Patch testing is a non-invasive procedure that evaluates whether the skin develops an allergic reaction to specific substances.

Unlike prick testing used for environmental allergies, patch testing assesses delayed hypersensitivity reactions that occur over several days.

It is used to identify the cause of:

• Chronic or recurrent rashes
• Unexplained dermatitis
• Suspected reactions to products or environmental exposures

Patch testing is considered the gold standard for diagnosing allergic contact dermatitis.

Patch testing is recommended for patients who:

• Have persistent or recurrent rashes
• Experience dermatitis that does not respond to standard treatments
• Suspect a reaction to skincare, cosmetics, or personal care products
• Have occupational exposures that may trigger skin reactions

It is particularly helpful when the cause of a rash is unclear or when symptoms continue despite treatment.

Patch testing screens for a broad panel of common allergens.

These may include:

• Fragrances
• Preservatives
• Metals such as nickel
• Rubber and adhesives
• Ingredients in skincare and personal care products

In some cases, patients may also be tested with their own products to identify specific triggers.

Application of Patches

Small amounts of allergens are applied to the skin, typically on the back, using adhesive patches.

The patches remain in place for approximately 48 hours and should be kept dry during this time.

First Reading

After the patches are removed, the skin is examined for initial reactions.

Second Reading

A follow-up evaluation is performed after an additional 24 to 48 hours to assess delayed reactions.

Because allergic responses can take time to develop, multiple readings are essential for accurate interpretation.

To ensure accurate results, patients may be advised to:

• Avoid applying topical medications to the back prior to testing
• Limit sun exposure to the testing area
• Continue most normal activities while keeping the area dry

Specific instructions are provided in advance to optimize testing conditions.

Interpreting Results

Results are carefully reviewed to determine which substances triggered a reaction.

Each positive result is evaluated in the context of the patient’s history and exposures.

Personalized Allergen Avoidance Plan

Patients receive detailed guidance on:

• Products and ingredients to avoid
• Safe alternatives for skincare and personal care
• Strategies to minimize exposure in daily life

This step is critical for achieving long-term improvement.

In addition to identifying triggers, treatment is provided to calm active inflammation.

This may include:

• Topical medications
• Barrier-repair strategies
• Adjustments to skincare routines

Patch testing provides clarity in cases where the cause of a rash is not obvious.

Benefits include:

• Identification of specific allergens
• More targeted and effective treatment
• Reduction in recurrent flares
• Improved quality of life

By addressing the root cause, patients are able to achieve more lasting results.

Once the offending allergens are identified and avoided, symptoms often improve over several weeks.

However, complete resolution depends on consistent avoidance and appropriate treatment. Follow-up may be recommended to ensure progress.

At Treiber Dermatology, patch testing is used as part of a comprehensive approach to diagnosing and managing allergic contact dermatitis.

The focus is on providing patients with clear answers and practical solutions that can be incorporated into daily life.

Patients throughout New York and Connecticut choose Treiber Dermatology for patch testing because of the practice’s expertise in diagnosing complex skin reactions.

Care is known for being:

• Thorough and methodical
• Focused on identifying root causes
• Practical and easy to implement
• Tailored to individual lifestyles

The emphasis is on delivering meaningful, lasting improvement.