Study of Blomia tropicalis allergen extract skin prick test compared to histamine in patients allergic to Blomia tropicalis mites

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What is this study about?

This clinical trial focuses on studying allergies specifically related to Blomia tropicalis, a type of house dust mite that can cause allergic reactions. The study will use a skin prick test with different solutions: an extract made from Blomia tropicalis, a positive control containing histamine dihydrochloride, and a negative control containing sodium chloride (salt solution).

The purpose of this study is to determine what concentration of Blomia tropicalis extract creates a skin reaction equal in size to the reaction caused by a standard histamine solution. During the study, small amounts of these solutions will be applied to the skin through tiny pricks to measure the body’s allergic response. The skin’s reaction appears as a raised bump called a wheal.

The study involves a single visit where participants receive several skin prick tests with different concentrations of the allergen extract and control solutions. All solutions are applied to the skin surface only. The study will monitor any side effects that might occur during or after the testing procedure.

1 Initial skin testing

A skin prick test will be performed using three different solutions:

– A negative control solution containing sodium chloride

– A positive control solution containing histamine dihydrochloride

– Three different concentrations of Blomia tropicalis extract (a type of dust mite)

2 Skin reaction measurement

The medical staff will measure the size of any skin reactions (called wheals) that appear after the skin prick test

The measurement will focus on the area of the skin reaction in square millimeters

A positive reaction is indicated by a raised bump measuring 3 millimeters or more in diameter

3 Monitoring period

You will be monitored for any reactions at the test site

Medical staff will document any immediate or delayed skin reactions

Any side effects or adverse reactions will be recorded

If needed, appropriate treatment will be provided for any adverse reactions

4 Follow-up assessment

The test site will be examined for any lasting reactions

Any medications needed to treat reactions will be documented

The study will evaluate both local skin reactions and any systemic (whole-body) responses

5 Study completion

The total duration of your participation will be brief, limited to the time needed for testing and observation

Female participants must continue using effective birth control for 72 hours after the test

Who Can Join the Study?

Age between 18 to 64 years old, male or female
Must sign and date an informed consent form
Must live in an area where Blomia tropicalis (a type of house dust mite) allergies are common
Must have a history of breathing-related allergies (such as runny nose, itchy eyes, or breathing difficulties) caused by Blomia tropicalis
Must have a positive skin prick test (showing a raised bump ≥ 3 mm) or presence of specific allergy antibodies (IgE) to Blomia tropicalis
Must show a specific skin reaction to histamine (a substance used to test allergic response): raised bump area ≥ 7 mm²
Must show minimal reaction to the negative control test: raised bump area < 7 mm²
Women who can become pregnant must:
- Have a negative pregnancy test when joining the study
- Have had a recent menstrual period
- Use effective birth control during the study and for 72 hours after
Acceptable birth control methods include:
- Hormonal contraceptives (pills, patches, vaginal rings)
- Intrauterine devices (IUD)
- Hormone-releasing implants
- Having a partner who has had a vasectomy
- Complete sexual abstinence

Who Cannot Join the Study?

Age below 18 years or above 65 years
Pregnancy or breastfeeding
Currently having severe allergic symptoms or anaphylaxis (a serious, life-threatening allergic reaction)
Taking antihistamine medications within the past 7 days
Having severe skin conditions that could interfere with skin testing
Current use of medications that could affect the test results, such as steroids
History of severe reactions to skin testing
Unstable medical conditions like severe asthma or heart problems
Unable to stop medications that might interfere with allergy testing
Having a skin condition that could make it difficult to read skin test results
Recent severe allergic reaction within the past month
Current fever or active infection
Having received allergy shots (immunotherapy) in the past 6 months
Participation in another clinical trial within the past 30 days

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

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Other Sites

Site Name	City	Country	Status
Hospital Universitario De Canarias	La Laguna	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not recruiting	01.09.2025

Trial locations

Investigated Drugs:

Blomia tropicalis allergen extract is a substance derived from house dust mites that is used to diagnose allergies. When applied to the skin during a prick test, it helps determine if a person is allergic to this specific type of mite. The extract causes a small raised bump (wheal) on the skin in people who are allergic to it.

Histamine dihydrochloride is a reference substance used in allergy testing. It serves as a control substance during skin prick tests to compare the body’s reaction to the allergen. When applied to the skin, it creates a standard reaction that helps doctors measure how strongly a person reacts to the allergen being tested.

Blomia Tropicalis Allergy – A type of allergy caused by sensitivity to microscopic house dust mites known as Blomia tropicalis, which are commonly found in tropical and subtropical regions. This allergy typically manifests through respiratory symptoms when a person inhales particles from these mites. The allergic reaction occurs when the immune system overreacts to proteins found in the mite’s body and waste. Symptoms can include sneezing, runny nose, nasal congestion, and itchy eyes. This condition is particularly common in areas with high humidity and warm temperatures where these mites thrive.

Trial ID:

2024-515169-33-00

Protocol code:

M608-STD-067

Trial Phase:

Therapeutic exploratory (Phase II)

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Study of Blomia tropicalis allergen extract skin prick test compared to histamine in patients allergic to Blomia tropicalis mites

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?