Skin allergies

Tips for dry and irritated hands (Eczema of the hands)

• Washing hands
Use warm water and a surgras soap then rinse very carefully. While the skin is still damp, apply neutral cream which has been prescribed for you.

• Work in water (dishes, laundry, cleaning)
Use gloves (rubber or polyvinyl with cotton gloves inside them). Do not use them for more than 30 minutes at a time. If water seeps inside, then change them immediately. Always have reserve gloves at your disposal.

• Other work with irritating products also require the same precautions.
Cleaning of floors, glass, furniture, metals, cars, solvents, benzine, turpentine, dyes and hair lotions and kitchen (do not peel or squeeze oranges or lemons with your bare hands -same precautions for tomatoes, potatoes, garlic etc).

• Leather or ‘thick’gloves
Dry work for example in the garden.
-Dirty your gloves, not your hands!
-Wash your gloves as often as necessary.

• Other recommendations
– Wear gloves in the cold weather.
-Do not wear rings while in contact with irritating products such as soap, detergents, etc.

• Duration
The resistance of the skin is decreased for several months after the healing of eczema, therefore it is advisable to follow these instructions for a minimum of 4 months afterwards. There is no quick fix for eczema. Your skin needs time to recuperate.

Information about testing

Application of patch testing

(Finn Chamber, Patch Test IQ) test strips are applied vertically on the back, in parallel rows. With regard to the order of application of the standard battery tests, it is well codified at the present time.

The old implementing of patch testing are no longer in use today. These ancient terms, to ensure better penetration of allergens, include the site to test with sanding paper of glass, abrasion of the layer horny with a scalpel, true scarification forming a grid pattern more or less tight.

The application of the patch test site choice

The choice of the best application of the patch test site is the result of the classical works of Magnusson. It is the high dorsal para-vertebrale region which offers qualities flat surface and grip ensuring good reproducibility of tests.

A few points of detail

Tests are applied to sides of the spine at least 5 cm of part and sides of the midline. They are not placed in the part of the near back of the neck for reasons of discomfort and lower adhesion which would result in a risk of detachment of test equipment and also common irritation of the integument. The region that covers the shoulder blades is favourable. If the tests are more numerous, the lowest areas are also suitable.

These application sites are chosen uniformly around the world. They are not exclusive. If necessary, other sites could be used:
the face inner thigh, the face of the extension of the arm, the face of flexion of the forearm. This choice may be dictated in the event of extreme Hairiness of the back.

On the other hand, it would be interesting sometimes to perform a patch test on a neighbouring territory of the place where the allergic contact eczema is developed. Indeed, it can happen that a test gives a false negative response when it is made too large distance from initial of eczema headquarters, while a nearby test gives a positive response.

An attempt to explain such an unconformity, is used to the concept of memory local or regional memory of the integument. It uses only exceptionally this variation when applied in the dorsal region tests are negative and this negativity seems NET unconformable with the clinic.

In the case of eczema of the eyelids, is used more palpebral test, because of the discomfort it provides to the patient.

Skin condition affecting the application of patch testing

The skin of the back on that patch testing are made must be intact, i.e. devoid of any skin: acne, Folliculitis, psoriasis, Eczema of any nature, of irritation Dermatitis, pityriasis versicolor, pityriasis rosé rosea.

Eczema, in particular, is to reject (status eczematicus) because it would cause false reactions. In the event of excessive Hairiness, a prior shaving will be performed, ideally 24 to 48 hours before the application of the tests (to avoid any residual irritation due to shaving).

Make sure not to proceed with the application of the tests on benign skin tumors, such as prominent moles or seborrhoeic warts for example. A dorsal naevus dermatoscopique may be performed as a screening. The skin shall be no prior preparation for the application of the tests. It should be noted that ether degreasing is no longer topical.

Pregnancy and patch test

There is no scientific reason that justifies the non-realization of patch in pregnancy tests. Nevertheless, as it is a diagnostic method involving the percutaneous penetration of various allergens, a unanimous decision was taken within international groups to suspend the testing until after childbirth or the end of the period of lactation.

This decision, based on the impairment of the integrity of the individual, has especially designed to avoid any dispute, especially in the case of expertise.

Medication systemically and patch testing

The application of patch testing is not compatible with the taking of various types of drugs:

• High-dose corticosteroids
Former work helped clarify that taking corticosteroids at a dose equal to or greater than 20 mg prednisolone/day results in the possibility of false negatives. Than this dosage is compatible with the testing, but the results are to be interpreted with caution.

• Other immunosuppressants
It is not appropriate to patch testing in patients under azathropine, methotrexate, ciclosporin, mycophenolate mofetil, tacrolimus. Under ciclosporin (at a dose of 3 mg/kg/day), can be mitigated positive patch testing, but it is not impossible to think that there is a number of false negatives.

• Antihistamines
In contrast, taking antihistamines, including the latest as cetirizine, fexotenadine hydrochloride, the mizolastine and loratadine is no problem for the implementation of patch testing and should not be interrupted.

Application of drugs by topical and patch testing

It is not appropriate to perform the patch test on the territories that were treated with topical corticosteroids during the week preceding their application.

It is wise to observe a period of withdrawal in topical corticosteroids for one week prior to testing.

He will be with the new topical immunosuppressants such as tacrolimus and ascomycin (SDZ ASM 981) when they will be introduced to the market.

Ultraviolet radiation and patch testing

Any therapeutic by U.V., regardless of its terms, creates a State of anergy which imposes the postponement of the application of the tests (2 months).

It is the same for intense sun exposure.

Testing equipment

Patch testing devices, manufactured by specialized firms, are varied. They are used concurrently in dermatological clinics, without having a mandatory standardisation shall be imposed.

The qualifications for a determined testing equipment are as follows:

• inertia on the allergenic plan
• absence of irritability of the integument by patch testing equipment
• adheres to the seed coat during the 48 hours of application
• surface of reasonable size to avoid any discomfort to the patient and to allow the simultaneous achievement of a high number of patch testing

For a long time, testing materials included the following three (3) components:

  • the pellet which acts as support to the test substance
  • the white washer
  • the adhesive plaste

Allergen: concentration, vehicle, conservation

Each substance is tested at a specific concentration, which was codified by the experience and in an appropriate vehicle.

De Groot (4) brought together information about 3,700 allergens (concentrations and recommended vehicles).

The classical allergens are collected in a series of tests: the series standard, conservative and various special series.

These allergens are prepared by specialized firms.

Application of patch testing

(Finn Chamber, Patch Test IQ) test strips are applied vertically on the back, in parallel rows. With regard to the order of application of the standard battery tests, it is well codified at the present time.

The old implementing of patch testing are no longer in use today. These ancient terms, to ensure better penetration of allergens, include the site to test with sanding paper of glass, abrasion of the layer horny with a scalpel, true scarification forming a grid pattern more or less tight.

Reading patch testing

The calendar

The tests are removed at the 48th time. A first reading is performed 30 minutes after their removal. The second reading takes place, either at the 72nd hour at the 96th time (with a preference for the latter).

Thus, reading patch tests must be carried out in two stages: 48 and 96 hours (ideally), 48 and 72 hours (if the local organization required this time).

Reading at the 48th time cannot be carried out at the time of the removal of materiel (artifacts variety due to the effect of pressure, occlusion and uplift of the material). It is therefore imperative to not read as 20-30 minutes after removal.

In preparation for the second reading, a precise identification of each test site is essential. The tracking is done using a marking pen (e.g..) (Skin marker Chemotechnique) or a fluorescent highlighter (tracking of sites in light of Wood during the second reading). For Finn Chambers, the Boots Hermal firm has created a “boss of reading”, each hole of the corresponding pattern of precise localization of an allergen; Chemotechnique also has his own.

A late reading is always advisable in case complexes (e.g. on the 7th day), because for certain allergens response can become positive that more late (e.g. neomycin, various corticosteroids).

Expression of epucutanes and interpreting test results

The response to the application of an allergen on the seed coat will be three (3) different types: negative, allergic, irritative.

• Subjective symptoms (pruritus, pain, lack of sensation) are random and should not consider only incidentally.

• A negative response is synonymous with lack of any reaction: the seed coat is of normal appearance. There is no detectable lesions.

• A positive response “in miniature” reproduces a clinical picture of eczema, with varying degrees of intensity. Allergic nature responses may extend beyond the territory of application of allergens, with fuzzy limits or, instead, remain perfectly delimited. The allergic reaction is generally spread evenly over the extent of the site, given the regular dispersal of the allergen in vaseline.

• A positive response of irritative nature can take different clinical aspects.

Analysis of the results of the investigation by tests

The sensitivity of a test is its ability to detect an allergic contact eczema. It allows to assess the risk of false negative reactions.

The specificity of a test is its ability to ensure a discrimination between allergic reaction and irritation reaction. It allows to assess the risk of false positive reactions.

The goal in any developed dermato-allergic is the determination of the relevance of the results.

There are:

The current relevance which is to establish a link between the results of positive tests for allergic nature and pathology presented recently by the patient;

Former relevance which is to establish a link between the results of positive tests for allergic nature and a former pathology, without any relationship with developed lesions recently by the patient.

The results of the tests has an interest in this perspective, since they then allow only to draw practical conclusions from the point of view diagnostic, therapeutic and preventive.

The determination of relevance is in some easy cases and other much more complex. All varieties of tests that have been cited in the previous pages may contribute to this determination.

Sometimes the positive patch testing allergic in nature sufficient to support the relevance. In other cases, on the contrary, they must be confirmed by further tests (iterative open tests, tests of use etc.).

Different forms of testing

• Open test (“open test”) is to apply the allergen skin territory (e.g. 5 x 5 cm) without occlusion. The locations of choice are the flexion of the forearm, the crook of the elbow face or the face of the arm extension.

The use of this test is interesting in case of suspicion of a contact urticarial reaction (reading in the 20th minute, for example the Peru Balsam ave) or even when it skips the irritating power to the product testing. This technique of unoccluded prevents possible necrosis of the site tested, if the tested product is caustic.

• The “semi-open” test is a useful variant, when testing products whose chemical composition is not known.

The method is to apply a product open on a limited area of the integument: if it is a liquid (aqueous solution, oil, etc.) the application of two or three drops on a zone of + or – 1 cm2 is recommended. After a few minutes, the tested area is covered by a strip of adhesive tape Micropore ™, which provides the semi-occlusion and the identification of the tested website.

This method is very useful in investigations of industrial Dermatology.

• Iterative open tests (‘Roat Tests’)
A very useful test, to determine the appropriateness of a positive patch test to a specific allergen, is of iterative applications of the same allergen, open, concentration and in a nearby vehicle of its use in everyday life.

This is the open test or ROAT test (Repeated Open Application Test) Hannuksela. In practice, applying the allergen twice per day on a surface clear of the integument (e.g. 5 x 5 cm) or on the face of flexion of the forearm, either on the face of the extension of the arm, or in the scapular region. We stop the applications in case of positivity of the test.

If at the end of 14 successive applications, the test is negative, it puts an end to the test and is considered the test as negative. The cooperation of the patient is paramount.

• In-use tests (“Use Test” or “In Use Test”)
The use test is to apply a finished offending the cutaneous territory where he is supposed to have previously caused eczema. This application is done in conditions quite similar to those for use in everyday life.

For example, if there is suspicion of allergenicity of used cleaning to bare hands, we recommend that you ask about the presumed allergic reuse according to the terms and conditions of employment which are usual.

A suspected allergic to a rubber glove reaction can be checked in fine by the port reiterated this glove, which must lead to the reappearance of eczema. The active cooperation of the patient is essential.