Procedure for Skin Patch Testing | Dermatology

Skin Patch Testing | Patch Testing

What is skin patch testing?

Skin patch testing can be a diagnostic method to determine which specific substances are causing an allergic inflammation of a patient’s skin. A skin patch testing can help determine if a patient has a delayed-type allergic reaction and can detect undiagnosed allergens.


The first date lasts half an hour. Small sizes of 25 to 150 materials are applied to the upper part of the back in individual square plastic or round aluminum chambers. These are secured with special hypoallergenic tape. The patches remain unaltered for 48 hours.

During the second appointment usually, two days later, the patches are removed. Sometimes more fixes are applied. The back is marked with an indelible black tip pen or another appropriate marker to identify test sites. These marks should always appear on the third appointment, usually two days later (4 days after application). The back should be inspected and commented on several times between appointments 2 and 3 if necessary.

During the test week

  • The ink-marked patches and the test area should be allowed to dry throughout the test
  • Do not apply anything to the test area. It contains all soaps, creams, ointments, and moisturizers
  • Do not scratch, massage, loosen, or remove the patches
  • Avoid all physical activity where the band is taking place
  • Do not expose the test area to direct sunlight
  • Avoid hot areas and activities that cause excessive sweating
  • Keep taking the antihistamines that are prescribed for you

The patches must be kept dry. Your child should not bathe. Wash patched areas of the body with a washcloth or bath sponge. Be careful not to get the patches wet.

The first visit for skin patch testing

The patches are usually placed on your child’s back and kept for 2 days.

  • Your child should wear loose, comfortable clothing
  • Your child should wear old dark-colored clothing to prevent the marker from staining

Small plaques, or patches, contain various materials and place them on the skin. Nurses use a marker to erase the edges of the sheets. The sheets are then secured with duct tape or another adhesive bandage (bandage).

The second visit for skin patch testing

The second visit for skin patch testing is usually 2 days after applying the patches. Usually, you take your child to the clinic to remove the patches. The nurses carefully remove the tape and patches. They recall patchy skin. Nurses check the area to see if the skin shows signs of a reaction. In most cases, the reaction may not appear yet. It is still important to return to the clinic to re-examine the area.

Continue to keep the skin dry where the patches are. Do not allow your child to bathe or bathe where there are patches. Do not apply creams, ointments, or moisturizers where there are patches. Do not scratch your child’s skin where there are patches. Your child should stay away from hot areas and activities that cause excessive sweating.

Removing patches: Usually, you should not remove patches yourself. They are usually removed by nurses at a dermatology clinic. Sometimes the doctor would have a family remove a patch at home. If you receive this instruction, you will remove the tape and thoroughly clean the bandage. The edges of the patch test sheets are re-marked with a marker given to you before removing them from the skin.

Sometimes a patch can fall off or be pulled so that it does not touch the skin. The skin patch testing is important that you notify your pediatrician at your next appointment if this happens.

The third visit for skin patch testing

The third visit for skin patch testing is usually 4 to 5 days after applying the patches. Your child will come to the clinic to have his skin checked. It is important to re-examine the skin for skin reactions. Nurses and doctors will look at your baby’s skin and tell you if your child has any ingredients to avoid.

You can reapply topical creams, ointments, and moisturizers after your child’s visit. Your child can bathe and bathe normally.

Results interpretation

The dermatologist or allergist will complete the registration form at the second and third appointments (generally 48 and 72/96 hour readings). The result of each test site is recorded. One system used is the following:

  • Negative (-)
  • Irritant reaction (IR)
  • Equivocal/uncertain ( )
  • Low positive (+)
  • Strongly positive (++)
  • Severe reaction (+++)

Irritant reactions include miliaria (sweat rash), follicular rashes, and burn-like reactions. Undetermined reactions indicate a pink area under the test room. Weak positives are slightly raised pink or red patches, usually with a slight blistering. Strong positives include “papulovesicular” and extreme reactions that cause redness, severe itching, and the spread of blisters or ulcers.

Lev imaging is determined by exposure to positive allergens and is classified as accurate, potential, possible, past, or unknown. If there is a definite picture of an allergen, the patient must undergo the product test and the test must be positive in addition to the allergen.

Probability is used to describe a positive allergen in a product used by a patient (i.e. quaternion-15 listed in moisturizer used at dermatitis sites). Interpreting the results requires considerable experience and training. A positive patch test may not explain the current skin problem, as the test only indicates that the person has become allergic to the chemical at some point in their life.

Therefore, the image of lev should be formed by determining the causal relationship between a positive test and eczema. The diagnosis of v is made after the patient has avoided exposure to the chemical and notices that improvement or elimination of their dermatitis is directly related to this avoidance. This usually occurs within four to six weeks of ending exposure to the chemical.

If all the skin patch testing is negative, the allergic reaction is probably not due to an allergic reaction to contact. However, in rare cases, the patient has not been tested for other chemicals that cause allergic reactions. If suspicion is high despite a negative patch test, further investigation is required.

The skin patch testing is intended to produce a local allergic reaction in a small area of the patient’s back, where diluted chemicals are implanted. The chemicals included in the skin test kit account for about 85-90% of the culprits of allergic contact eczema and metals (for example, nickel), rubber, leather, formaldehyde, lanolin, perfumes, toilets, hair dyes, medicines, celery, foods, foods preservative, and other additives.

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