Itching (Pruritus): Description

Brief overview

  • Treatment: skin care, cotton gloves to prevent scratching while sleeping, airy clothing, cool compresses, relaxation techniques, treatment of the underlying condition.
  • Causes: Allergies, psoriasis, eczema, parasites, kidney and liver diseases, diseases of the blood and lymphatic system, metabolic disorders.
  • Diagnostics: patient interview (anamnesis), physical examination, blood test, smears and tissue samples, imaging procedures (such as ultrasound, X-ray)

How and where can itching manifest itself?

Itching (pruritus) triggers the desire to scratch the corresponding area. The area of skin that itches sometimes looks normal, in other cases it is altered by a (skin) disease. If the itching does not subside after six weeks, doctors speak of chronic pruritus.

Whether the itching occurs on the face, back, back of the knee, hip or upper body depends on its cause: Sometimes an allergy or a skin disease such as neurodermatitis (atopic eczema) is behind it, sometimes it is a fungal infection or simply dry skin. Depending on the cause, the itching varies in severity. Sometimes it is present day and night, sometimes the itching only occurs when you come to rest.

Origin of itching

For a long time, it was assumed that itching is triggered by the same nerve endings as the pain stimulus. However, more recent findings suggest that it is a separate subgroup of nerve fibers that are excited by certain neurotransmitters, first and foremost histamine and serotonin. This thesis is supported, for example, by the fact that opiates inhibit pain but trigger itching.

Scratching produces pain stimuli that mask the itching for a short time and provide relief. However, the mechanical stimulation of the skin releases messenger substances, which in turn promote itching – a vicious circle develops. Those affected sometimes perceive the itchy skin as burning or slightly painful.

Classification of itching

Itching can be divided according to the nature of the skin:

  • Pruritus cum materia:The itching is based on an already clearly visible skin disease.
  • Pruritus sine materia:In this case, the skin still appears visibly healthy and without changes.
  • Pruritus with chronic scratch marks:Here, the skin is scratched to such an extent that it is no longer apparent whether a skin disease is underlying it.

What helps against itching?

What you can do yourself

Regardless of the cause of the itching – remedy and relief you can often create even with simple tips:

  • Avoid dry skin:Refrain from a dry room climate, frequent showers, baths, sauna sessions or care products that contain alcohol. Dry skin is often also itchy skin.
  • Reduce irritating factors: Very spicy food, alcohol, stress, excitement and anger often cause itching. Try to limit these factors in your life.
  • Take a skin-friendly bath:A bath in lukewarm water for no more than 20 minutes replaces a quick shower. When doing so, refrain from using drying shower gels. Do not scrub the skin with a towel in the case of skin diseases or severe scratch marks, but dab gently. Then re-lubricate with lotions.
  • Choose airy clothing:Wear loose clothing that does not chafe the body or irritate the skin, such as cotton.
  • Provide quick relief:In case of sudden onset of severe itching, cool, moist compresses with yogurt or a little vinegar help. Poultices with black tea are also good. With all moist compresses, apply cream to the skin again afterwards. Lotions with urea or menthol cool and moisturize itchy skin.
  • Use relaxation techniques:Some methods such as autogenic training, progressive muscle relaxation or yoga not only help to reduce stress, but are also intended to distract from scratching, especially in cases of chronic pruritus.

Medical treatment

Treatment always depends on the underlying disease and varies accordingly.

What can be the causes of itching?

Itching can have various causes. The possibilities range from insect bites to skin diseases to systemic diseases.

Skin reactions and skin diseases

Skin reactions (such as to rapid temperature changes) and skin diseases are the main causes of itching. For example, pruritus has the following triggers:

  • Neurodermatitis (atopic eczema): This is manifested by severely itchy skin areas, sometimes accompanied by redness and blisters. Itching of the arms and crooks of the arms as well as the back of the knees is typical. The hands, feet and neck are also frequently affected.
  • Psoriasis:In psoriasis, scaly, itchy areas of skin form on a reddened background. These develop especially at the hairline, elbows and knees.
  • Fungal infection:An infestation with the skin fungus Candida causes an itchy reddening of the skin in the armpits or (in women) under the breasts, which sometimes smells unpleasant, especially in the skin folds. Other fungal diseases are also possible, for example a groin lichen (tinea inguinalis). Here, the inner thighs and groin area often itch.
  • Parasites: Scabies (scabies mite) in particular deprives many people of sleep; itching often occurs in the evening and at night, and in warm weather.
  • Environmental factors:Toxins released from an insect bite, plants, chemicals or parasites often cause pain in addition to severe itching.
  • Aquagenic pruritus:Here, a stinging itch occurs due to contact with water or temperature changes in the air.
  • Dry skin:Scaling skin when flaking summer tan, lack of moisture, showering or drying skin care products cause itchy skin.

These autoimmune diseases are manifested by various symptoms, but all have itchy skin in common.

Diseases of internal organs and organ systems

Many other diseases are also accompanied by itching:

  • Kidney diseases:A large proportion of patients with severe kidney failure who receive blood purification (dialysis) suffer from severe, generalized itching shortly after therapy. The exact causes are still unclear.
  • Thyroid disorders: Overheated, itchy skin is common in hyperthyroidism. Pruritus is rare in hypothyroidism.
  • Diabetes mellitus: Nerve damage (neuropathies) as well as increased susceptibility to fungal skin infections sometimes cause itchy skin reactions in diabetics.
  • HIV infection: The immune deficiency favors skin diseases caused by fungi or parasites, which are inconspicuous but are sometimes accompanied by severe itching. Pruritus also sometimes occurs in the course of antiviral therapy.
  • Other infectious diseases: Chickenpox and measles are often accompanied by constant pruritus.
  • Polycythaemia vera: The thickening of the blood due to excessive formation of blood cells first appears as aquagenic pruritus (itching after contact with water).
  • Anorexia nervosa, gluten intolerance, or malnutrition sometimes accompany itching.
  • Neurological diseases: Damage to the central nervous system, as in multiple sclerosis (inflammatory disease of the central nervous system with symptoms of paralysis and stiffness), polyneuropathies (damage to peripheral nerves, for example in the arms or legs), or viral diseases such as herpes zoster (shingles).

Medications

There are quite a few medications that potentially cause itching:

  • Antibiotics
  • Opiates
  • Anti-inflammatories
  • Antimalarials
  • Psychotropic drugs (for the treatment of mental illness)
  • Hormones
  • Diuretics (drugs used for drainage, diuretics)
  • Cytostatics (substances that inhibit cell growth and/or division)
  • Antihypertensive drugs
  • Gold (gold compounds are or were used, for example, in rheumatism therapy)
  • Anticoagulants

Other causes of itching

In addition, there are other causes of itchy skin:

  • Hormonal fluctuations: Sometimes generalized itching occurs during pregnancy, during the menstrual cycle, or after menopause (climacteric).
  • Cancer therapies: Many cancer patients experience itchy skin as a result of therapy such as radiation or various medications.

Itching: examinations and diagnosis

The first contact person is the dermatologist, who recognizes skin changes and skin diseases. Doctors from other specialties (such as internists or psychiatrists) are called upon if the cause of the itchy skin is not “clear on the skin” but is hidden in the body.

Existing allergies, infestation of family members with parasites, recently visited vacation spots and the intake of medication also provide the doctor with important clues as to the cause of the itching. Also, mention any other complaints, even if they seem insignificant (for example, dizziness or weakness).

The physical examination includes palpation of the liver, spleen, lymph nodes and kidneys to detect organic diseases.

If the itchy skin appears for no apparent reason, further examinations follow. Blood tests can be used to detect changes in the liver, gall bladder, kidneys, as well as inflammation or other worrisome changes. In further tests, the doctor checks the blood for autoimmune diseases, for example.

If a disease of internal organs such as liver, kidney or tumor diseases is suspected, imaging examinations such as X-ray, ultrasound, computer tomography (CT) and magnetic resonance imaging (MRI) are often informative.

Itching: When to see a doctor?

Itchy skin after an insect bite or an allergic reaction is very unpleasant, but usually goes away on its own within a short time. These one-time events are no reason to see a doctor. However, if persistent itching occurs again and again for no apparent reason, it is recommended that a specialist take a closer look at the pruritus.

In general, it is recommended to see a doctor if:

  • The pruritus occurs for an unusually long time and for no apparent reason (all over the body)
  • Additional complaints such as fatigue, tiredness or fever are present
  • The skin shows other changes besides itching