Contact Allergy Testing (Patch Testing) Information for parents and carers of children up to 12 years of age

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1 Contact Allergy Testing (Patch Testing) Information for parents and carers of children up to 12 years of age Dermatology Department The aim of this leaflet is to give you information about contact allergy (patch testing) for your child. Please read the information carefully before you bring your child for appointments. Why does my child need to have patch tests? Your child has been referred to the patch test clinic so we can find out whether their condition is caused or made worse by an allergy to substances which comes into contact with his/her skin. Such substances may be found at home, school or nursery. Common examples depend on the age of the child but may include perfumes, bath products, and even the creams or ointments used to treat skin conditions. What does patch testing involve? Three visits to hospital are usually required (Monday, Wednesday and Friday). Allow up to two hours for your child s first clinic appointment and up to one hour for the second and third appointments, although for most patients appointments will be shorter than this. Occasionally a fourth visit may be required. Your child s doctor or senior nurse will inform you if this is needed. Your child s doctor or senior nurse may decide not to patch test your child if he/she: Is unable to attend all three appointments. Has had his/her back exposed to sunlight, for example, during a foreign holiday in the six weeks prior to testing. Has a skin rash which is too active on the patch test site. Is on a high dose of steroid pills or immunosuppressants. Has used strong steroid creams/ointments on the test site less than 48hours before. If in doubt or any of these apply, please telephone the clinic to rearrange your child s appointment. Is any preparation needed? Do not apply topical steroid on your child s back for 48 hours before the test. Do not use moisturisers on your child s back on the day of the test. Avoid sunbathing at least 6 weeks before the test. Page 1 of 5

2 What will be tested? Your child will be tested to a standard series common allergens/chemicals, and perhaps further allergens depending on your child s condition. Your child may also be tested with some of the products that he or she uses at home. In addition, as patch testing is an evolving investigation with new allergens being discovered each year, we may test your child to trial substances as part of the ongoing process of assessing new environmental allergens. Is there anything I should bring for my child to the Patch Test Clinic? Please think carefully about things that your child comes into contact with that might be important for us to test your child for. On the first appointment visit, please bring the following including the leaflet and packaging (if possible): Creams, lotions or ointments your child has been prescribed. Relevant personal care products, cosmetics, perfumes or any other products that you suspect have caused or worsen your child s condition. If your child s face is affected, think about possible airborne factors such as sprays and aerosols. It may not be possible to test every single product that has been brought in. The doctor or senior nurse will decide which if any of the products are suitable and relevant for testing. What happens during the first visit - Monday? The doctor or senior nurse will assess your child and decide which tests are needed. The staff member who applies the patch tests will explain the procedure on the day. Briefly, this involves placing a number of small discs /chambers that contain the test substances under a sticky hypoallergenic tape on to your child s skin (usually the back, occasionally the upper arms). The sticky tape remains in place until your child s next visit on Wednesday. Patch tests in place After the patches are applied to your child s skin, a map will be made of their positions using clear polythene film, which we will keep; we will also outline the patches on your child s back using a skin marker pen. The combination of these marks and the polythene map will allow us to identify any positive reactions. Therefore, it is very important that these marks are not washed off before the readings. You can wash your child if necessary but please do not get the test sites wet. The skin marker pen has ink that may stain your child s clothing. It is therefore advisable to dress your child in an old top. It is helpful to check from time to time that the patches are securely attached to the skin, especially in the morning when your child first gets out of bed. If the patches are becoming loose, simply apply a further piece of hypoallergenic tape (for example, micropore) to secure them in place. Page 2 of 5

3 What happens during the second visit - Wednesday? On your child s second visit, the tapes will be removed and any reactions noted. Additional patches may be applied at this time. Staff may re-draw the outlines of any faded pen marks. Occasionally the skin on your child s back may get irritated by the tapes and so your child might be asked to wait until the redness settles down slightly. The pen marks and/or additional patches will need to remain on your child s back until the next visit on Friday. What happens during the third visit - Friday? On your child s third visit, final readings will be taken and advice will be given at that time on any allergies discovered and further management of your child s condition. For most patients, this will be the final visit but occasionally, a fourth visit is required. If so, the pen marks will need to remain on your back until then. What happens on the patch test site? Positive reactions are red and itchy and apparent by the Friday reading. This usually disappears after a few days. The doctor or senior nurse will often apply a topical steroid on these sites to settle it down more quickly and you may need to continue application on your child for a few more days afterwards. Occasionally reactions are delayed; if your child develops a late reaction, please contact the clinic to arrange a further appointment for reading. The telephone number is on the back of this leaflet. If the degree of itch becomes unbearable (this is unusual, but occasionally occurs) before the patches are due to be removed, you may peel back (carefully) the tape from the area that is itching. If the area is red and raised or blistered, the small metal disc at that point may be removed carefully with a pair of scissors please make a note of the number written on the tape, and the date/time of removal. Try to prevent your child from scratching (however difficult this is), as this will make interpretation of the test difficult. It may be possible for your child to take antihistamines to help with the itch though please call and check with the clinic first. Some of the allergens can stain the skin and this is normal. Negative patch tests are still helpful since, as far as we can, we have eliminated contact allergy as a cause of your child s skin problem. What side effects may occur? Positive reactions will make your child s skin red and itchy at the test site; A strong reaction may cause a blister. Some reactions may persist for up to a month. Positive reactions may be accompanied by a flare of existing or previous eczema. An increase or decrease in pigmentation may occasionally occur at the site of patch tests which may last for months or rarely (1 in 1,000) be permanent. Infection may rarely occur and will require antibiotics. Page 3 of 5

4 Scarring is very rare (1 in 10,000). Rarely (about 1 in 5000 patch tests), your child may become allergic to one of the substances applied during patch testing. In practice, this does not seem to cause a problem in the long term. Don t: Do: Get your child s back or other tests sites wet or bathe, swim or shower during the week of tests. A cool shallow bath or wash down with a flannel is a good alternative. Dress your child in cherished or pale-coloured clothing as the tests and the marker ink may permanently stain it. Expose your child s back to the sun or artificial sunlight (sun lamps) during the week. Apply any emollient or topical steroids on your child s back/other test sites during the week. Scrub the marking ink or apply any chemical/spirit to remove it after the test week. It will wash off eventually with normal bath/shower. Dress your child in an old shirt or top during the week of the tests. Dress your child in a shirt or vest to sleep in to protect the patches. Do be careful when dressing / undressing your child. Clothes that open at the front can be easier to take on and off than those which go over your child s head. Make sure that your child avoids exercise or too much physical activity for that week. It may also be best for your child not do any sports, PE or gym class for that week, so that the patches remain in place. Tape the edges of any loose patches using Micropore tape. If the whole patch comes loose, remove it and note the time and date. Contact the clinic if you are concerned about your child. Will my child require any other additional tests? Some patients may require additional tests during the week, for example skin prick testing. If so, your child s doctor will advise you accordingly and provide you with a separate information sheet. What happens to my child s results? We will record the information about your child s patch test results in his/her medical notes and inform your child s GP. The results will also be stored in an anonymised form on a computerised database, and will be used for audit in accordance with good medical practice. The data may also be used for research and shared with other centres. Contact details The medical and nursing staff will be pleased to answer any questions that you may have about patch testing during your child s hospital visits. Page 4 of 5

5 Department of Dermatology Outpatient Clinic: Ninewells Hospital Telephone: Developed by Consultant Dermatologists at Ninewells Hospital and reviewed by medical and nursing staff, with help from patients and the British Contact Dermatitis Society. Revised: 10/2017 Review: 10/2019 LN0491 Page 5 of 5