What causes itchy and red patches on the skin?

Among the symptoms of many dermatologic and a number of infectious diseases, itching and red patches of various shapes and locations are common. It is important for patients to remove these spots and get rid of the itching, but in order to achieve this and ensure proper treatment, it is necessary to find out their etiology.

It should be borne in mind that such signs occur in some systemic diseases, and an accurate diagnosis can only be made when seeking medical help.

Causes of the itching and red patches on the skin

Is it possible to brush over all potential causes of itchy erythematous macules - red patches in various diseases and conditions?

Most often these skin elements are maculopapular in nature, that is, they consist of flat red spots visible to the naked eye and limited reddened areas (papules) slightly raised above the skin. The rash can also be very small.

Medics take into account not only the size, specific localization, speed of appearance of spots and their subsequent transformation, but also the preceding and / or concomitant symptoms. More information in the materials:

• Why did red spots appear on the body?
• Types of red spots on the skin of the body

In pediatric practice, first of all, consider childhood infections accompanied by rashes on the skin (rubella, chickenpox, measles, scarlatina), as well as diathesis and dermatitis.

Itching and red spots on the body

In addition to the above infectious diseases, when children under five years of age are infected with Coxsackie enterovirus of the Picornaviridae family and develop the so-called hand-foot-mouth syndrome - with the appearance of fever, myalgia, respiratory and intestinal symptoms - there are itching and red spots on the body, limbs and face (near the mouth), which very quickly turn into vesicles. [1]

Both in children and adults itching and red spots on various parts of the skin can be associated with: insect and arthropod bites (for example, a tick that carries Borrelia bacteria - the causative agent of Lyme disease); [2] atopic and allergic conditions (with the use of certain foods, stress, etc.); with red flat lice; with a localized form of scleroderma (autoimmune skin pathology; with the side effects of the use of antimicrobial antibiotics and allergic (with the use of certain foods, with stress, etc.).); with red flat lice; [3] with localized form of scleroderma (autoimmune skin pathology); [4] with side effects of antibacterial drugs and a variety of other drugs - in the form of allergic urticaria, [5] erythema multiforme [6] or toxic-allergic Stevens-Johnson syndrome. [7]

Slightly flaky red patches and itching on the abdomen and chest (sometimes with preceding slight fever) appear in the manifestation of pink lichen (Pityriasis rosea), which is usually diagnosed at a young age. [8]

Allergodermatosis is a type of allergodermatosis that occurs on the body as a small, barely visible red rash and itching in people with low gastric acidity. Such skin manifestations are noted in the presence of parasites in the intestine or its bacterial infection.

The localization of itchy, hyperemic macules in the axillae is most often simple contact dermatitis, which can be caused by deodorant, depilatory products, detergents, clothing fabric or laundry powder. [9] But when small red spots and itching under the armpits, on the sides and abdomen, on the soles of the feet and palms of the hands occur in parallel with symptoms such as abdominal pain, nausea and diarrhea, we may be talking about an enterobacterial infection - yersiniosis. [10]

The Epstein-Barr virus (family Herpesviridae), which leads to infectious mononucleosis, also causes itchy red rashes on the skin of the trunk and upper extremities in some cases. [11]

Itching and red spots on the face and neck

Pruritis-associated skin hyperemia - a red face and itching - may be the first sign of facial allergies. In addition, itching and causing

Mild burning red patches on the face are among the symptoms of perioral dermatitis, [12] erythematous type of Beck's disease - sarcoidosis, [13] irritant contact and allergic contact dermatitis, cold erythema and photodermatitis. [14]

Signs of erythematous-teleangiectatic skin lesions - rosacea [15] and erythema in systemic lupus erythematosus [16] are red nose and itchy skin of the nasolabial folds. With itchy red macules around the mouth and nose, the development of nebulosal impetigo, associated with the invasion of the skin and subcutaneous tissues by Staphylococcus aureus (Staphylococcus aureus), begins. [17]

And in the case of erythematous form of primary (rye) inflammation, caused by β-hemolytic Streptococcus pyogenes group A, simultaneously with fever, headache and general weakness, red spots framed by thickened skin appear on the face. [18]

Red patches in the mouth and itching are possible with allergies, flat red rash, strepto- and staphylococcal infections.

Symptoms of eyelid dermatitis, allergic irritation (hay fever), [19] as well as fungal lesions of the eyelids include red eyes and itching.

Redness and itching of the cheeks (with gradual spread of erythematous macules and papules to the extremities and trunk), often accompanied by respiratory symptoms and general deterioration of the condition, is manifested by infection with parvovirus B19 (family Euthyphoraviruses), which is the cause of infectious erythema (synonyms - fifth disease or slap syndrome). [20]

Red neck and itching are most common in contact dermatitis and Stevens-Johnson syndrome (the latter with myalgia and high body temperature).

Itching and red patches on the extremities

Most of the causes previously cited can cause itching and red spots on legs and arms.

Crusting red patches on the palms and itching are most often associated with eczema of the palms, [21] also known as atopic dermatitis, [22] which can occur in the creases of the elbows, under the knees, under the armpits, and in any folds of the body.

If there is itching and a red wound between the fingers of the hands, it means that the excoriation of the eczematous spot led to its bleeding, or the dryness of the skin at the site of the rash in atopic dermatitis caused its cracking (with the release of transparent exudate).

Red or purplish rashes on the palms and fingers, as well as on the shoulders and upper back are seen in dermatomyositis. [23]

When infected with the fungus Trichophyton rubrum, dermatologists diagnose rubrophytosis of the skin of the feet, hands, face, and nails, symptoms of which include reddening of the skin on the hands, red feet, and itching.

Itchy red patches on the palms and soles - accompanied by fever, vomiting and headache - are seen in almost 75% of meningococcal infection (Neisseria meningitidis) cases and the development of inflammation in the brain membranes (meningococcal meningitis). [24]

Diffuse macular erythroderma - a rash of red patches usually localized on the palms of the hands and feet - and symptoms such as fever, decreased BP, confusion and lack of external reactions are indicative of infectious toxic shock. This condition, like toxic-allergic syndrome, is classified as an emergency.

Itchy red patches on the shins are secondary to rusty inflammation and sarcoidosis; skin vasculitis of the cutaneous type is seen on the skin of the shins and feet.

Also read:

• Types of red spots on the skin of the feet in various diseases
• Causes of red spots on legs

Red spots and itching in the groin can have different etiologies, but the most common cause is considered to be dermatophytosis (fungal infection) and contact or atopic dermatitis.

In men with condom allergy or acute balanoposthitis, [25] inverse psoriasis or Reiter's syndrome [26] there is itching and red patches on the head of the penis.

In women, red labia and itching are associated with STDs and genital infection caused by herpes simplex virus, [27] and, in postmenopausal women, with leukoplakia of the external genitalia. [28]

Risk factors

Risk factors for the appearance of itching with red spots - the development of diseases and conditions causing these symptoms. Thus, contamination with viral or bacterial infections is increased in places where there is a high probability of their spread (by contact with sick people).

Due to the weakness of the immune system, risk factors include early childhood and old age, as well as the period of pregnancy with physiologically determined immunosuppression. Poor sanitary conditions and insufficient personal hygiene "help" to catch fungal infection.

A negative role is played by the uncontrolled use of medications, increased sensitization of the body (according to some data, contact dermatosis affects 15-20% of the population) and genetic predisposition to allergic and atopic conditions.

Pathogenesis

Red spots are elements of inflammation or immune reaction (local or systemic) with local dilation of skin capillaries and structural changes in the cells of its superficial layers. Their pathogenesis is determined by the characteristics of diseases in which this symptom appears.

For example, contact or atopic dermatitis is provoked by an immune reaction to sensitizers with an increase in the synthesis of antibodies - immunoglobulin IgE.

The mechanism for the development of cold erythema (in some cases accompanied by a sensation of itching) is seen as an inborn disorder of thermoregulation due to problems with the metabolism of the CNS mediator serotonin.

The impact of pathogenic bacteria and viruses is explained by their release of cytotoxic substances in response to the defense mechanisms of the immune system. Bacterial and viral exotoxins for the body are antigens that are recognized by immunocompetent T-lymphocytes, which activate the protective response in the form of inflammation. And other symptoms, as in cases of infectious-toxic shock, are the result of viral and bacterial toxins entering the bloodstream.

The sensation of itching originates in the superficial layers of the skin and mucous membranes, where there are nerve endings that respond to the release of mast cells of the skin neurotransmitter histamine and its release into the blood. Impulses of itching through afferent fibers are transmitted to the spinothalamic tract, and from there to the somatosensory cortex of the brain. For more information, see the publication - Pathogenesis of itchy skin.

Complications and consequences

First of all, scratching rashes "open the way" for secondary infection of the skin, so it may be inflamed with the appearance of pustules filled with serous exudate. In addition, excoriation of itchy spots can lead to the formation of scars.

Other effects and complications depend on the cause of these symptoms and may include:

• in reaction to medications - angioedema;
• in non-bullous impetigo - transformation of inflammation into a bullous (vesicular) form;
• in infectious erythema caused by parvovirus B19 - anemia;
• Coxsackie virus infection - conjunctivitis (including hemorrhagic), aseptic meningitis, myocardial pathologies, nervous system damage.

Diagnostics of the itching and red patches on the skin

Given the wide range of causes of pruritic erythematous macules, diagnosis is often difficult.

In addition to physical examination and anamnesis, blood tests are required: general and gross, for eosinophils, for the level of antibodies (IgE) and C-reactive protein, immunoenzyme analysis, etc. It is also required to pass a general urine and fecal analysis, bacteriological examination of scrapings from the spots. And in allergic dermatitis, skin tests are performed to identify sensitizing substances.

We use instrumental diagnostics with dermatoscope, Wood's lamp, if necessary - ultrasound of the skin and subcutaneous fat.

More details in the articles:

• Skin examination
• Diagnosis of itchy skin

The presence of nonspecific symptomatology in the appearance of hyperemic maculopapular rashes and pruritus can make it difficult to determine their true cause, so in solving this problem helps differential diagnosis with the participation of doctors of different specializations.

Treatment of the itching and red patches on the skin

There are various techniques according to which diseases with these symptoms in the clinical picture are treated.

Thus, the presence of bacterial infection (with impetigo, rusty inflammation, balanoposthitis, STDs, etc.) requires the use of systemic antibiotics prescribed by a doctor, taking into account the spectrum of their effect on the identified pathogens.

Antiviral drugs based on interferon are ineffective in skin manifestations. For example, DNA viruses of the Herpesviridae family cannot be removed from the body, but their activity can be suppressed with acyclovir-based products.

And to treat fungal infections use effective ointments for fungus.

Simple and allergic contact dermatitis as well as allergic urticaria require etiopathogenetic therapy with maximal elimination of irritating factors and allergens.

Treatment of itchy skin can be systemic and topical. In the first case antihistamines and glucocorticosteroids are taken, in the second case topical agents are used:

• Itching ointment
• Creams for itching
• Ointments for skin rashes
• Eczema creams
• Ointments for allergic dermatitis

Prevention

Most childhood infectious diseases are prevented by vaccinations (immunizations).

Prevention of allergodermatoses consists in the elimination of sensitizing factors.

But against many idiopathic dermatologic and systemic diseases of autoimmune origin there are no specific preventive measures yet.

Forecast

The most common infectious diseases of childhood have a completely favorable prognosis.

As for autoimmune dermatologic pathologies, they, alas, run in chronic form (with periods of remission), but they are not life-threatening.

According to clinical statistics, meningococcal infection (in the absence of timely intensive care) is fatal in 9% of cases, and in Steven-Johnson syndrome - in 16-27%.