, or other sites of infection within the body [6].
• Obstruction of ducts: Blockages in the body's natural ducts, such as sweat glands, sebaceous glands, bile ducts, and urinary tract, can create conditions that allow bacteria to multiply and abscesses to form [1].
• Trauma or surgery: Injuries or surgical procedures may introduce bacteria deep into tissues, leading to infection and abscess formation [2]. For example, approximately 70% of intra-abdominal abscesses occur as a consequence of surgery [2].
• Weakened immune system: People with weakened immune systems due to conditions such as diabetes or HIV/AIDS, or those taking immunosuppressive medications, are at higher risk of developing abscesses and often have a poorer prognosis [1].

Signs and symptoms

Symptoms of an abscess vary depending on its location and the severity of the infection, but commonly include:

• Local symptoms: Classic signs of inflammation, including pain, swelling, warmth, and redness in the affected area. Pus may drain if the abscess ruptures [1].
• Systemic symptoms: Fever, chills, fatigue, loss of appetite, and weight loss [1].
• Location-specific symptoms:
  • Lung abscess: Coughing up purulent sputum, chest pain, and shortness of breath [1].
  • Brain abscess: Headache, altered mental status, and weakness or paralysis [6].
  • Intra-abdominal abscess: Abdominal pain, nausea, and vomiting [2].
  • Liver abscess: Right upper quadrant pain, fever, and jaundice [2].
  • Periodontal (dental) abscess: Severe toothache, swollen gums, and possible spread of swelling to the face [5].

4. Diagnosis of abscesses and the role of anatomical pathology

To diagnose an abscess, doctors combine several methods, including clinical examination, laboratory tests, and diagnostic imaging. However, the final diagnosis may sometimes depend on the anatomical pathologist. Anatomical pathology is an important step, particularly when the precise nature of a lesion needs to be established, other conditions such as tumors need to be excluded, or the causative pathogen needs to be identified. Specimens of pus or tissue are obtained through aspiration or biopsy and sent to the laboratory for microscopic examination and microbial culture [2].

5. What should you understand about anatomical pathology findings in abscesses?

• Determining the nature of the lesion: Distinguishing an abscess from tumors or noninfectious cysts [3].
• Assessing the degree of inflammation and necrosis: Determining the severity of the inflammatory response and the extent of tissue destruction [1].
• Identifying potential pathogens: In some cases, bacteria, fungi, or parasites may be visible under the microscope, helping guide the selection of appropriate antibiotics, antifungal medications, or antiparasitic drugs [1].

Common terms in anatomical pathology reports and their meanings

When reading an anatomical pathology report related to an abscess, you may encounter the following terms:

• Acute inflammation: Indicates an ongoing inflammatory response, typically characterized by the presence of polymorphonuclear neutrophils [1].
• Liquefactive necrosis: A process in which tissue is destroyed and converted into a liquid-like substance, forming pus. This is a characteristic feature of abscesses [1].
• Pus collection: Confirms the presence of pus, which consists of dead cells, white blood cells, and bacteria [3].
• Fibrous capsule or pyogenic membrane: A layer of fibrous tissue surrounding an abscess, formed to contain the infection [1]. The presence of a thick fibrous capsule may indicate a chronic abscess and influence treatment decisions, which may often involve surgery [1].
• Inflammatory cells:
  • Neutrophils: Predominate in acute inflammation and are a major component of pus [1].
  • Macrophages: Participate in clearing dead cells and bacteria.
  • Lymphocytes and plasma cells: Tend to be more abundant in chronic abscesses.
• Microorganisms: The report may document the presence of bacteria, fungi, or parasites if they are identified [1].
• Granuloma: In some cases of chronic abscesses or infections caused by certain pathogens, such as tuberculosis or fungi, granulomatous structures may form [2].

6. Treatment and prevention of abscesses

Main treatment methods

Abscess treatment often involves a combination of approaches:

• Antibiotic therapy: Broad-spectrum antibiotics are often started immediately and subsequently adjusted according to culture and antimicrobial susceptibility testing results to target the causative bacteria [1].
• Pus drainage: This is a fundamental principle of abscess treatment. Pus must be drained through image-guided aspiration using ultrasound or CT, or through the placement of a drainage tube [2].
• Surgical intervention: Surgery may be indicated when drainage is ineffective, the abscess is large or complex, or complications such as abscess rupture occur [2].

Prevention and when to see a doctor

• Prevention:
  • Good personal hygiene: Maintain skin and oral hygiene and care for wounds properly to prevent bacteria from entering the body [5].
  • Management of underlying conditions: For people with conditions such as diabetes, good blood glucose control helps reduce the risk of infection and abscess formation [1].
  • Early treatment of infections: Even minor infections should not be overlooked. Prompt treatment is necessary to prevent complications, including abscess formation [1].
• When to see a doctor:
  • Seek immediate medical attention if you experience any of the following: persistent high fever, severe or spreading pain, rapidly increasing redness and swelling, signs of pus drainage, difficulty breathing, or altered mental status [1].

7. Frequently asked questions (FAQ)

• Can an abscess resolve on its own? Abscesses rarely resolve completely without intervention. Although the body can contain an infection by forming a surrounding capsule, drainage and antibiotics are often necessary to eliminate pus and bacteria effectively [3].
• Can abscesses recur? Yes. Abscesses may recur, particularly if the underlying cause is not treated adequately or if the patient has risk factors such as a weakened immune system or poor hygiene [4].
• How should I care for an abscess at home after treatment? Follow your doctor's instructions regarding medications, including antibiotics and pain relievers, wound care, including dressing changes and keeping the area clean, and monitoring for signs of recurrent infection [2].
• Does diet affect abscesses? A balanced, nutrient-rich diet containing adequate vitamins supports immune function and wound healing. However, there is no evidence that a specific diet directly treats or causes abscesses [2].
• When should I go to the hospital immediately if I have an abscess? Seek immediate medical attention if you have a persistent high fever, severe pain that does not improve, rapidly spreading swelling, signs of systemic infection such as fatigue or dizziness, or an abscess in a high-risk location such as the face, neck, or near major joints [1].

8. References

• [1] Sabbula, B. R., Rammohan, G., Sharma, S., & Akella, J. (2024). Lung Abscess. StatPearls - NCBI Bookshelf.
• [2] Mehta, N. Y., Marietta, M., & Copelin II, E. L. (2025). Intraabominal Abscesses. StatPearls - NCBI Bookshelf.
• [3] Schein, M. (2001). Management of intra-abdominal abscesses. Surgical Treatment: Evidence-Based and Problem-Oriented.
• [4] Conner, J. N., Eren, S., & Tuma, F. (2023). Perianal Abscess. StatPearls - NCBI Bookshelf.
• [5] Sanders, J. L., & Houck, R. C. (2023). Dental Abscess. StatPearls - NCBI Bookshelf.
• [6] Hall, W. A., & Mesfin, F. B. (2024). Brain Abscess. StatPearls - NCBI Bookshelf.

The information above is for reference purposes only and is not intended as medical advice. Please contact your doctor for detailed medical consultation.