House dust mite - small creature, huge threat
House dust mites are invisible to the naked eye creatures that feed on the scales of human and animal skin. They are the most common cause of allergy in Poland [1]. The most important mite species from an allergologist’s point of view is Dermatophagoides pteronyssinus. Arachnids belonging to this species are one of the main sources of mite proteins that cause numerous allergic complaints. These microorganisms live in homes and settle in mattresses, duvets or carpets [1]. Due to their constant presence in our homes, mites can cause allergies in patients throughout the whole year.
Symptoms of mite allergy
House dust mite allergy affects between 65 to 135 million people worldwide [2].
Patients with dust mite allergy usually suffer from respiratory symptoms. Contact with house dust mites occurs through inhaling air with their particles. This is because when we breathe, we introduce the allergens into the nasal cavity. This is where the first symptoms known as allergic rhinitis occur. They are characterised by sneezing, a watery nose, coughing and itching of the nasal or eye area [3].
In more severe cases, however, asthma can develop. People with this condition must take appropriate medication and be under medical supervision. The most common symptom of asthma is a cough that occurs during the day or night. Other symptoms of mite-sensitive allergy sufferers include difficulty breathing, as well as chest pain. In addition, wheezing or problems with exercise tolerance may also occur [4]. Asthma symptoms are exacerbated after contact with allergens or during infections. In addition, physical activity, smoking or other pollution may also contribute to exacerbating the symptoms of allergic reactions [4].
Some may also struggle with symptoms as a result of direct skin contact with an allergen. An example of this is atopic dermatitis. This is characterised by severe itching or dryness of the epidermis. In the case of AD, reddish-pink lesions appear on the body, which may then flake off. They are most often localised around the bend of the elbows or knees, as well as on the face or neck. [5]
In the case of mite allergy, patients note characteristic circumstances for the appearance of symptoms. Some report the onset of discomfort during cleaning, others mention an increase in symptoms at night. Additionally, mite-sensitive allergy patients are much more likely to suffer from allergic reactions in the autumn. This is because we ventilate our homes less and the heating season begins at that time.
Der p 23 - essential allergen
To this day, 38 allergens of the house dust mite species Dermatophagoides pteronyssinus have been identified. In addition to Der p 1 and 2, the recently discovered protein Der p 23 also plays a key role in causing allergic reactions. Der p 23 is a marker for primary sensitisation to house dust mites. This means that it contributes to the development of primary allergy, not arising from cross-reactions with other allergens. Der p 23 is recognised as the main allergen associated with the mite. Research indicates that up to 74% of patients affected by house dust mite allergy are allergic to Der p 23 protein [6]. Importantly, about 8% of these patients show sensitisation only to this particular protein [7]. Therefore, it is important to use precise laboratory tests, such as molecular diagnostics of allergy, to detect sensitisation to a specific protein.
Furthermore, recent studies show that sensitisation to Der p 23 is associated with more severe allergy symptoms [8]. Analysis has also shown that children sensitised to this protein are more likely to suffer from asthma, allergic rhinitis and atopic dermatitis [9]. These observations indicate that sensitisation to Der p 23 may provide important information about the possible course of the disease.
It is worth noting that exposure to this allergen occurs mainly through inhalation of air containing the mite. In addition, Der p 23 often cross-reacts with proteins of another mite species, Dermatophagoides farinae.
Methods for diagnosing house dust mite allergy
If you have noticed that you are struggling with dust allergy symptoms, consult your doctor. In order to find the cause of your symptoms, the specialist will carry out a medical interview and allergy tests. A modern and effective method is molecular allergy diagnostics. This advanced test makes it possible to determine precisely which specific protein the patient is allergic to. It also helps answer the question of whether Der p 23 is the cause of allergic symptoms [10].
It is worth noting that the test results are a helpful tool for the doctor. They make it easier to determine the course of the disease. The information received also allows an individual adjustment of the treatment. This is crucial for effective control of dust allergy symptoms and an improvement in the quality of patients’ lives.
Treatment of dust mite allergy
When mild dust allergy symptoms appear, such as itching, sneezing or watery nasal discharge, pharmacological treatment in the form of antihistamines should be applied. In contrast, people with asthma require daily medication to control the course of the disease. When an asthma exacerbation occurs, bronchodilators should be used to stop the attack. This form of treatment focuses on relieving the symptoms.
In the case of sensitisation to major proteins such as Der p 1 or Der p 2, the doctor may consider a causal allergy treatment method of immunotherapy, commonly known as desensitisation. This method of treatment involves repeated administration of small doses of an allergen. Its aim is to build up the body’s tolerance to that particular allergenic protein. The duration of treatment is quite long, ranging from 3 to 5 years. Although immunotherapy has been shown to be effective in cases of sensitisation to Der p 1 and Der p 2, for patients sensitised only to Der p 23, it may not be successful [11]. The problem is that this protein is absent or insufficient in desensitisation formulations. Therefore, it is crucial to carry out a molecular diagnosis of the allergy and accurately identify the protein causing the allergic reactions. The test results should be discussed with an allergologist, who will select the appropriate treatment.
What do you need to know about mite allergy and Der p 23? Summary
Allergy to house dust mites is a common problem. Many people with this type of allergy struggle with symptoms of allergic rhinitis or asthma caused by, among other things, the Der p 23 protein. A correct diagnosis makes it possible to choose the right treatment, as well as the right prevention. By combining these methods, patients’ quality of life can be improved.
Weronika Gromek
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translation: Julia Majsiak
