Causes and pathogenesis of streptoderma

Streptoderma is a disease that almost everyone has encountered, although not everyone suspected it. The causes and pathogenesis of streptoderma are in many ways similar to the etiology and mechanism of development of other infectious diseases, but still has its own characteristics. And the high prevalence of the infection cannot but be alarming. [ 1 ], [ 2 ] Belonging to the category of skin diseases, this pathology has a wide variety of its manifestations and is far from harmless, most often affecting children and people with weak immunity.

Is it really an infection?

How many of us, having discovered a sore in the nose or irritation in the corners of the lips, popularly called "angina pectoris", would suspect an infectious disease? In fact, these may be manifestations of streptoderma - a disease caused by coccal microflora, which includes streptococcus, staphylococcus, pneumococcus and some other representatives of the bacterial microflora living near us. At the same time, contact with bacteria can be so close and prolonged that you wonder how a person stays healthy for so long.

When considering the causes and pathogenesis of streptoderma, we come across the fact that although the coccal microflora has quite a large variety, this pathology, like any other infectious disease, has its own characteristic pathogens. It is believed that the symptoms of streptoderma arise under the influence of streptococci, which mainly affect the skin, which is why the disease is named.

Streptococci are spherical bacteria whose history goes back more than one millennium. Like other microscopic organisms, they existed even before the appearance of plants, animals, and humans. It is not surprising that over the long period of their development, bacteria have learned to adapt well to various environmental conditions and maintain their appearance, even in conditions of active struggle against them by humans.

Streptococci are considered to be "native" inhabitants of our skin and mucous membranes, that is, they coexist with us for a time without reminding us of themselves. For this reason, they are classified as opportunistic microflora, representatives of which provoke diseases only under certain conditions, namely, when the body's defenses are weakened, which allows microbes to actively develop and penetrate into the deeper layers of the skin and mucous membranes.

It is important to understand that streptococci are a generalized name for various types and strains of bacteria that are similar in structure. However, their effects may differ significantly. Some types of streptococci are not dangerous, peacefully coexisting with a person throughout his or her life. Others may even be useful, maintaining the normal microflora of the body. But there are also those that are associated with most infectious diseases (and not only skin diseases).

Such hidden parasites include beta-hemolytic streptococcus group A (Streptococcus pyogenes), which is capable of destroying red blood cells (erythrocytes) and is related to pyogenic bacteria, along with Staphylococcus aureus. It is pyogenic streptococcus that is considered the main causative agent of streptoderma and other infectious pathologies characterized by a rather severe course (tonsillitis, scarlet fever, endocarditis, glomerulonephritis, etc.).

But what is the peculiarity of this parasite, and how does it affect the body's tissues, causing their destruction? Studying the pathogenesis of streptoderma and other diseases caused by Streptococcus pyogenes, scientists have found that beta-hemolytic streptococcus is a bacterium that, during its existence, secretes several poisons and toxins that are dangerous to the human body. These include the specific poison streptolysin, which is capable of destroying red blood cells, as well as a special enzyme, leukocidin, which destroys cells of the immune system. [ 3 ]

In addition, Streptococcus pyogenes synthesizes the enzymes streptokinase, hyaluronidase, amylase, and proteinase, which help maintain the activity of the microorganism and help destroy healthy tissue along the path of infection. [ 4 ]

The fight against such a health violator is carried out only with the help of antimicrobial drugs (antiseptics and antibiotics). But the group A streptococci, resistant to radioactive radiation, are also gradually learning to resist antimicrobial drugs. Fortunately, there are much fewer strains of pyogenic streptococcus that are resistant to antibiotics than those among staphylococci and pneumococci.

Risk factors for the development of streptoderma

Skin infections are one of the most numerous groups of skin pathologies. This is due to the large number of their pathogens (bacteria, viruses, fungi, protozoa), which penetrate the upper layers of the skin from the outside or live on the surface of the skin, acquiring pathogenic power only with active reproduction, which is characteristic of coccal microflora.

Usually, human immunity inhibits active reproduction of cocci, and individual low-active individuals do not pose a particular danger. But there is a certain part of microorganisms that can weaken the body's defenses. This is also typical of hemolytic streptococcus, which is considered the culprit of streptoderma and other infectious pathologies. It turns out that even good immunity does not always help to avoid the development of the disease, although it significantly reduces its likelihood.

Consideration of the causes and pathogenesis of streptoderma allows us to determine the risk factors that make some people more sensitive to the effects of infection, while others do not experience any problems from being in close proximity to microbes:

• One of the main and most common causes of streptoderma is the presence of small or large lesions on the surface of the skin that disrupt the natural protective barrier and allow microbes to penetrate into the body.
• The second reason is insufficient hygiene of the skin and mucous membranes, because a violation of the integrity of the skin is not yet a guarantee of infection of the wound. But on the other hand, excessive passion for hygiene procedures can play a cruel joke, disrupting the pH of the skin and thereby reducing its protection from microorganisms.
• Although streptococci have learned to somewhat reduce local immunity, with the well-coordinated work of the immune system they still do not have much chance of unhindered reproduction, while weak general immunity is unlikely to be able to restrain this process.
• Inadequate functioning of the immune system causes the development of allergies in humans. If the latter has external manifestations (rashes and itching on the skin), there is a risk of scratching the tissues with a violation of the integrity of the skin. But microscopic organisms are able to penetrate even the smallest wounds, invisible to the naked eye. [ 5 ]

But let us still focus on the immune system, since it is the main defender against various types of infections, and consider what factors can make its work insufficient to perform its main function:

• As is known, chronic diseases deal the biggest blow to immunity, regularly weakening our body. That is why people with long-term illnesses have a higher risk of developing infectious diseases, including streptoderma. Those who have chronic skin diseases or internal pathologies that cause wounds on the skin (for example, diabetes) are considered the most vulnerable to infection. At the same time, streptoderma that occurs against the background of such diseases will also be chronic.
• A complete balanced diet, optimally distributed over time so that the body regularly receives the nutrients it needs to support the work of all systems, including the immune system, reduces the risk of infectious diseases. If the diet is irregular, depleted of vitamins and microelements, you cannot count on strong immunity, which means the risk of infections increases.
• Various types of intoxication weaken not only the nervous system, but also other body systems that it controls. It is not surprising that after poisoning, the immune system is noticeably weakened and a person can easily catch an infection.
• Particular attention should also be paid to our mental health. Many people know that stress factors negatively affect the immune system. But not everyone knows that frequent nervous tension can also cause external reactions, so-called autoimmune skin diseases (for example, psoriasis or eczema), in which the barrier function of the skin is disrupted, which gives the infection a lot of room to develop.
• Immunity can also be reduced during respiratory infectious diseases. Viral infections are considered especially dangerous in this regard, as they significantly weaken the immune system. If measures are not taken to restore it during and after the illness, when in contact with a patient with streptoderma, you can see skin manifestations of the disease in yourself a few days later.

Moreover, streptoderma can easily be acquired during illness. For example, streptoderma is considered common after chickenpox – an acute viral disease with multiple rashes all over the body, which most people suffer from in early childhood.

The ulcers formed at the site of papules and vesicles are an easy way for infection to penetrate, and since they appear in large quantities, it is easy for a native inhabitant of the human skin and mucous membranes to penetrate through them deep into the body in several places, thereby manifesting the development of a severe form of the disease. At the same time, chickenpox may already be on the wane (rashes appear within 2-9 days), while the first symptoms of streptoderma suddenly appear.

Vitamin deficiency in the body (avitaminosis), helminth infection, exposure to negative environmental factors (radiation, chemical and thermal damage, drying effect of wind on the skin) along with the above factors affect the protective properties of our body and can be considered as risk factors for the development of streptoderma. Thus, you can protect yourself from the disease only if you simultaneously meet three main conditions:

• prevention of acute and chronic diseases,
• strengthening the immune system, which is facilitated by a healthy diet and an active lifestyle without bad habits,
• maintaining skin hygiene.

However, such preventive measures are more relevant for adults and teenagers than for children, whose immune system is still in the development stage and therefore cannot cope with the infection on its own.

Who gets sick most often?

The causes and pathogenesis of streptoderma help to understand which people are at risk. Despite the fact that statistics claim the presence of streptococci on the skin and mucous membranes of almost 100% of the population of our planet, the disease does not develop in everyone.

Most often, streptoderma is diagnosed in preschool children due to the insufficiently formed immunity and the characteristics of the child's skin. Children's skin is delicate and thin, so various types of microdamage can easily form on it. And if we consider that the barrier function of the child's skin is still weak, then the risk of streptoderma, as one of the infections, will be especially high.

In addition, small children do not always carefully observe hand and face hygiene, not to mention other areas of the skin. Those who are not yet able to take care of themselves depend on their parents, and moms and dads in their desire for excessive cleanliness and sterility often only harm their child, whose skin pH is disturbed and a strong immune system is not formed.

Women are also at risk, because their skin is also more delicate than men's. This causes frequent damage to the skin, and streptococcus can easily penetrate the body through wounds. The risk of infection in adult women and girls increases during pregnancy, when the body of the expectant mother undergoes hormonal changes and the body's defenses weaken.

Men whose professional activities or hobbies are associated with a high risk of skin injury, especially to the hands, where there is always plenty of bacteria, should not relax either.

Animal and insect bites, scratches, prickly heat and diaper rash, wounds, scratches and burns, cracks that form on excessively dry skin contribute to the penetration of infection deep into the body and increase the risk of streptoderma, regardless of gender and age.

It is clear that there is a high risk of infection in people with immunodeficiencies, chronic vitamin deficiencies, chronic diseases, skin diseases of any nature, especially during periods of exacerbation and the appearance of external symptoms.

Is streptoderma contagious or not?

There are a great many infectious diseases today, and most of them are considered dangerous to others. It is not surprising that upon hearing about such an infection as streptoderma, we will naturally ask whether the disease is transmitted from person to person and what are the ways of infection?

Speaking about the pathogenesis and causes of streptoderma, we mentioned that streptococcus is a bacterium that lives on the surface of the skin and mucous membranes of a person, which means that it is easy for it to change its host, moving to the body of another person. In a patient, bacteria are no longer present on the skin in a single quantity, therefore, when in contact with another person or object, they can remain on the skin and surfaces in large groups, ready to act in appropriate conditions.

Given the microscopic size of the parasites, we cannot see this, but as soon as we touch this cluster with a damaged area of skin, the bacteria will seize the opportunity to parasitize in the conditions of the human body that are suitable for their life and reproduction.

Speaking about the ways of infection with Streptococcus pyogenes, it should be noted that in most cases we are talking about the contact route of infection transmission, which means that its source can be not only the patient's skin, but also bedding, toys, clothes, i.e. any household items with which the patient has come into contact. This explains the high prevalence of infection in children's groups (kindergartens, nurseries).

It is also possible that the infection can spread through the air, where it can settle on the mucous membrane of the nose and mouth (especially in the corners of the lips), but such cases are rarer.

Who poses a danger to others? Firstly, patients with streptoderma, since their skin is a breeding ground for infection, especially in the area of local foci. Secondly, patients with respiratory infections, such as tonsillitis, often caused by Streptococcus pyogenes, can be considered a source of streptococcal infection. An identical situation is observed with scarlet fever, which is also a severe contagious disease. [ 6 ]

The source of infection can be considered not only those people who have skin manifestations of streptoderma, but also those who have become infected but do not yet know about their illness. A person can be considered contagious from the moment of infection, while the first symptoms may appear only after 7-10 days. At the same time, people who have once had a streptococcal infection can develop immunity to it, and if infected again, they will be asymptomatic carriers of the infection. [ 7 ], [ 8 ]

The same applies to people with strong immunity and no skin lesions. When in contact with a sick person, they can become carriers of the infection and be dangerous to others whose immunity is not so strong, for example, people from the risk group.

Any dermatologist will tell you that streptoderma, although caused by opportunistic microflora, is a highly contagious disease. And given that strong immunity is more of a dream than a reality for many, there is a high risk of infection if the patient is not isolated. And here the problems begin, because from the onset of infection to the appearance of the first signs of the disease, about a week usually passes, which means that during this period the carrier could infect other people, who will also have no symptoms for 7-9 days.

For this reason, in large children's groups, when a case of streptoderma is detected, a quarantine is prescribed, which lasts about 10 days. During this period, all infected people already have symptoms of the disease, and children do not attend educational institutions or swimming pools until they have fully recovered. It is advisable to limit the presence of the patient, as well as those who care for him, in any public places, so as not to contribute to the spread of infection.

How contagious is streptoderma? Based on the fact that the infection has external manifestations, having the possibility of transmission by contact and contact-household means, doctors believe that a person remains contagious from the moment of infection until the disappearance of characteristic signs of the disease (with treatment, symptoms go away in 3-14 days). The disappearance of external symptoms indicates the suppression of the infection, i.e. a noticeable decrease in its activity and the death of most microbial particles. Low-active surviving individuals remain relatively safe inhabitants of the skin and mucous membranes and do not pose a danger to others.

But we have already noted that in people with weak immunity and chronic diseases, streptoderma can last a long time with periods of remission and exacerbation of the disease. During the latent course, such patients are considered non-infectious, but when acute symptoms appear, they again become dangerous to others. Such a person becomes a constant source of infection for relatives and friends.

Having studied the pathogenesis and causes of streptoderma, we can come to the conclusion that even the opportunistic microorganisms that are familiar to us, our close and seemingly quite safe "neighbors" under certain conditions can turn out to be the worst enemies, capable of causing more or less serious health problems for a person. Humanity does not yet know how to peacefully coexist with bacteria, except for maintaining a strong immune system that does not allow microbes to multiply on the surface and inside the body. This means that it is not yet time to relax and stop monitoring your health.