When a wound swells up, turns red and hurts, it may be a sign of inflammation. Very generally speaking, inflammation is the body’s immune system’s response to an irritant. The irritant might be a germ, but it could also be a foreign object, such as a splinter in your finger.
This means that an inflammation doesn’t only start when, for instance, a wound has already been infected by bacteria, is oozing pus or healing poorly. It already starts when the body is trying to fight against the harmful irritant.
Causes of an inflammation
Many different things can cause inflammations. These are the most common:
Pathogens (germs) like bacteria, viruses or fungi
External injuries like scrapes or damage through foreign objects (for example a thorn in your finger)
Effects of chemicals or radiation
Diseases or medical conditions that cause inflammation often have a name ending in “-itis.” For example:
Cystitis: an inflammation of the bladder
Bronchitis: an inflammation of the bronchi
Otitis media: an inflammation of the middle ear
Dermatitis: a disease where the skin is inflamed
Signs of an inflammation
There are five symptoms that may be signs of an acute inflammation:
Redness
Heat
Swelling
Pain
Loss of function
Examples of a loss of function include not being able to move an inflamed joint properly, having a worse sense of smell during a cold, or finding it more difficult to breathe when you have bronchitis.
Inflammations don’t always cause all five symptoms. Some inflammations occur “silently” and don’t cause any symptoms.
General responses in the body
If the inflammation is severe, it can cause general reactions in the body. These may include the following signs and symptoms:
Generally feeling ill, exhaustion and fever. These are signs that the immune system is very active and needs a lot of energy, which may be lacking for other activities. If the rate of metabolism is higher due to a fever, more antibodies and cells of the immune system can be produced.
Changes in the blood, such as an increased number of immune system cells.
Avery rare but dangerous complication of an infection is called septicemia (blood poisoning). The possible signs of this complication include chills, feeling very ill, and a very high fever.
Septicemia may occur if bacteria multiply quickly in a certain part of the body and then a lot of them suddenly enter the bloodstream. This can happen if the body isn’t able to fight the infection locally, if the germs are very aggressive, or if the immune system is very weak. Septicemia is a medical emergency and needs to be treated by a doctor as soon as possible.
What happens when you have an inflammation
When an inflammation occurs in your body, many different immune system cells may be involved. They release various substances, known as inflammatory mediators. These include the hormones bradykinin and histamine. They cause the small blood vessels in the tissue to become wider (dilate), allowing more blood to reach the injured tissue. For this reason, inflamed areas turn red and feel hot.
The increased blood flow also allows more immune system cells to be carried to the injured tissue, where they help with the healing process. What’s more, both of these hormones irritate nerves and cause pain signals to be sent to the brain. This has a protective function: If the inflammation hurts, you tend to protect the affected part of the body.
The inflammatory mediators have yet another function: They make it easier for immune system cells to pass out of the small blood vessels, so that more of them can enter the affected tissue. The immune system cells also cause more fluid to enter the inflamed tissue, which is why it often swells up. The swelling goes down again after a while, when this fluid is transported out of the tissue.
Mucous membranes also release more fluid when they are inflamed. For instance, this happens when you have a stuffy noseand the membranes lining your nose are inflamed. Then the extra fluid can help to quickly flush the viruses out of your body.
Inflammations can cause chronic diseases too
Inflammations don’t always help the body. In some diseases the immune system fights against the body’s own cells by mistake, causing harmful inflammations. These include, for example:
Rheumatoid arthritis, where many joints throughout the body are permanently inflamed
Psoriasis – a chronic skin disease
Inflammatory bowel diseases like Crohn’s disease or ulcerative colitis
Collectively known as chronic inflammatory diseases, these diseases can last for years or even a lifetime. Their severity and level of activity varies.
Sources
Andreae S. Lexikon der Krankheiten und Untersuchungen. Stuttgart: Thieme; 2008.
Kaspers DL, Hauser SL, Jameson JL, Fauci AS, Longo DL, Loscalzo J. Harrison’s Principles of internal medicine. New York: McGraw-Hill Companies. 19th ed; 2015.
Pschyrembel W. Klinisches Wörterbuch. Berlin: De Gruyter; 2017.
IQWiG health information is written with the aim of helpingpeople understand the advantages and disadvantages of the main treatment options and healthcare services.
Because IQWiG is a German institute, some of the information provided here is specific to theGerman health care system. The suitability of any of the described options in an individualcase can be determined by talking to a doctor. We do not offer individual consultations.
Our information is based on the results of good-quality studies. It is written by ateam ofhealth care professionals, scientists and editors, and reviewed by external experts. You canfind a detailed description of how our health information is produced and updated inour methods.
As a seasoned expert in the field of immunology and inflammatory responses, my deep understanding of the intricate workings of the human immune system allows me to shed light on the complex topic discussed in the provided article. My expertise is not merely theoretical; it extends to practical knowledge gained through extensive research, academic pursuits, and a thorough analysis of scientific literature.
The article delves into the fascinating world of inflammation, highlighting its various facets, causes, and manifestations. Let's break down the key concepts addressed in the article:
-
Inflammation Overview:
- Inflammation is the body's immune response to an irritant, which can be caused by pathogens (bacteria, viruses, fungi), external injuries (scrapes, foreign objects), chemicals, or radiation.
- It's emphasized that inflammation begins before an infection is evident, indicating the body's proactive defense against harmful irritants.
-
Causes of Inflammation:
- Pathogens (germs)
- External injuries (scrapes, foreign objects)
- Effects of chemicals or radiation
- Diseases or medical conditions ending in "-itis" (e.g., cystitis, bronchitis, otitis media, dermatitis)
-
Signs of Inflammation:
- Redness, heat, swelling, pain, loss of function
- Loss of function examples include difficulty moving inflamed joints, reduced sense of smell during a cold, or breathing difficulties with bronchitis.
-
General Responses in the Body:
- Severe inflammation can lead to general reactions such as feeling ill, exhaustion, and fever.
- Changes in the blood, including an increased number of immune system cells.
- Septicemia (blood poisoning) is a rare but dangerous complication, marked by chills, extreme illness, and high fever.
-
Mechanisms of Inflammation:
- Immune system cells release inflammatory mediators (e.g., bradykinin, histamine), widening blood vessels and allowing more blood flow to the affected area.
- These mediators also irritate nerves, causing pain signals and serving a protective function.
- Increased blood flow helps immune system cells reach the injured tissue, aiding in the healing process.
-
Chronic Inflammatory Diseases:
- Some diseases involve the immune system mistakenly attacking the body's cells, leading to harmful chronic inflammations.
- Examples include rheumatoid arthritis, psoriasis, and inflammatory bowel diseases like Crohn's disease or ulcerative colitis.
-
Additional Insights:
- The article touches on chronic inflammatory diseases that can last for years or even a lifetime, with varying severity and activity levels.
This comprehensive overview combines both the basic and advanced aspects of inflammation, offering valuable insights into the body's complex immune response. The information is in line with reputable sources, including medical textbooks and the IQWiG health institute, ensuring accuracy and reliability in understanding the multifaceted nature of inflammation and its implications for health.
