First let’s learn about asthma, what desensitization is and why children with asthma need it.
1. The dangers of asthma for children
The incidence of allergic diseases has increased significantly in the past few decades, and the incidence of asthma is also increasing year by year, and allergic asthma mostly develops in childhood, and about 30%-50% of children with the disease will continue into adulthood, and recurrent asthma attacks can seriously affect the life, study and work of children and parents, and endanger the physical and mental health of patients. For example, it can lead to growth and developmental disorders, and gradually develop into chronic obstructive pulmonary disease or pulmonary heart disease.
2. What is desensitization therapy?
The term “specific immunotherapy” is used for allergic reactions caused by inhalant allergens, mainly for IgE-mediated type I allergic diseases. After finding the main allergen (e.g. dust mite), the allergen protein is made into a vaccine, which is administered to the patient in low to high doses, causing a decrease in sensitivity (immune tolerance) to the allergen (dust mite), so that the child will not have allergic symptoms or will have significantly reduced symptoms when exposed to the allergen (dust mite) in the future.
3. Why do children with asthma need desensitization therapy?
Asthma is a common allergic disease that is difficult to treat clinically and has recurrent attacks. “The Global Initiative for the Prevention of Asthma (GINA) emphasizes the importance of desensitization in asthma treatment and stresses that a “symptomatic plus cause-specific” treatment plan is the fundamental solution for asthma patients to get rid of the disease and is the only way to change the natural course of allergic asthma and allergic rhinitis. It is the only treatment that can change the natural course of allergic asthma and allergic rhinitis, and is the only treatment recommended by the World Health Organization and the global societies for allergic reactions, asthma and immunology to treat the cause of allergic diseases and possibly cure them completely.
Which children are suitable for desensitization treatment?
Children with mild to moderate allergic asthma, allergic rhinitis, and allergic conjunctivitis can be desensitized if the inhalant allergens are clear and difficult to avoid effectively (e.g., pollen, dust mites); children with eczema who have combined allergic rhinitis or asthma can also be desensitized. Clinical observations have shown that such patients have improved respiratory symptoms along with significant improvement in skin allergy symptoms. Uncontrolled moderate to severe asthma requires aggressive symptomatic treatment. It is recommended to start desensitization after 1-3 months of asthma control, along with asthma control medications such as inhaled hormones and/or bronchodilators.
Why is desensitization not recommended for some children with asthma?
In children with moderate to severe asthma, desensitization is not recommended if FEV1 is still ≦70% of the expected value after adequate medication, suggesting that the airways have been irreversibly damaged. Desensitization to dust mites is not recommended for asthma patients with more than 3 completely unrelated allergens or allergens that are difficult to identify, or where dust mites are not the primary allergen. Other conditions that make desensitization inappropriate include: combined immune system disorders (immunodeficiency, autoimmune diseases, etc.); inflammation and fever, severe acute or chronic disease (including malignant disease, active tuberculosis); severe cardiovascular insufficiency; irreversible lesions of the reactive organs (emphysema, bronchiectasis, etc.); local or systemic use of beta-blockers (in case of systemic allergic reactions, such patients cannot be resuscitated with epinephrine); patients with poor compliance; and patients with a history of anaphylaxis. At present, food allergy-induced asthma cannot be desensitized and is only in the early stages of animal experiments or clinical trials, and clinical avoidance of allergic foods is strictly required.
What do children with asthma need to do before desensitization?
First of all, go to a specialized children’s hospital and see an allergist or respiratory physician to clarify whether it is allergic asthma? What are the allergens? Is it an indication for desensitization? Which desensitization method is better to choose? What medications are also needed to complement the desensitization treatment? A professional doctor will develop a treatment plan for your child that is appropriate for your child. Desensitizing medications are not over-the-counter (OTC), and some children actually cannot be desensitized, may not need desensitization, or may not be suitable for immediate desensitization at this time. Blind desensitization may make the condition worse, so remember to always seek a professional doctor.
Methods of desensitization treatment
The main and most prevalent inhaled allergens for allergic diseases in China are house dust mites and dust mites, and the standardized desensitization treatment available in China at present is mainly for dust mite desensitization. The methods that are commonly used and have positive efficacy are: subcutaneous injection or sublingual administration. The total course of subcutaneous desensitization is 3 years and the cost is 6000 RMB/year. The total course of sublingual desensitization is also 3 years, and the cost is $3,000/year.
1.Choose subcutaneous desensitization or sublingual desensitization?
Efficacy: Analysis of clinical data shows that the efficacy of subcutaneous desensitization is better than sublingual desensitization, with an efficiency of 75-85% for dust mites and a reported efficiency of 50% for sublingual desensitization. Moreover, subcutaneous desensitization can prevent new allergies and disease progression. Safety: sublingual desensitization is safer (because the sublingual mucosa does not contain mast cells, the risk of serious allergic reactions is low); sublingual desensitization is easy to use and can be done at home; and sublingual desensitization is inexpensive, half the price of subcutaneous desensitization. Compliance: Children with sublingual desensitization may have poor compliance because parents may often forget to give the medication to their children, or ask their children to give the medication themselves, or ask their grandparents’ generation or teachers to give the medication, resulting in the wrong dose, which is potentially very dangerous. It is recommended that parents evaluate the above aspects and then discuss with the specialist to adopt a more suitable desensitization method for their child.
2. What is the best age for desensitization treatment?
Children’s immune system is not yet well developed and is very plastic. The earlier the allergic disease is treated, the better, and the more effective the desensitization treatment will be. The current recommended age for sublingual desensitization is 4 years or older, and the current recommended age for subcutaneous injection desensitization is 5 years or older. Successful desensitization can prevent the development of new allergies and the further progression of allergic rhinitis to allergic asthma. After regular desensitization treatment, children with allergic asthma can significantly reduce or even eliminate wheezing and shortness of breath, and the efficacy will be maintained for a considerable period of time, even for a lifetime, even after the course of treatment.
3.Does desensitization affect growth and development? Does it contain hormones?
No. Subcutaneous desensitization therapy has been carried out for more than 100 years (since 1911), and sublingual therapy has been carried out in Europe for more than 20 years, and there are no reports of “affecting growth and development”. Hormone-free. Desensitizing drugs are standardized water-soluble vaccines that need to be stored in a 0-8°C refrigerator. For example, “dust mite desensitization vaccine” is only dust mite extract.
4.Subcutaneous desensitization
At present, the main products used are the German Aroger double mite preparation (house dust mite and dust mite) and the Danish Androda house dust mite preparation. The whole course of treatment is divided into an initial treatment phase and a maintenance treatment phase. In the case of Aroger, for example, the interval between injections in the initial treatment phase is 1-2 weeks (4 months in total), the concentration increases from concentration level 1 to level 3, and the dose increases from 0.05 ml, 0.1 ml, 0.2 ml…0.8 ml each time. After the initial treatment reaches a concentration of 1.0ml at level 3, maintenance treatment is administered until the end of the course of treatment, with the maximum dose tolerated by the patient at level 3, and the interval between injections in the maintenance phase is 4-6 weeks. (until the end of the course of treatment).
What happens if subcutaneous desensitization is interrupted for any reason?
If the interval between injections during the initial treatment is too long, a dose adjustment is required, e.g., more than 2 weeks, the dose is adjusted to 50% of the last injected dose; more than 4 weeks, a restart is required. If the interval between injections during maintenance treatment is too long, the dose should be adjusted accordingly, e.g. over 6 weeks, the dose should be adjusted to 50% of the last injection dose; over 8 weeks, to 5% of the last injection dose; over 52 weeks, the desensitization should be restarted.
Notes for patients with subcutaneous desensitization
(1) Subcutaneous desensitization treatment should be performed in a hospital with monitoring by a health care professional.
(2) They should stay in the hospital for at least 30 minutes after the injection for observation and be accompanied by a parent throughout.
(3) Physical activity and hot baths should be avoided on the day of injection.
(4) Avoid overexertion the day before the injection.
(5) Peak flow rate should be measured before and after the injection.
(6) If there is acute infection, fever, or acute asthma attack on the day of injection, it should be suspended and treated symptomatically.
(7) One week interval from other immunizations.
(8) Maintain good communication and interaction with the doctor, and adjust the treatment plan according to medical advice if there is any interruption of treatment or adverse reaction.
5.Sublingual desensitization
What if sublingual desensitization is interrupted for any reason?
In the initial phase, it is recommended to restart when the drug is stopped. In the maintenance phase, stop taking the drug for more than 2 weeks (maximum 4 weeks), reduce 3 levels or start from the smallest dose and then gradually increase; stop taking the drug for more than 4 weeks, when taking it again, it should start from the smallest dose.
What should I do if I have adverse reactions to sublingual desensitization?
Common symptoms of adverse reactions include: slight numbness or scratching sensation in the mouth and tongue; local rash; mild diarrhea; fatigue. The degree of tolerance to allergens varies greatly from patient to patient, and intolerance usually occurs in increasing concentrations. Treatment of adverse reactions: The majority of patients with mild intolerance do not need to be treated and can subside on their own within a week. For patients with allergic symptoms aggravated by intolerance (allergic rhinitis, mild asthma attacks), symptomatic medication or dose adjustment (dose reduction) can be used.
Notes for patients with sublingual desensitization
(1) Use the medication strictly in accordance with the stated dose and do not increase or decrease the dose at will.
(2) If there is a slight overdose (for example, parents give 4 or 5 drops when there should be 3 drops of No. 4), there is no need to be overly alarmed, drink more water and take anti-allergy medication at the same time, most of which can be relieved on their own.
(3) Maintain good communication and interaction with the doctor, patients with serious adverse reactions should determine with the doctor whether to continue desensitization.
(4) Patients with acute infections, fever, or acute attacks of asthma may suspend or reduce the dosage of medication for one week.
(5) Suspension of sublingual desensitization on the day of and the day after prophylaxis.
(6) Where there is an adverse reaction within 24 hours after taking, the dose of the next day should be reduced by 3 levels (if during the increment, the dose of the next day to the minimum dose), and then gradually incremented after tolerated.
6.Can subcutaneous injection desensitization and sublingual desensitization be converted to each other?
Yes. If you want to switch to sublingual desensitization during the initial treatment period of subcutaneous injection, you should start from the beginning; if the child has already entered the maintenance period, you can start directly from Changdi 4 3 drops. If intolerance to sublingual dosing occurs in patients who have started in the maintenance phase, treatment should still be started with No. 1 1 drop. To switch to subcutaneous injection, regardless of whether the sublingual child is in the initial treatment phase or the maintenance phase, it is necessary to start from the beginning.
Effectiveness of desensitization therapy
(1) The keys to successful desensitization therapy are: environmental control, avoiding exposure to dust mite allergens as much as possible; adherence to standardized medication with an adequate course of treatment; and the combination of symptomatic drugs.
(2) Early effect: the effect appears 4-5 months after desensitization treatment.
(3) Continuous effect: the effect always exists during 3 years of desensitization treatment.
(4) Long-term effects: effects that persist after the course of desensitization treatment (up to 15 years of follow-up).
(5) Preventive effect: prevention of the occurrence of new allergies and exacerbation of the disease.