How to correctly measure the reaction to the Mantoux vaccine in a child

The Mantoux test is used to measure the human body's immune response to tuberculin, a heat-treated, specially processed fragment of tuberculosis bacteria. Intradermal administration has been used for over 70 years worldwide. In adults, the test shows whether a person is infected with the tuberculosis bacillus or not. For children, the Mantoux test is used for a slightly different purpose.

The sample is injected into the top layer of skin by lifting the skin with a needle. Intradermal administration is used mainly for the forearm, for its middle part.

WHAT IS THE MANTOU REACTION

The Mantoux test is designed to provoke an immune response. It has nothing to do with vaccination, so it is incorrect to say that Mantoux is a vaccination. In order for the human body to respond to a microbiological invasion, the immune system must be familiar with these microorganisms. The immune system can only respond to threats with which it is already familiar. The immune system will not be able to recognize new infections until a person is vaccinated or has had a certain disease.

If the immune system is familiar with tuberculin bacteria, when they are introduced, immune cells will attack tuberculin. In this case, a local inflammatory reaction will be observed.

Mantoux in a child: on what day is the reaction checked, its result, how long does the trace last?

Usually, parents whose children have had a Mantoux test have questions about how long the Mantoux mark lasts, how to care for the injection site, and which of the symptoms that appear are considered normal. In order to understand this, you need to know the mechanism of action of the tuberculin test.

The Mantoux reaction is a kind of test of the immunological reaction of the human body, not the subcutaneous injection of an extract from Koch’s bacillus. Leukocytes that have ever been “familiar” with tuberculosis are attracted to the place where the injection was given, which is why the papule begins to redden and swell.

The baby is tested for the first time at 12 months and is subsequently repeated annually. The results obtained after testing are carefully recorded in the child’s medical record and are important for monitoring his health. The doctor pays special attention to the size of the papule and the length of time during which the brown spot persists after Mantoux.

After the child is given the test, it is necessary to carefully monitor its condition and changes:

1. Papule growth of up to 0.2 cm is the absolute norm and should not cause concern.
2. The diameter of the injection mark from 2 to 4 mm is also considered a normal reaction of the body, but requires consultation with a phthisiatrician.
3. Button sizes from 5 to 16 millimeters are a positive reaction. In this case, the child is sent to a TB specialist for a more thorough examination.
4. The size of an injection mark of more than 17 millimeters in the vast majority of cases indicates the presence of a significant number of Koch bacilli in the body and possible infection.

How many days does it take for the Mantoux spot to go away? This question worries many parents. The button appears most actively on the third day after the injection, which is why the test result is read at this time. After this, the trace of the sample begins to gradually disappear. Normally, a Mantoux stain does not go away for a week, and then gradually fades and not a trace remains of it.

It should be remembered that when answering the question: “When will the trace of Mantoux disappear?”, it is necessary to take into account the individual characteristics of each organism. In some children, the spot from the test may disappear after 2-3 days. For other guys, redness or a brown mark may remain for as long as a week or even more and only go away completely after a month. If the child feels well and the injection spot continues to gradually heal, then there is no need to worry and there is no point in seeing a doctor.

The duration of how long the mark from the tuberculin test will last is also influenced by the recently administered BCG vaccination, which is given in order to create immunity in a person to the tuberculosis bacillus. If the Mantoux test is performed soon after BCG, the papule will be enlarged and red in color. In this case, the child does not pass the Mantoux point for a very long time.

In the vast majority of children, the papule reaches a size of 0.4 centimeters on the third day after the injection and disappears completely over time. If there is a stain left after Mantoux, then you should know that, due to physiological characteristics, in some people it may remain for the rest of their lives.

If a baby has this type of reaction, it can be triggered by various factors:

• heredity;
• excessive saturation of the body with protein enzymes.

Nevertheless, children whose stain from the tuberculin test does not disappear for too long are registered with a TB doctor, since the risk of developing the disease is quite high among them. Their health status must be constantly monitored.

Another reason why the “button” cannot heal may be an allergic reaction to the components of the injected drug. In this case, you need to have one of the histamine medications on hand that can suppress allergy symptoms. In the future, it is recommended to consult an allergist. Sometimes in the photo you can see that an allergy to a drug gives a pronounced false-positive result.

If, five days after the injection was given, the child’s spot from it does not disappear or, moreover, the papule has greatly enlarged, turned red and began to fester, this may indicate the following:

1. The presence of Koch bacilli in the body in active form.
2. Individual intolerance to the administered drug.
3. Violation of injection rules and development of sepsis.

In addition, the papule may not go away for a long time if the rules for handling the injection site were violated or if the injection was given without taking into account existing contraindications.

WHY DO THEY MAKE MANTU FOR CHILDREN?

There are several purposes for testing in childhood:

• Identification of uninfected patients for subsequent vaccination. Using a test, you can find out whether there is a response to tuberculin.
• Checking the dynamics of test results over several years. Using this information, one can determine the Mantoux “turn”, the presence of tuberculosis with a high degree of probability.
• Determination of a severe reaction that requires additional research.

In adult patients, the test is a reliable, sensitive test for determining the presence of the tuberculosis pathogen in the body.

Children begin testing at age 1 and finish testing at age 15. Mantoux is administered annually.

Possible results

The sizes of Mantoux in children vary greatly. This is influenced by many factors. To more accurately assess the picture, additional examinations are carried out.

Negative

A normal Mantoux reaction should show a negative result. Such indicators indicate that the body has either not yet encountered pathogens or has already overcome them. In such a situation, revaccination is carried out. Visually, there is a complete lack of reaction to the administered substances. There is no compaction or redness at the injection site.

Doubtful

The result is considered doubtful if there is no compaction. At the injection site there is only redness, the size of which is also of great importance. If the Mantoux test result is within 2-4 millimeters, Koch's bacillus is not present in the body.

Positive

The result of the reaction depends on what Mantoux looks like for tuberculosis. Possible reactions:

• mild (5-9 mm);
• medium (10-14 mm);
• pronounced (15-16 mm);
• excessive (more than 17 mm).

This indicates the body’s fight against the disease.

Hyperergic

Severe inflammation is observed, the size of the compaction reaches 17 mm, and the lymph nodes are enlarged. The presence of a pathogen in the body is expressed in the following symptoms:

• the injection site becomes rich red;
• the papule has clear boundaries;
• a week after Mantoux vaccination, the infiltrate darkens;
• a red stripe runs from the papule to the elbow;
• suppuration is observed.

If such signs appear, you should consult a doctor, but such symptoms do not prove the presence of infection.

False positive

This reaction occurs in the following cases:

• contact with an infected person;
• the presence of non-tuberculous mycobacteria in the body;
• recently vaccinated:
• the immune system has already encountered the pathogen;
• the person has recently suffered from an infectious disease.

In this case, redness without compaction is observed, not exceeding 4 mm in size.

False negative

This condition is characterized by the complete absence of an allergic reaction. The papule is not visible, or its size does not exceed 1 mm. Causes:

1. Using a low-quality drug.
2. Violation of the rules for administering the solution.
3. The disease is in the incubation stage.

An additional diagnosis is prescribed to clarify the clinical picture.

Turn and blister effect

A turn is usually called a reaction result that is much greater than the values ​​of the previous procedure. This includes:

• transition from a negative or questionable sample to a positive one without vaccination;
• an increase in papule by 6 mm over 1 year in vaccinated babies;
• maintaining the value within 12 mm for 3 or more years;
• the presence of a hyperergic reaction regardless of the time of vaccination.

If there is a blister effect, doctors suspect the patient has tuberculosis. For an accurate diagnosis, a referral to a dispensary is issued.

COMPOSITION OF THE PREPARATION

To perform testing, tuberculin tests are used, consisting of:

• Chemically, thermally treated fragments of bacteria.
• Twin-80 – stabilizer.
• Phenol is a preservative.
• Potassium and sodium phosphates.
• Sodium chloride.
• Water.

As a rule, many parents are frightened by the presence of phenol in the composition of the drug. Yes, it is a toxin, but its presence in the sample is minimal. Therefore, there is no harm to health. Low concentrations of the substance in medical preparations are justified for use.

NORMAL FOR CHILDREN

After the first BCG vaccination, children retain anti-tuberculosis immunity for up to 7 years. How well it is preserved depends on the diameter of the scar after the test. It remains on the left shoulder. If there is no such round mark, this means that the BCG vaccination was not given, and the child does not have immune protection against tuberculosis.

Table 1. Preservation of anti-tuberculosis immunity after BCG vaccination depending on the diameter of the post-vaccination scar.

The age of the patient decides what the reaction to the test should be:

• 1 year. The papule is 5-10 mm in size, regardless of the size of the post-vaccination scar.
• 2-6 years. The intensity of anti-tuberculosis immunity reaches its maximum by the age of 2 years. If the scar is larger than 8 mm, the papule can reach 16 mm. After 3 years, the immune response dies down. However, at 4-5 years old, children still have a positive or questionable reaction, and the size of the papule at the age of 4-6 years is considered normal if it does not exceed 10 mm.
• 6-7 years. At this age, patients have a negative or questionable response to the test. A negative result is a signal about the need for re-vaccination. Routine revaccination is performed at 7 years of age.

7-14 years old. As after the first vaccination, the intensity of immunity remains in the first 3 years, and then begins to subside. Therefore, the response to injected tuberculin fades by the age of 10 years. By the age of 13-14, patients have a negative, questionable response to the test.

Table 2. Correlation between the normal size of the papule and the size of the post-vaccination scar in children aged 3-5 years.

Nature and process of grafting

The test is administered by injecting a disposable syringe shallowly under the skin from the palm to the elbow from the inside on the surface of the child’s arm. Typically, such an injection is not too painful, so you need to talk to a child of a conscious age in advance so that he does not feel afraid of the vaccination.

After some time, a papule forms at the puncture site. After 72 hours, its diameter is measured with a ruler, and the obtained figures are used to determine the state of immunity and the activity of Koch’s bacillus in the body.

In order for the doctor to make a correct diagnosis, it is necessary to take certain precautions after the injection.

The injection site must be protected so that the size of the mantoux is true. Under no circumstances should it be wet. Therefore, showers and baths are canceled while waiting for the Mantoux reaction in a one-year-old child. You can wash your face, wash your legs and other parts of the body, but you need to be careful not to let water get into the grafting site.

You also need to avoid dirt and dust, so vigorous games in the sandbox are canceled for three days.

You should not scratch the papule or the area around it; you should avoid playing with pets so that their claws, tongue and fur do not get dirt into the skin puncture site. During these three days, until the doctor measures the red spot that represents the reaction, you need to take care of the child.

You should also not eat red vegetables and fruits, so as not to cause excessive redness, but you should not change your diet too much, so that this does not become a shock to the body and cause an unusual reaction to the vaccine.

Somewhere during the month when the vaccination should occur, there is no need to change the baby’s usual menu much. You just have to limit meat and dairy products a little. The rest of the menu should be in its normal state without sudden changes. Also, you should not put a band-aid on the injection site or apply anything on it.

If water accidentally gets on the papule, you need to honestly tell the doctor about it. If the red spot is large enough, the doctor may send you to a tuberculosis clinic for additional tests. To prevent this from happening, you must warn the doctor that it was not possible to protect the injection site. And then he will calculate the body’s reaction based on the diameter of the spot, taking into account the ingress of water.

After the doctor has examined, measured the spot and made conclusions, you can lubricate the hole from the injection with brilliant green, wait a little until it heals and then continue to lead a normal life for the baby. The Mantoux vaccination will not seriously affect his health.

REACTION TO TEST BY DAY

A reaction to Mantoux is observed in patients on the second day after the test. The body may react with the formation of a papule and/or redness. The maximum immune response can most often be noted on the third day. The reaction can be negative, false negative or positive, false positive:

• Negative. The absence of any reaction indicates that the immune system is not familiar with tuberculosis pathogens. The patient does not suffer from tuberculosis in any form. If a child has had less than 5 years since vaccination, a negative reaction is a bad signal. He reports that the immune system does not remember danger. If more than 5 years have passed, then the lack of reaction is a plus. This is a sign that the child is not sick. The same rule works for adults.
• False negative. This reaction can be observed in cases where a person’s immune system stops responding to injected tuberculin over the years.
• Positive. We can talk about such a reaction to the test if the papule is larger than 5 mm in diameter. It is necessary to analyze a positive result in children based on a combination of factors. It is necessary to evaluate the dynamics of the sample over the past years, the very nature of the papule, the size of the scar, and how long ago the vaccination was performed. If the reaction is positive in an adult, this is a signal of almost 100% probability of infection.
• False positive. This category includes questionable answers - redness of any size, papules with a diameter of less than 4 mm. A false positive reaction can occur in a number of cases. For example, when a person has recently undergone any vaccination or has had an infectious disease. Also, a questionable reaction occurs with a skin allergic reaction, etc. To make sure that there is no need to panic in case of a false positive result, it is necessary to check whether the patient has contacts with tuberculosis patients, the situation in the region, and whether the incidence threshold has been exceeded.

When to check Mantoux

The Mantoux reaction, although not a vaccination in the full sense of the word, is included in the list of mandatory vaccinations that a child must receive. For the first time, a tuberculin test is performed on one-year-old babies. If the procedure is performed earlier, due to possible skin reactions, it is difficult to determine the result.

Then the Mantoux reaction is checked every year at approximately the same time until the child turns 14 years old. Children who have not been vaccinated against tuberculosis are given a Mantoux test twice a year. And for children who are at risk, i.e., who have close contact with a person with tuberculosis, the Mantoux reaction is checked 2-4 times a year. The Mantoux reaction is checked after a few days by doctors.

After tuberculin is injected intradermally into the child, bacterial particles begin to attract T-lymphocytes. Thus, T-lymphocytes that have already dealt with Koch’s bacillus react to the introduction of the substance. This is the Mantoux reaction, which externally looks like a compaction, a “button” on the inner surface of the forearm. It must be of a certain size and shape; if there are deviations, the doctor may suspect tuberculosis in the child. In order not to sound the alarm ahead of time, scaring yourself and your child, it is important to know after how many days Mantoux is checked. During the first days, the injection site may become red and inflamed, and may be too swollen, making examination difficult.

The substance tuberculin itself, which is used to test, is not capable of causing tuberculosis. It consists of weakened tuberculosis pathogens and is not dangerous to humans.

SIDE EFFECTS, COMPLICATIONS

An excessive response of the patient’s body to the administered drug is the cause of the main side effects. These include:

• Allergy. This reaction is possible in patients of any age, since tuberculin is an allergen.
• Temperature. With high sensitivity to the drug, a slight increase in temperature may be observed.
• Hyperergic reaction. Formation of papules larger than 17 mm in diameter. This answer indicates the presence of tuberculosis infection in the body.
• Cough. Traditionally, this side effect is not associated with the administration of the sample.
• The papule itches. It is necessary to avoid scratching the papule; the tuberculin injection site itself may itch.

Adverse reactions

The reaction after Mantoux in children may manifest itself as the following symptoms:

1. Fever and chills. Worsening of health is observed in the evening after the injection or the next morning. The temperature rises slightly (up to 37.5-38°C). Sometimes nausea and dizziness occur. As the temperature normalizes, the child's condition improves.
2. Skin rashes and itching. Redness can appear on any part of the body. Some children experience swelling of the face and mucous membranes of the nasopharynx. The phenol contained in the injection sometimes causes allergies. If the patient is intolerant to some components of the sample, alternative drugs are prescribed. To treat the rash, you can use Dimexin ointment.
3. Decreased appetite, pain in the abdominal area. Severe diarrhea may occur. In this case, the child should be given more fluid.
4. Lethargy and drowsiness.
5. Strong headache. Often this symptom is accompanied by a cough, runny nose and other signs of colds. It is recommended to give tea with honey to drink at night.
6. Nausea and vomiting.
7. Blue papule. When the injection was administered, the blood vessels were damaged.

If your health does not improve within 3 days, it is recommended to seek medical help.

ALTERNATIVE TO MANTOU SAMPLE

For those who want to avoid the Mantoux test, there is an alternative option. The Diaskintest test has proven itself because it is less likely to produce false positive results. However, it produces false negative reactions more often. As a rule, Mantu is used as a basic test, and Diaskin as a clarifying test.

The Mantoux test is used to test the body's response to tuberculosis bacteria - whether the immune system can fight them. This test can give a false positive result in 80% of cases. But the diagnosis is confirmed in no more than 1% of cases in children. For adults, Mantoux is the main, most accurate and sensitive method for detecting tuberculosis infection.