Itchy rash

Rash: dermatitis and eczema

Itchy rash is a common symptom that can be caused by a variety of illnesses, allergic reactions or mental health problems. The rash occurs as an acute and chronic symptoms, in which sufferers, depending on the cause, duration and localization of the symptoms sometimes suffer from significant impairments in everyday life. Often, patients also have reduced self-esteem, especially if it is facial rash. The skin irritation should be best examined by a specialist (dermatologist or dermatologist) to determine the causes and exclude more serious diseases.

contents

• Rash: dermatitis and eczema
• definition
• Symptoms of itchy rash
• Typical signs of eczema
• Symptoms in case of acute rash
• Diagnosis of itchy skin lesions
• Diagnosis of eczema and psoriasis

definition

The itchy rash refers to a superficial irritation of the skin, which is described in the medical community under the terms dermatitis and eczema. Depending on the duration of the symptoms, a distinction must be made between acute and chronic rash, whereby the term rash is also used for the acute case.

Itchy rash may be manifested, for example, in the form of wheals or blisters. (Image: Jürgen Fälchle / fotolia.com)

Furthermore, a subdivision based on the visible skin changes, the so-called efflorescence occur. In this case, a distinction is made between primary sclerosis and secondary sclerosis. The primary lesions such as blisters, blisters, wheals, pustules, nodules or so-called macula and plaque are caused directly by the pathological lesions.

The secondary lesions such as dander, encrustations, abrasions, ulcers and scars, however, occur only as a result of the primary lesions or the human reactions to them. Here, for example, injuries of the skin surface by the fingernails during scratching into consideration.

Symptoms of itchy rash

The rash described is usually characterized by severe itching and changes in the color and texture of the skin. The rash is often confined to specific areas of the body such as the face, the armpits, armpits, hollows of the knee or the back, but can also occur over the entire body or surface. Depending on the causes of the skin change this takes on different forms, with an expansion of the affected skin surface is not uncommon.

Often the rash is confined to certain areas of the body such as the back, stomach or armpits. (Image: chaphot / fotolia.com)

Typical signs of eczema

In eczema, the itchy rash usually shows, despite different causes, a typical sequence of symptoms that begins in the acute stage with a slight erythema (erythema), caused by increased blood flow. For more severe reactions, it will produce bubbles containing clear liquid. These burst easily and then release the liquid. When drying the burst bubbles, a crust develops, which dissolves like scales from the skin.

The stage of blistering is referred to in the art as the stage vesicolosum. If the bubbles burst and begin to wet, the stadium madidans is reached. The subsequent crusting characterizes the stage crustosum, followed by the stage squamosum, in which the scales dissolve. In a chronic eczema course, the individual stages may be repeated or occur at the same time. The skin also tends to swell and often shows a coarser skin texture.

As a result of injuries, the skin surface is more susceptible to bacterial infections in eczema. These in turn may cause a further deterioration of the skin condition, which threatens a mutually reinforcing development of the disease processes.

Furthermore, fungal infections are favored by the eczema, whereby even the naturally occurring on the skin yeast fungi can cause a corresponding infection. In rare cases, a so-called eczema herpeticatum develops from the skin disease in conjunction with herpes simplex viruses. This can potentially lead to life-threatening blood poisoning and must be treated frequently with infusions in the hospital.

Symptoms in case of acute rash

An acute, itchy skin rash (exanthema) can be caused by various infectious diseases such as measles, rubella, scarlet fever or chickenpox. The rash usually takes on a disease-specific form and is associated with various accompanying symptoms such as fever and chills.

Other typical signs include circulatory problems such as dizziness, headache, sore throat, body aches, nausea and vomiting.

As an acute allergic reaction of the skin to food or medication, the rash occurs as part of the so-called hives (also nettle rash) on. Histamine increases the permeability (permeability) of the blood vessels in the skin due to the increased release of the messenger substance. The result is fluid retention in the dermis that leads to the formation of visible wheals, associated with redness and itching.

The hives can not only be caused by allergic reactions, but may also be due to physical effects such as heat, cold, pressure, water contact or sun rays, the symptoms are similar to the allergies.

Overall, the different concomitant symptoms and the efflorescence can provide important information on the causes of the rash and should therefore be taken into account accordingly in the diagnosis.

Diagnosis of itchy skin lesions

The diagnosis is due to the large number of possible triggers sometimes extremely expensive, but sometimes can be based on a simple inspection determine the cause of the symptoms. In the infectious diseases, the efflorescence in conjunction with the accompanying symptoms often already provides relatively reliable indications for the diagnosis. A blood test for corresponding antibodies serves only to secure the findings.

By a prick test, the dermatologist can detect if there is an allergy. (Image: Gerhard Seybert / fotolia.com)

If it is suspected that an allergic reaction causes the itchy rash, an appropriate allergy test can provide information. The extract of various allergens is applied to the skin as part of a so-called provocation test or introduced (prick test, intracutaneous test, scratch test) and observed the reaction after a certain period of time.

Furthermore, blood tests can provide information on existing IgE antibodies (immunoglobulin E), which typically occur in allergic reactions. However, a distinction must be made here between elevated IgE values ​​in the case of an allergy and the increased values ​​due to other diseases or parasitic infestations.

Fungal infections can usually be reliably diagnosed by the laboratory examination of a microscopic smear. In many cases, however, the appearance of the skin already provides relatively reliable signs of the fungal disease. If it is suspected that the infection has also spread to the organs, usually a tissue sample must be taken for diagnosis. Ultrasound examinations, gastroscopy and computed tomography (CT) also provide possible diagnostic assistance.

If parasitic infestation is the cause of the complaints, this can often be determined on the basis of the appearance of the skin and microscopic examinations. With a special magnifying glass, the so-called dermatoscope, it is possible, for example, to identify the drillings of the mildew in the case of scabies. Occasionally, even the tiny arachnids are directly visible.

The microscopic examination of a skin sample from the affected areas serves to secure the diagnosis. If there is a suspicion of cercariae, in addition to skin examinations, an examination of the bathing water can be helpful in the diagnosis. Safety provides here the checking of the blood for antibodies against the larval components.

Since metabolic disorders such as diabetes and hyperthyroidism as well as liver disease can lead to chronic itching, the presence of these symptoms in the diagnosis in case of doubt should also be checked.

If no physical causes for the itchy rash can be ascertained, a psychological examination of the affected person is a good option, since the skin irritations can also be due to mental problems. In detailed discussions with the patients, the therapists try to identify potential mental health problems of those affected, in order to derive methods that may be suitable for a treatment.

Diagnosis of eczema and psoriasis

Eczema is diagnosed on the basis of different main and secondary criteria, with the itchy rash being one of the characteristic external features. Dry skin is also a typical symptom of atopic dermatitis.

However, since these skin problems can also occur in a variety of other diseases, the differential diagnosis is essential here. The itchy rash of atopic dermatitis is to be differentiated from allergic skin reactions, metabolic diseases, diseases of the immune system, psoriasis and scabies.

Signs of psoriasis are sharply defined redness with silvery-white scales. (Image: Milan Lipowski / fotolia.com)

The most important clue in the diagnosis of psoriasis is efflorescence. When scratching with a wooden spatula, bright scales form on the affected areas, which in their consistency remind of candle wax. When removing the dander, sometimes the last thin cuticle, which forms the border to the dermis, dissolves. As a result, punctate bleeding is often seen.

Both the candles waxy scales and the peelable thin cuticle and the punctate bleeding are considered to be typical signs of this form of dermal lichen. The microscopic examination of removed skin samples can serve to secure the diagnosis. Since many (skin) diseases are similar in their appearance to psoriasis, the differential diagnosis is also of particular importance for the skin disease.
(fp, nr, last updated on 15.05.2018)

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Causes rash
Treatment itchy rash

Specialist supervision: Barbara Schindewolf-Lensch (doctor)