Rash: What are the causes of rashes (even inflamed, red and itchy rashes)?

The rash can be found on the skin on the surface of the body, but also, for example, on the internal mucous membranes. Sometimes the rash appears only sporadically. However, there are also cases when it appears in larger quantities.

If the rash appears on the skin, it is technically called an exanthema. If it is on the mucous membranes, it is an enanthema. Rashes can appear locally on a specific part of the body, but also all over the body, globally. The shape can vary from a fine spot to a protruding rash.

If the rashes occur in large numbers, they may occur in different shapes or even irregularly in a particular area. The development of a rash also has a definite course.

Later on, it may develop into a harmless flake, for example, but also into a crack, a boil or a larger ulcer. An ulcer may leave an unpleasant scar on the skin.

Most rashes are localised and are an allergic or immune reaction, for example to skin contact with a substance or an insect bite.

If the rash is accompanied by redness, there is an inflammatory process going on in the surrounding area and it may be a skin infection. It may also be a toxic reaction to medication or external stimuli or an allergic reaction of the immune system to an allergen.

If the rash is accompanied by fever or fever, it may be infectious. Many skin diseases, sexually transmitted diseases and other diseases are accompanied by a local rash or multiple rashes all over the body.

Most often, the rash is a symptom of skin diseases. This includes, for example, psoriasis or psoriasis. It is manifested by the appearance of rashes and scales on the skin.

Various dermatitis caused by fungal infections, also in atopic eczema a rash on the skin can be observed.

Minor skin rashes and acne

There are common non-serious rashes where the pores are blocked by dirt. They first appear as a hard red rash, later with a purulent deposit and local swelling. It is painful to the touch.

These classic rashes can appear most often on the face, nose, ear and neck. Rashes on the back are common, especially in the form of acne.

Acne (also acne vulgaris) is the most common chronic skin disease. It occurs especially in adolescence. It manifests itself as a rash in the form of boils. It is caused by inflammation of the sebaceous glands and subsequent closure.

When the sebaceous glands become blocked, sebaceous rashes, cysts, also form. Professionally, this type of sebaceous cyst is called an atheroma. It can subsequently become inflamed, swollen, red and painful to the touch.

In the case of an inflamed hair bed, the rash can be in the armpits, between the eyebrows, but also on the nose, chest, thighs, buttocks. Virtually any hair bed or sweat gland can become inflamed, especially as a result of a blockage.

Allergic reaction

Allergic reaction is an exaggerated reaction of the immune system to an allergen, i.e. a substance that normally does not harm a person.

Anaphylactic shock is also very dangerous in the context of allergy. It is a life-threatening condition where the body's immune response is very extensive and disproportionate.

Swelling of the face and mucous membranes of the airways is a frequent accompaniment. This causes narrowing of the airways and difficulty breathing, in the worst cases even blockage and suffocation.

Infectious diseases

Several other infectious diseases are known to cause a greater incidence of rash. Locally, a rash appears especially in various infectious diseases.

Shingles can be caused by the herpes virus. Chickenpox is similar. Both diseases are caused by the varicella zoster virus, which is one of the so-called herpes viruses.

The disease is characterised by a rash, fever and itchy skin. It is spread through the air and by direct contact with an infected person.

Chickenpox breaks out after the first contact with the varicella zoster virus, as a primoinfection. The virus is never completely eliminated from the body. Subsequently, after the virus is cured and suppressed, it hides in the nerve ganglia. These are small nodules of nerve tissue in the human body.

When the immunity is weakened, with excessive stress or due to other diseases, the varicella zoster virus reactivates and manifests itself as shingles.

Interesting information can also be found in the following articles:
Herpes
Chickenpox
Measles

A rash is also typical of measles. Measles is another typical childhood disease. It mainly affects children around the age of 5. It is a highly contagious infection that presents with fever, conjunctivitis, cough and rashes all over the body.

Another example is rubella. It is a typical childhood disease of infectious origin. It is transmitted by the rubella virus.

Rubella, or erysipelas (erysipelas, erysipelas), is a disease caused by Streptococcus pyogenes. It produces a circumscribed phlegmonous lesion.

At first, taut, painful and shiny skin is present. Later, rashes, blisters and, in the worst cases, foci with necrotic (dead) tissue are formed.

It is most common on the lower limbs (80%) and less common on the face (20%). In addition to rashes and swelling, pain, fever, headache, nausea, vomiting and swollen local nodes are present.

Scarlet fever is also manifested by rashes. The rash in this case is called scarlet exanthema. Its causative agent is the bacterium Streptococcus pyogenes. The disease is accompanied by fever and also sore throat.

But the rash can also occur, for example, in meningitis. The bacteria that cause meningitis enter the bloodstream and from there enter the body. Smaller blue spots are also evident.

In some cases, a rash may also appear in infectious mononucleosis. The viral disease is caused by the EB virus, which is one of the herpes viruses. However, the more common symptom is very severe fatigue and enlargement of the lymph nodes in the neck.

Another example of an infectious disease is tuberculosis of the skin. It has several types and manifestations. But the main skin symptoms include:

• rash
• nodules
• skin defects
• warts
• purulent pustules

Fortunately, the incidence of this form of the disease is very low. It is caused by the penetration of Mycobacterium tuberculosis into the skin. It enters the skin both from the outside and from the inside through the blood or lymphatic system.

Scabies is a disease caused by the mite Sarcoptes scabiei, which lives in the skin and creates small passages in the skin. It manifests itself as itching, rashes, later red rashes and, as a result of bacterial infection, purulent rashes.

It is most often found between the fingers, on the wrists, abdomen, ankles, but also on the genitals in men and in the crotch. In women, rashes on the breasts. In children it occurs on the face, in newborns all over the body.

It is transmitted by contact, through bed linen, but also through sexual intercourse. Therefore, personal hygiene is important, as well as sufficient care of linen in hostels.

Sexually transmitted diseases

Several sexually transmitted diseases are characterised by a rash. One example is syphilis (also known as lues), which is caused by the bacterium Treponema pallidum.

It is a sexually transmitted disease that is transmitted by any bodily fluid. Mother-to-child transmission also occurs.

In the first stage, up to three weeks, syphilitic rashes appear on the body with a red or reddish-pink colour and clear borders. They rise to the surface. Hair loss is not uncommon.

Later on, a hard ulcer appears, like a hard rash. After the obvious symptoms, a symptomless phase sets in. After years, the lues moves into the final stage. This most often affects the central nervous system. But also the heart, large vessels, bones.

The late stage most often leads to mental disorders. Their main cause is brain damage. The worst late-stage complication of the disease is death.

Soft ulcer is also a sexually transmitted disease. It is caused by Haemophilus ducrey.

Local nodes are also affected, in the groin. Less commonly, a rash may appear on other parts of the body, especially the lip, fingers or tonsils.

Genital herpes or herpes is highly infectious. In addition to the manifestations of the herpes virus on the lips, genital diseases are transmitted during sexual practices.

Here, it causes skin manifestations such as rashes, blisters and sores. In men, the rash occurs in the groin, i.e. on the penis, but also in the urethra, which causes painful urination and painful intercourse.

In women, it appears on the labia but also on the lining of the vagina and cervix. If the initial infection occurs during pregnancy, the infection can also be transmitted to the fetus. Transmission also occurs during birth to the newborn.

In newborns, these infections are very severe, with general manifestations, blood poisoning, brain inflammation and even death, especially if the disease is treated late or untreated.

Genital warts are found on the external genital organs. But in some cases they also form on their internal mucous membranes. Like genital herpes, they can also occur around the anus.

In addition to genital rashes, they also cause pain, burning, itching. They are caused by the HPV virus. Of the HPV types, however, they do not cause cervical cancer.

AIDS can also have cutaneous manifestations. Skin infections and diseases occur on the basis of impaired immune function. Their symptoms include rashes, enlarged lymph nodes, also fever, inflammation and others.

Digestive system

Very often, a rash is also present in some diseases of the digestive system. For example, in diseases of the colon, such as ulcerative colitis. In this case, it is an inflammatory disease causing ulcers in the colon.

Chronic inflammation of the digestive tract (small intestine, colon and sometimes oesophagus) is typical of Crohn's disease. Although its most common symptoms are diarrhoea, abdominal pain and fatigue, a rash can also be observed.

Along with ulcerative colitis, they have various complications. One of them is also a skin disease. It can have various skin manifestations and also a rash.

In humans, various aphthae, white rashes on the gums, oral mucosa and rash on the tongue can be found as a symptom.

If a person has celiac disease (his intestine does not process gluten), this disease can also manifest itself in a rash similar to a cold sore on the elbows and knees, as well as a rash on the face.

A minor rash may occur on the abdomen when the liver is damaged. For example, in cirrhosis of the liver, there is chronic necrosis of the liver cells. The liver cells are replaced by connective tissue, and so the liver is rebuilt.

The rash also accompanies several febrile diseases, including Kawasaki disease, which is less common but most often affects young children. In this disease, the small and medium-sized arteries become inflamed.

Other diseases also have different skin manifestations, whether they are systemic diseases affecting several organs or diseases of specific internal systems.