Standard series patch test

Most chemicals are mixed in petrolatum and are supplied in a syringe. A few chemicals are dissolved in water and are supplied in a bottle. The patches consist of hypoallergenic adhesive paper with up to ten chambers.

The chambers are made of metal or plastic and are round or square. The chemicals have been carefully tested by the manufacturers and by dermatologists to determine the most suitable concentration for testing.

If too weak, some people that are allergic to the chemical will not react to the test substance false negative. If too strong, some people that are not allergic to the chemical will have a positive irritant reaction false positive.

A small amount of a petrolatum-based allergen is carefully squeezed into a chamber. Liquid allergen solutions are dropped onto the filter paper placed in the test chamber. Two or three completed patches are fixed to the skin of the upper back; in some cases, an additional hypoallergenic tape may be necessary to keep them in place. Each patch is carefully numbered or labelled so the allergen in each chamber can be correctly identified.

The patches are generally left in place for 48 hours. The dermatologist will inspect the test site after they have been removed and at least once more, a couple of days later. Preparing the Standard Series of patch test allergens Baseline series of patch test allergens.

The T. The chemicals in the baseline series depend on which one is being used. The European Baseline series used in is described below. Most test substances are single compounds but some of the tests are mixtures of closely-related chemicals. Compared to the European Standard Series, the T. The test panels of 29 allergens include the following chemicals:. Topical antibiotics and preservatives together accounted for 22 cases of contact dermatitis In India many combination preparations such as a steroid with antibiotic, steroid with antifungal and even the combination of all the above three are available.

These preparations are used for prolonged periods. A combination of antibiotic and steroid is used well after the infection has subsided or even on many an occasion when there is no bacterial infection to start with.

This prolonged needless usage is possibly responsible for numerous cases of antibiotic sensitivity. This is the most commonest preservative used and we feel that it should be a part of any standard series. Although parthenium sensitivity is quite rampant in India sesquiterpene lactone has not been included since.

ISS however can be extended with a plant series which is used whenever contact dermatitis to plants or parthenium is suspected. Translate this page into: English. Patch testing with Indian standard series. Indian J Dermatol Venereol Leprol ; Antihistamines can be taken as normal as they do not interfere with the type IV hypersensitivity reaction. There are several thousand potential contact allergens, but some are much more common than others.

A standard series of allergens at least will usually be applied. The composition of the series varies over time and from country to country, as different allergens may become more or less important.

At a pre-patch test consultation, the series of allergens required are selected. This is important so that potential allergens are not missed, and any product dilution arranged. It is helpful to bring health and safety data sheets and product packaging which may list individual allergen ingredients.

If there is a suspicious product that may be the cause of dermatitis, it is important this is brought along to the doctors appointment. Patch testing may be required and its packaging will contain valuable details of its constituents. Some allergens are coloured and will temporarily stain the skin PPD is black, disperse blue is blue, textile resins are a variety of colours.

The colour can be removed with an alcohol swab and these are not to be confused with true positive reactions. Irritant reactions can occur in those with atopic eczema , particularly to metals nickel , chromate and cobalt , perfumes and some rubber accelerators , and are not relevant.

Negative results may mean that the dermatitis is endogenous or irritant in cause, or perhaps the allergen may have been missed not considered or tested for, or may even be a novel allergen. Detailed information sheets can be given for many of the allergens which will guide patients as to where they may find, and therefore avoid, the identified allergen. It is useful to make a note of identified allergens for checking products when shopping. Most countries mandate that allergen constituents appear within or on the packaging or several types of product, particularly personal care items.

Some people will tolerate a product applied to their covered skin, but will react to the product on exposure to light photocontact dermatitis. This can be investigated by photopatch testing; this may be relevant to some fragrances , antiseptics, plant allergens , and sunscreen reactions.

Two identical panels of photopatch allergens are applied to the back, and at 48 hours only one of the panels is exposed to ultraviolet light.