Most post-injection abscesses can be prevented, and an abscess detected in time is much easier to treat than one that has started. The editors explain the principles of safe injections, how to distinguish between normal soreness and inflammation, which examinations are performed and in which cases emergency help is needed.
Prevention: general principles of safe injections
For people who receive injectable drugs (eg, hormone replacement therapy, vitamin B12, anticoagulants, or insulin for diabetes), abscess prevention is based on the general principles of injection safety formulated by WHO. Their essence is to prevent germs from entering the tissue and not to injure it once more.
- Use only registered drugs from a pharmacy, with intact packaging and within the expiration date.
- Use a new sterile syringe and needle for each injection; never use someone else's equipment.
- Observe hand hygiene and skin care as directed by a healthcare professional.
- Follow the storage instructions for multidose vials. Do not use a product whose appearance has changed unexpectedly or differs from its label; some approved suspensions are normally cloudy.
- Dispose of used needles in a special container.
If the patient injects the drug independently according to the prescription, the doctor or nurse must teach the technique: choosing a place, alternating areas, volume of solution for a specific drug. The editors deliberately do not provide such instructions for anabolic steroids and other means used without medical indications.
For non-medical injections, the most important risk factor — the unknown composition and nonsterility of the drug itself — is completely beyond the control of the user. Therefore, the most effective prevention of abscess in this context is the refusal of such injections.
It is also important to monitor the general condition: uncontrolled diabetes, immunosuppression, and carriage of staphylococcus increase the risk of infections. People with recurrent skin infections should discuss this with their doctor.
How to distinguish a normal reaction from an abscess
Mild soreness after an intramuscular injection is a common phenomenon. The problem is that an early abscess at the beginning also looks like "just hurts". The editors suggest focusing on the dynamics.
| Sign | Normal reaction | Possible abscess or infection |
|---|---|---|
| Pain | Weakens in 1-3 days | Increases, becomes pulsating |
| Redness | Minimal or absent | Expands, borders are blurred |
| Swelling, firmness | Small, decreasing | Increases, fluctuation appears |
| Body temperature | Normal | Increased, chills |
| General condition | Not changed | Weakness, malaise |
An important signal is pain that seems more severe than can be explained by the appearance of the skin. Such a discrepancy is characteristic of deep infections, in particular necrotizing fasciitis, and requires immediate examination by a surgeon.
It is dangerous to “wait until it breaks”, apply heating compresses or squeeze out the contents on your own: it can contribute to the spread of infection into deep tissues and the bloodstream.
Diagnosis
The diagnosis of an abscess is usually made by a surgeon during an examination. The doctor assesses the size, boundaries and tenderness of the lump, the presence of fluctuance, the condition of nearby tissues and lymph nodes, and measures the temperature.
Ultrasound examination of soft tissues is a key instrumental method. It shows whether there is a cavity with liquid in the tissue, its size, depth and relation to vessels. Ultrasound helps to distinguish an abscess from a phlegmon, hematoma, or oil granuloma and to plan drainage.
Blood tests (complete blood count with differential, C-reactive protein) reflect the severity of inflammation. In case of fever, signs of sepsis or suspected spread of infection, a blood culture is taken. After opening, the contents of the abscess are sent for bacteriological examination to determine the causative agent and its sensitivity to antibiotics, in particular to detect MRSA.
In complex cases — with a deep location, suspected bone or joint damage, necrotizing infection — CT or MRI is used. For people who self-administered drugs, the doctor can also offer an examination for HIV and viral hepatitis.
Treatment and when to consult a doctor
According to the guidelines of the Infectious Diseases Society of America (IDSA), the mainstay of treatment for a formed abscess is surgical opening and drainage. Antibiotics are prescribed depending on the size, condition of the patient, signs of systemic infection and concomitant diseases. Both decisions are made by the doctor.
Sterile abscesses and oil granulomas also often require surgical treatment, sometimes removal of altered tissue. Antibiotics are ineffective in this case, so accurate diagnosis is very important.
When to seek care
- Immediately: fever above 38 °C with chills, rapidly spreading redness, severe pain, darkened skin or blisters, confusion or a rapid heartbeat. Seek emergency assessment; use your local emergency number if needed.
- The same day: increasing pain, swelling or redness, or a fluid-like swelling at the injection site.
- Arrange a medical appointment: a firm lump persisting for weeks or repeated reactions at injection sites.
During the examination, it is important to name the drug and its source, the date of injection and other possible risks. This information helps the doctor choose the right tactics, including taking into account the risk of MRSA or a sterile process.
Editorial conclusions
Prevention of post-injection abscess is based on the use of only registered drugs, sterile disposable equipment and techniques taught by a healthcare professional. For non-medical injections, the main risk factor — a non-sterile drug — is not controlled, so the best prevention is to avoid them.
Pain, swelling, and redness that develop after the injection are signs of a possible abscess. Diagnosis is confirmed by examination, ultrasound and tests, and treatment often requires surgical drainage.
Fever, rapidly spreading redness, and severe pain are indications for emergency care.
We also recommend our materials on the causes of abscesses after injections, on POME and on the control of infectious risks during injection therapy.
References
- Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):e10âe52.
- World Health Organization. WHO best practices for injections and related procedures toolkit. Geneva: WHO; 2010.
- Hope VD, McVeigh J, Marongiu A, et al. Injection site infections and injuries in men who inject image- and performance-enhancing drugs: prevalence, risks factors, and healthcare seeking. Epidemiol Infect. 2015.
- Hope VD, McVeigh J, Marongiu A, et al. Prevalence of, and risk factors for, HIV, hepatitis B and C infections among men who inject image and performance enhancing drugs: a cross-sectional study. BMJ Open. 2013;3(9):e003207.
- Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341â375.
