This site is intended for UK healthcare professionals
Medscape UK Univadis Logo
Medscape UK Univadis Logo

Allergen extracts house dust mite oral

Updated 2 Feb 2023 | Allergen Immunotherapy


Oral lyophilisate formulation of house dust mite standardised allergen extract.

Drugs List

  • ACARIZAX 12 SQ-HDM oral lyophilisate tablet
  • house dust mites allergen extract 12 SQ-HDM oral lyophilisates sugar-free
  • Therapeutic Indications


    Allergic asthma - house dust mite
    Allergic rhinitis - house dust mite

    Persistent moderate to severe house dust mite allergic rhinitis despite using medication to alleviate symptoms.

    House dust mite allergic asthma associated with mild to severe house dust mite allergic rhinitis when symptoms not controlled well by inhaled corticosteroids.



    One oral lyophilisate (12 SQ-HDM) daily up to 18 months.


    Children aged 12 to 18 years
    (See Dosage; Adult)

    Additional Dosage Information

    Contact a physician before resuming treatment if interruption occurs for more than 7 days.

    Taking anti-allergic medications concomitantly with house dust mite allergen extract may increase patient's tolerance level to immunotherapy. Therefore, this needs to be taken into consideration when discontinuing anti-allergic medications.


    Autoimmune disease
    Children under 12 years
    Acute respiratory infection in pre-existing asthma
    Acute severe oral inflammation
    FEV1 below 70% of predicted value at baseline
    Malignant neoplasm
    Oral wound
    Severe asthma

    Precautions and Warnings

    Children aged 12 to 18 years
    History of autoimmune disorder
    Patients over 65 years
    Cardiac disorder

    Not suitable for acute treatment of asthma
    Exclude gastrointestinal infection before commencing treatment
    First dose should be given under medical supervision: Risk of anaphylaxis
    Treatment to be initiated and supervised by a specialist
    Have adrenaline injection ready for use in case of anaphylaxis
    Monitor patient for 30 minutes after first administration
    Advise patient to report gastrointestinal signs or symptoms
    Advise patient to report if allergic reaction occurs
    Advise patient to seek medical advice if asthma seems to be worsening
    Consider antihistamines if severe local adverse reactions occur
    Discontinue if no improvement after treatment for one year
    Discontinue if serious allergic or anaphylactic reaction occurs
    Discontinue permanently if hypertensive crisis occurs
    Not licensed for all indications in all age groups
    Advise patient not to swallow for 1 min or eat/drink for 5 mins after use
    Advise patient to contact the doctor immediately in the event of a reaction

    House dust mite allergen extracts should be used initially as add on therapy, not a substitution of pre-existing asthma medication. It is not recommended to discontinue asthma medication abruptly after starting the treatment.

    Discontinue treatment and contact physician in case of severe systemic allergic reactions, severe asthma exacerbation, angioedema, difficulty swallowing and breathing, voice changes, hypotension or throat feeling full. The onset of systemic symptoms include flushing, pruritus, sense of heat, general discomfort and agitation/anxiety.

    Consider treatment carefully if patient previously experienced systemic allergic reaction to subcutaneous house dust mite immunotherapy due to increase risk of severe allergic reaction.

    Postpone treatment and interrupt ongoing treatment if patient experiences severe oral inflammation such as oral lichen planus, mouth ulcers or thrush, oral wounds, oral surgery, or tooth loss to allow healing of the oral cavity.

    Pregnancy and Lactation


    Use house dust mite allergen extracts with caution during pregnancy.

    The manufacturer does not recommend initiating treatment during pregnancy and use with caution if pregnancy occurs during treatment. At the time of writing, there is limited published information regarding the use of house dust mite allergen extracts during pregnancy. Animal studies indicate no increased risk of teratogenic or developmental effects however potential risks are unknown. If house dust mite allergen extracts is used during pregnancy, evaluate lung function and reaction to previous use to consider continuation of treatment during pregnancy. Close supervision of pre-existing asthma in pregnant patients is recommended.


    Use house dust mite allergen extracts with caution during breastfeeding.

    The manufacturer advises caution if house dust mite allergen extracts is used when breastfeeding. The presence of house dust mite allergen extracts in human breast milk is unknown. Effects on exposed infants are not anticipated.


    Immediately after opening, take with dry fingers from the blister unit. Dissolve the medicine under the tongue.

    Avoid swallowing within 1 minute and food and drinks for the next 5 minutes.

    Advise patient to seek medical advice if asthma appears to be worsening.

    Side Effects

    Abdominal pain
    Allergic conjunctivitis
    Allergic reaction
    Anaphylactic reaction
    Chest discomfort
    Dry mouth
    Ear discomfort
    Ear pruritus
    Exacerbation of pre-existing asthma
    Eye pruritus
    Gastroesophageal reflux disease
    Hypertensive crisis
    Laryngeal oedema
    Lip pain
    Lip pruritus
    Lip ulceration
    Mouth ulcers
    Nasal congestion
    Nasal discomfort
    Nasal obstruction
    Nasal oedema
    Oedema of the lips
    Oral discomfort
    Oral mucosal blistering
    Oral mucosal erythema
    Oral oedema
    Oral pain
    Oral paraesthesia
    Oral pruritus
    Oropharyngeal irritation
    Oropharyngeal pain
    Pharyngeal erythema
    Pharyngeal oedema
    Salivary gland enlargement
    Salivary hypersecretion
    Sensation of foreign body
    Taste disturbances
    Throat irritation
    Throat tightness
    Tongue oedema
    Tongue pruritus
    Tonsillar hypertrophy
    Tracheal oedema


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Reference Sources

    Summary of Product Characteristics: Acarizax 12 SQ-HDM. ALK-Abello Ltd. Revised May 2021.

    NICE Evidence Services Available at: Last accessed: 11 January 2022

    Access the full UK drug database with a FREE Medscape UK Account
    It takes just a few minutes, and you’ll get unlimited access to information on over 11,000 UK drugs.
    Register for Free

    Already a member? Log in

    Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content

    FDB Logo

    FDB Disclaimer : FDB Multilex is intended for the use of healthcare professionals and is provided on the basis that the healthcare professionals will retain FULL and SOLE responsibility for deciding what treatment to prescribe or dispense for any particular patient or circumstance.