Both allergies and autoimmune diseases are caused by impaired control. In the case of allergies, our body overreacts to foreign substances that are actually not harmful; in the case of autoimmune diseases, even the body's own cells and structures are attacked by its own immune cells.
Allergies – overreaction of the immune system
An allergy or a hypersensitivity reaction is an acquired, specific reaction to non-harmful substances, known as allergens. Our immune system reacts to repeated contact with this allergen as if it were a pathogen and tries to fight it off and eliminate it.
Nowadays, we know of more than 20,000 different allergy triggers. It often takes a long time to find out what the body is hypersensitive to, as allergens can trigger reactions in a variety of ways.
Allergy triggers:
In the case of a food allergy, certain foods such as nuts, milk, cereals or shellfish cannot be tolerated.
In the case of contact allergy, as the name suggests, (skin) contact with certain substances is enough to cause a reaction. These include, for example, metals such as nickel, fragrances, cosmetics and latex.
However, medications or the accompanying substances in injections can also be triggers in the case of a drug allergy, as can insect bites or stings, for example by bees, wasps or mosquitoes.
The inhaled allergens are particularly difficult to avoid, as they enter the body via the air we breathe. The list of these allergens is long and ranges from pollen, spores and animal hair to house dust. Inhalant allergies are by far the most common allergy triggers, led by hay fever which is triggered by pollen.
Symptoms of allergies:
Not only the allergy triggers, but also the symptoms have a wide range and vary greatly from person to person. The symptoms of an allergy can affect the whole body and occur both immediately and with a delay.
- Allergic reactions of the respiratory tract: runny nose, sneezing, shortness of breath
- Allergic reactions of the eyes: red, itchy, watery eyes
- Allergic reaction of the gastrointestinal tract: diarrhoea, flatulence, feeling full, vomiting and inflammation of the mucous membranes
- Allergic reaction of the skin: redness, itching, swelling, weeping blisters, hives, crusty or scaly skin
In principle, it is difficult to predict how an allergy will develop over time. But allergies often become even more widespread at younger ages.
However, with advancing age, this can reverse, as the normal decline in immune function causes our immune system’s reactions to decline and, in the best case, even stops reacting completely to allergens.
Autoimmune diseases – immune system fights against the body
In short, in autoimmune diseases, the body's own tissue is attacked by certain cells and antibodies of the immune system. Normally, misdirected defence cells are sorted out by your own body, so that only cells that do not work against your own antigens are present. This normal process is called immune tolerance.
In autoimmune diseases, on the other hand, immune tolerance is lost, as a result of which cells or antibodies target their own tissue. Most autoimmune diseases are detected by autoantibodies in the blood
It is not certain why these malfunctions of the immune system occur, but an interplay of several factors is suspected. Genetic predisposition, vaccinations, toxins or previous infections with bacteria or viruses (e.g. the Epstein-Barr virus) may play a role. The fact is, however, that 90% of autoimmune diseases occur in women, as the female hormones are more likely to promote inflammation. Today, around 60 different autoimmune diseases are known.
Examples of autoimmune diseases:
- Multiple sclerosis (MS) is an inflammatory disease of the central nervous system. Misdirected cells attack the protective insulating layer of the nerve cells.
- In type 1 diabetes, the defences in the pancreas destroy the beta cells, which are needed for the production of the hormone insulin.
- In rheumatoid arthritis, the tissue in the inner membranes of the joints is not considered to belong to the body. This erroneous immune reaction leads to inflammation, so that the inner membranes of the joints proliferate and destroy the joint-protective cartilage.
- In psoriasis, immune cells classify the body's own skin cells as foreign bodies, resulting in an inflammatory reaction of the skin.
- Systemic lupus erythematosus (SLE) is an autoimmune disease of the connective tissue, which can affect all organs (systemic). It leads to inflammation of vessels, muscles, joints and various organs. Often the skin is affected and a symmetrical, butterfly-shaped reddening of the skin can appear on the face.
Since the causes of autoimmune diseases are not certain, it is usually only possible to treat the respective symptoms.
In severe cases, immunosuppressants are prescribed to suppress the body’s normal defence function and thus stop the misdirected process of the immune system.
Unfortunately, we can see that the number of both allergies and autoimmune diseases is constantly increasing. One possible explanation, known as the “hygiene theory”, suspects excessive hygiene in childhood as the cause.
Due to too few contacts with a wide variety of microorganisms, we deprive our immune system of the opportunity to learn. But also an unhealthy lifestyle with stress, regular alcohol or nicotine consumption, too little exercise and insufficient nutrient intake weakens our immune system.