Immune system

The immune system protects the body from diseases by combating hazardous substances and pathogens. However, this complex system is far from immune to disorders of its own. Both depressed and overactive immune responses can make people ill, for example by causing autoimmune diseases. Inappropriate immune responses can also cause allergies.

The image pictures a young woman’s face covered in multiple red spots.

Acne inversa

Acne inversa (hidradenitis suppurativa) is a chronic inflammatory skin condition. It causes issues such as painful nodules and abscesses. Find out what can be done to help combat it.

A woman sits bent forward on the toilet, holding a roll of toilet paper in her hand.

Crohn’s disease

Crohn’s disease is a chronic disease involving inflammation of sections of the digestive system. Read on to find out what causes it and which treatment options are available.

Psoriasis

Psoriasis is an inflammatory, non-contagious skin condition. It is characterized by reddish, flaky skin that may be itchy.

Neurodermatitis

People with neurodermatitis often get a rash and a nagging itching. This skin condition often occurs in children. Learn more about neurodermatitis and the treatment options.

Nesselsucht: Die nackten Beine eines Menschen sind mit einem Ausschlag überzogen. Der Ausschlag ist leicht rötlich und wirkt geschwollen.

Urticaria

Urticaria (hives) is a skin condition with which itchy wheals or a painful swelling of the hypodermis (angiodema) form. Read more about symptoms, progression, and treatment.

HIV and AIDS

The HIV virus infects immune cells and weakens the immune system. The serious illnesses caused by HIV are called AIDS.

Allergies

An allergy occurs when the immune system has an overly sensitive reaction to a harmless substance such as plant pollen. There are various ways to treat an allergy.

Asthma

Asthma is a chronic disease that causes a narrowing of the airways. An asthma attack makes breathing difficult. Asthma is treated effectively with medication.

Rheumatoid arthritis

Rheumatoid arthritis typically causes chronic inflammation of multiple joints. As a result, the joints can become deformed and stiff over time.

Rosazea: Die Wange einer Frau ist leicht geörtet. In ihrem Auge sind rote Äderchen zu sehen.

Rosacea

Rosacea, a common inflammatory disease of the facial skin, causes redness, pustules, and small visible blood vessels on the face.

Type 1 diabetes

With type 1 diabetes, the pancreas produces very little or no insulin. To supply the body with this essential hormone, people with the disease need daily injections of insulin.

Hay fever

Many children and adults are affected by hay fever in the spring and summer months, when plants grow and bloom. It is caused by an allergic reaction to pollen in the air, affecting the upper airways.

Psoriatic arthritis

Psoriatic arthritis refers to inflammation of the joints as a result of psoriasis. It causes stiff and painful joints.

Rheumatic heart disease

Auslöser der rheumatischen Herzkrankheit sind Streptokokken. Diese Bakterien verursachen akute Atemwegsinfektionen. In response, the immune system creates antibodies that may also attack and damage the heart.

A young girl is feeling ill and is lying on the sofa, being cared for by her grandmother.

Antibody deficiencies

Antibodies play an important role in protecting the body from pathogens. An antibody deficiency weakens the immune system, resulting in frequent infections.

A woman is having her heart listened to.

Acute myocarditis

Acute myocarditis (inflammation of the heart muscle) can be a rare consequence of an infection. There are mild but also life-threatening forms.

Hypothyroidism: woman clutching her throat.

Underactive thyroid

With an underactive thyroid, the thyroid gland does not produce enough hormones. This slows down the metabolism. People affected often feel lethargic, have a low heart rate and constipation.

Herpes labialis: young woman with cold sores on her upper lip.

Oral herpes (cold sores)

With oral herpes, particular herpes viruses cause painful blisters known as cold sores to form. The condition heals on its own in 1 to 2 weeks. No treatment is normally required.

Vitiligo

Vitiligo is a disorder that causes the loss of the brown skin pigment melanin. It usually begins as white skin patches on the face and hands. Read more about its causes and treatment.

Hausstauballergie: Eine Frau wischt Staub und hält sich die Hand ins Gesicht. Ihre Augen sind gerötet.

Dust mite allergy

In dust mite allergies, it isn’t the dust itself that causes the symptoms. Instead, the symptoms such as sneezing are triggered by substances that are mainly found in the dust mites’ feces.

Insect bites: the legs of a young person sitting in a meadow with bites at various points, including some wounds and scratches.

Insect venom allergy

Insect stings or bites usually leave behind nothing more than a small red mark. But someone who has an insect venom allergy will react very severely. It can even be life-threatening.

Contact allergy

A contact allergy can cause severe skin reactions. The symptoms only become noticeable after 1 to 3 days.

Medication allergy

Medication can also have undesired effects. These side effects include allergic reactions.

Food allergy

People with a food allergy usually react to even very small quantities. What are the typical symptoms? How is a food allergy treated?

Oral thrush is caused by a fungus, specifically the various types of Candida fungus.

Oral thrush (oral candidiasis)

If a person's mouth constantly feels furry, it may be caused by oral thrush. It is rarely dangerous, but often unpleasant.

Animal allergy

In an animal allergy it is not the fur that causes a reaction, but proteins that are found in the animal’s saliva, for instance. Avoiding contact with the animal can help, as can taking medication.