Nasal provocation test

Nasal Provocation Test (NPT) is a diagnostic procedure used in allergology and otolaryngology to determine the sensitivity of the nasal mucosa to specific allergens. This test is particularly useful in the diagnosis of allergic rhinitis, a condition characterized by symptoms such as nasal congestion, sneezing, itching, and runny nose in response to allergens. The NPT involves the direct application of a suspected allergen into the nasal cavity to observe the body's reaction, thereby helping to identify specific triggers for an individual's nasal allergies.

Procedure

The Nasal Provocation Test is performed in a controlled clinical setting. The procedure involves several steps:

1. The patient's baseline nasal airflow is measured using rhinomanometry or acoustic rhinometry to assess the degree of nasal obstruction.
2. A diluted solution of the suspected allergen is carefully introduced into one nostril, while the other nostril receives a placebo solution.
3. After the administration of the allergen, the patient is monitored for symptoms such as sneezing, itching, and increased nasal secretion. Objective measurements of nasal airflow are repeated to detect any changes.
4. The response is evaluated based on both subjective symptoms reported by the patient and objective measurements of nasal obstruction.

Indications

Nasal Provocation Tests are indicated for patients with suspected allergic rhinitis when skin prick tests or specific IgE blood tests are inconclusive. It is also useful in identifying the causative allergens in patients with perennial allergic rhinitis, where environmental control is challenging.

Contraindications

There are several contraindications to performing a Nasal Provocation Test, including:

• Severe nasal or systemic allergic reactions in the past
• Uncontrolled asthma
• Recent nasal surgery
• Acute respiratory infections
• Pregnancy

Risks and Complications

While the NPT is generally safe, there are potential risks and complications, such as:

• Nasal discomfort or pain
• Induction of a severe nasal or systemic allergic reaction
• Epistaxis (nosebleed)

Interpretation of Results

A positive test result is indicated by a significant decrease in nasal airflow as measured by rhinomanometry or acoustic rhinometry, accompanied by typical allergic symptoms. A negative test suggests that the tested allergen is not a trigger for the patient's nasal symptoms.

Clinical Significance

The Nasal Provocation Test is a valuable tool in the diagnostic work-up of allergic rhinitis. It provides specific information about the allergens responsible for triggering symptoms, which is crucial for effective allergen avoidance strategies and targeted immunotherapy.