What causes skin rashes?
Skin rash can suddenly appear at different parts of the body and look quite different: for example, spots, blisters or scales can form on the skin. Infectious diseases such as chicken pox or measles can be behind the skin rash. There are also allergies or various skin diseases including psoriasis or neurodermatitis. Here you will learn what skin rash mean and how it is treated.
The human skin consists of about two billion skin cells, which protect the body against pathogens, sun radiation, sun exposure, excessive heat loss, dehydration and also from overheating. The skin is also the largest organ of the body. Skin covers an area of about two square meters and weighs a total of ten kilos in an adult human being.
The skin usually responds immediately and visibly to external and internal influences – with a rash that can also extend to larger areas of the skin. The skin rash may consist of colored spots, liquid-filled vesicles, pustules, wheals or nodules. Based on the appearance of the rash, dermatologists can often close the cause. Itchy rash is not uncommon – the itching is a frequent concomitant symptom. The rash can also cause burns or pain or a feeling of warmth.
“Eczema” is a collective term for inflammatory skin diseases, but these are not contagious. In principle, external or internal factors can cause eczema.
The skin changes can in principle affect the whole body, but they can also be restricted to individual areas. Some people have skin rash on the face, others on fingers, hands, knees, legs, feet, toes, elbows, forearms, abdomen, or back. The mucous membranes in the mouth and throat or the skin on the genital organs can also be affected.
Skin rash causes and possible diseases
Skin rash can have quite different causes. Infectious diseases such as chickenpox or measles, allergies and various skin diseases such as psoriasis or neurodermatitis can be behind this.
The three-day fever is a contagious disease caused by viruses. In addition to high fever, a delicate, red, itchy skin rash develops on the chest, abdomen and back. This can spread to arms and legs, but disappears after a few days.
Scarlet fever is a typical childhood disease caused by infection with bacteria (streptococci). Typical among other things, skin rash is caused by the toxins of the bacteria. It begins with small redness in the flexion folds of the armpit, the chest, and the inguinal region, and spreads out over the whole body. In some patients the rash is absent or is only slightly pronounced. The skin rash disappears after three to five days.
Measles is also a childhood disease that is triggered by viruses and is highly contagious. That is why it is spreading rapidly. Here too, skin rash is characteristic. Behind the ears and at the side of the nose are red, irregular patches, which soon fuse and cover the whole body. Smaller bleeding may occur. The skin rashes off after about five days.
Rubella causes skin rash
Rubella is triggered by a virus infection. The rash begins behind the ears with small bright red or slightly brownish spots. They spread to face, neck, arms, legs and then to the whole body. Itching rash rarely occurs in rubella. After one to three days the rash disappears.
Erythema infectiosum causes skin rash
Erythema infectiosum is an infectious disease caused by the Parvovirus B19. The butterfly-shaped skin rash is characteristic in this disease. However, butterfly – shaped skin rash does not develop in all patients. The skin rash develops first in the face (cheeks, nasal root) and spreads itself after a few days on arms, legs (especially the stretching sides) and finally the whole body. Within seven weeks the rash can occur again and again.
The hand-foot-mouth disease causes skin rash
The hand-foot-mouth disease is triggered by Coxsackie virus type A. On the skin (hands, feet) a red, itchy skin rash with blisters and nodules forms, which later goes into white-gray pustules.
Borreliosis causes skin rash
Borreliosis is an infectious disease that is usually transmitted by ticks. Triggers of Lyme borreliosis are helical bacteria, so-called Borrelia. After a few days, a red spot may develop around the injection site, which gradually increases in size and is usually pale in the middle.
Chickenpox causes skin rash
Chickenpox (varicella) are caused by the highly contagious varicella zoster virus. They begin with an itchy, red skin rash – mostly on the trunk and the face. It spreads over the whole body, also on the hairy part of the head as well as arms and legs.
The mucous membranes (mouth, connective skins, genitals) may also be affected. The red spots turn into liquid-filled, highly itchy bubbles that gradually crust. The rash of the skin runs in relapses, so that new red spots are added daily to the already existing vesicles and crusts.
Other diseases that cause skin rash in people
Herpes zoster is a painful skin disorder caused by the varicella zoster virus. On the first contact, the herpes virus causes chickenpox. The typical skin rash consists of blisters on a swollen, reddened surface.
The rash runs belt-shaped from the trunk toward the sternum around the body. There may also be skin rash in the face and ear. After two or seven days, the blisters burst, small wounds are formed, which are gradually covered by scab. After two to three weeks, the scab usually falls off.
The Erysipelas is a locally limited, acute inflammation of the lymphatic vessels of the skin. A erysipelas is usually caused by certain bacteria (streptococcus). The bright red erysipelas is formed around the entrance point of the bacteria into the skin.
Impetigo contagiosa is a bacterial skin infection, which is very contagious. Staphylococci are the main cause of this condition. Typical for the skin rash are asymmetrical, sharply delineated, golden yellow, red-fringed crusts, which mainly occur around the mouth and nose as well as on the hands.
Scabies are caused by mites, which cause a severe itchy skin rash.
Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum. In the second stage of syphilis, skin rash usually occurs.
Typhus is a severe diarrheal disease caused by bacteria (salmonella). Here also pin-point-like red spots can form on the abdomen, chest and back, but they do not itch.
Dengue fever can also cause temporary skin rash. The cause of this tropical disease is the dengue virus.
Allergies which cause skin rash on the body
An allergy is a hypersensitivity reaction to certain substances that are usually completely harmless. The immune system fights these harmless substances and thus triggers an allergy.
Examples are pollen (hay fever), but also food or chemical substances such as nickel or cobalt. Skin redness and itchy rash are common signs of an allergic reaction from the instant type.
The allergy-inducing substances can have a skin-irritating effect directly on the skin (UV-radiation, cold), but also from the inside (by absorbing or inhaling with the food). This is the case, for example, with certain foods such as kiwifruit or nuts as well as medicines.
Contact dermatitis means that the skin itch, swell, soak or redden.The most common allergy triggers (allergens) are fragrances or metals, such as nickel. Even small traces of these substances are sufficient for allergy sufferers to stimulate immune defense.
Usually, the skin rash is formed at the site that is in contact with the allergy trigger. Especially allergies against fragrances are on the advance. The symptoms: rough, reddened or scaly skin and itching. If the allergen lasts longer on the skin, blisters, nodules and painful tears can develop.
The Hives (urticaria) is also one of the allergic diseases. The skin rash consists of red elevations. They look like mosquito bites or like after a contact with nettles.
Patients who are exposed to nutrients react sensitively to certain internal (foods such as strawberries) or external stimuli (coldness, pressure). They suffer from severe itching. Usually both the wheals and the itching pass within a day.
Sunlight can cause severe allergic skin reactions. It comes to agonizing itching, blisters. Often this is done in combination with cosmetics such as skin and sun cream or perfume. Polymorphic light dermatosis (PLD) is the most common of all solar energies.
Skin diseases that causes skin rash on the body
Skin rash may also be various skin diseases, which are not contagious. These include, for example, neurodermatitis and psoriasis.
Acne is a hormone-related disorder, which is mainly dependent on the male sex hormones (androgens). Acne often occurs during puberty. Typical are the white nodules, which sometimes have a black spot in the middle (blackheads, comedos). If the nodules become inflamed, a pimple with a pus is formed.
Seborrheic dermatitis is a harmless skin rash. It is caused by overproduction of the sebaceous glands of the hairy scalp.
Neurodermatitis (atopic dermatitis, atopic eczema) leads to recurrent skin infections with itching. The skin is extremely dry. In babies, the neurodermatitis appears as a milk scab on the scalp, later as a red itchy rash especially in the face.
The eczema spreads on the neck over the trunk and towards the nappy region. In older children and adults, eczema can occur throughout the body.
Psoriasis is a chronic inflammatory and recurring skin disease in which large amounts of dandruff are formed on the skin. The rash is noticeable due to sharply limited, reddish and slightly flared stains.
lichen planus is a rare skin disease, in which there are strongly itchy, reddish nodules (usually inside of the wrist and ankles, lower legs). Probably an autoimmune reaction is responsible.
Other causes of skin rash in people
Skin rash can also be a side effect of medication. Drugs that can trigger skin rash on the skin of people.
Rosacea is an inflammation of the facial skin that runs chronically. The disease may be differently pronounced. Depending on the degree of severity, there is a persistent redness with conspicuously enlarged veins in the face. Later, skin rash with nodules and vesicles may occur.
Lupus erythematosus is an autoimmune disease. Typical is the butterfly-shaped skin rash on the left and right of the nose (butterfly erythema).
Stress and psychological stress can also lead to a skin rash or strengthen it.
Skin rash: When should you see a doctor?
Often the rash is simply caused by a wrong detergent or a cream. It usually forms back when you avoid the substance. Even in infectious diseases, it often disappears after a few days. However, you should visit a doctor if :
- You suddenly get violent skin rash
- The cause of skin rash is unclear
- The skin rash extremely itchy, aches or swell form
- The skin rash spreads to other areas of the body and does not recur
- In addition to skin rash symptoms such as fever, dyspnea, and other
- The rash of the skin develops in succession
- The skin rash changes
- With babies and children who have skin rash, you should always consult a doctor
Skin rash: What does the doctor do?
It is important to determine the extent to which the skin is located (localization) at which the skin rash occurs. In the case of spots on the trunk, the extremities and the face, it is often scarlet. Skin infections in the face and neck often cause virus infections.
It is also tested whether the mucous membranes (mouth, genital area) are infected (for example, chickenpox and scarlet fever). A role is also played by symptoms such as fever, cough, runny nose, or itching.
Physicians look at the skin rash precisely, because the appearance of the skin rash is indicative of the cause. The following forms are distinguished:
- Dots (macules)
- Hives (urticae)
- Dry and wet areas
In chickenpox, several different forms of appearance can coexist simultaneously. They can blend into each other.
The time course of the skin rash also helps in the diagnosis: Does it spread? Which body regions? Does it run in the form of a reed? Does it change?
In order to make the right diagnosis, further tests are sometimes necessary, for example a smear (detection of fungi), a tissue sampling (biopsy), blood tests (viruses, bacteria) or allergy tests.
The therapy depends on the cause of the skin rash. Antibiotics only act against bacteria. Anti-fungal agents are used for antifungal infections and virostatics for viral infections.
Against itching you can use ointments and creams with antihistamines. Skin diseases are usually treated locally, that is with ointments, creams, tinctures or bath additives containing certain active ingredients. Examples are ointments with urea or tar.
You can do it yourself for skin rash
The best protection from skin rash is a healthy skin. And these can help you so that it can keep pathogens well in check.
A healthy protective film on the skin is slightly acidic – so it can protect bacteria and fungi best. Therefore, use body care products with neutral pH. A pH value of 5.5 corresponds to the natural acid content of the skin surface (neutral value is 7.0). Basic products with a pH above 7.0, for example, soap, destroy the acid protection coat of the skin.
Avoid allergy triggers
Always look at the list of ingredients for creams. Perfume and preservatives can trigger an allergic reaction and thus stimulate itching. It is best to sample body care products and observe how your skin responds.
Keep aggressive substances away from your skin
They are used among other things in washing lotions for hands, dishwashing detergents, detergents, chemical hair dye products or in highly chlorinated swimming pool water. Wear protective gloves when handling with such substances.
What to wear for skin rash
Your skin needs fresh air. Look for loose, breathable clothing – preferably cotton. Extreme cold is bad for the skin and can cause it to dry out and cause skin rash