Patch Testing

Diagnosing unknown rashes, outbreaks, and allergic reactions.

patch testing seattle

When there is a suspicion that an allergy to something which is coming into contact with the skin is causing a rash, our recommendation is to do a form of allergy testing called patch testing.

Patch Testing results will change your quality of life. Patch testing is a common diagnostic tool used to identify the specific agent that triggers contact dermatitis. Contact dermatitis is an itchy rash that can breakout on your skin in response to a substance to which you are allergic. Common trigger substances include poison ivy, jewelry, hair care products, cleansing solution, detergent, cosmetics, perfumes, and latex rubber. What's important to realize about this is that, in most cases you have to be exposed to a particular chemical for an extended period of time before the allergy develops. You are not born allergic to these things.

Making an appointment for patch testing

If you have an unknown skin condition, a recurring skin issue, and a seemingly random outbreak of any rash or blisters, than it's suggested to request an appointment for patch testing with one of our dermatologists for an individualized assessment of your specific skin type and its own allergic reactions. Patch testing routinely delivers shocking results to patients who partake in this diagnosis.

Our Patch Testing Process:.

Abnormal skin growths of any kind can be extremely uncomfortable as well as a risk to your health. It's important to avoid self-care of any growth on your skin to avoid neglecting what is most likely a deeper issue. Our preferred mode of treatment for these little invaders is cryosurgery which is quick, pain free, and effective if carried out by a dermatologist.

First Appointment:

The first appointment will take about half an hour. Tiny quantities of 25 to 150 materials in individual square plastic or round aluminium chambers are applied to the upper back. They are kept in place with special hypoallergenic adhesive tape. The patches stay in place undisturbed for 48 hours.

Second Appointment:

At the second appointment, usually two days later, the patches will be removed.Sometimes further patches are applied. The back is marked with an indelible black felt tip pen or other suitable marker to identify the test sites.

Third Appointment:

These marks must still be visible at the third appointment, usually two days later (4 days after application). The back should be checked and if necessary remarked on several occasions between the 2nd and 3rd appointments.

Patch Testing Results:

The dermatologist will complete a record form at the second and third appointments (usually 48 and 96 hour readings). The result for each test site is recorded.
The system we use is as follows:

•    Negative (-)
•    Irritant reaction (IR)
•    Equivocal / uncertain (+/-)
•    Weak positive (+)
•    Strong positive (++)
•    Extreme reaction (+++)

Irritant reactions include sweat rash, follicular pustules and burn-like reactions. Uncertain reactions refer to a pink area under the test chamber. Weak positives are slightly elevated pink or red plaques. Strong positives are ‘papulovesicles’ and extreme reactions are blisters or ulcers. The relevance depends on the site and type of dermatitis and the specific allergen. The interpretation of the results requires considerable experience and training. [ Request your patch testing appointment today }

Result Examples from Patch Testing

patch testing downtown seattleNegative - Standard Reactions (-)
patch testing dermatologyPositive - Weak Positives (+)
patch testing skinPositive - Extreme Reactions (+++)