In order to be able to diagnose an allergic reaction of the skin and, above all, to determine the triggering substance, the treating physician must first take a medical history. Among other things, he will ask how long the skin rash has existed, whether it has occurred more frequently and whether new skin care products, detergents or drugs have been used. An allergy test can also be carried out.
If contact allergy is suspected, the so-called epicutaneous test or patch test is used in particular. Here, certain test substances are applied to the patient’s back using special plasters and are usually left in place for 48 hours. Then the first reading takes place, i.e. it is checked whether skin irritations have developed in the areas where the various substances were applied.
A new reading is usually taken after a further 24 hours (i.e. a total of 72 hours). In some types of rash, such as urticaria, which is particularly evident in the form of fleeting wheals and severe itching, it is very often not possible to find a triggering cause. In this case, symptomatic therapy is crucial.
Even for a dermatologist it is not always easy to tell whether a rash is an allergic reaction or some other type of rash. For example, especially at the beginning of the warm months, it could simply be a reaction of the skin to increased heat or sunlight. It is therefore not possible to say in general terms what an allergic reaction in the face is.
If a skin rash occurs after a new skin care product has been used on the face for a few days, this can be an indication of an allergic reaction. Pausing the product in question usually gives a relatively quick indication of whether an allergic reaction has occurred. If the rash subsides rapidly after the pause, an allergic reaction is likely to occur.
The nature of the rash alone does not tell us whether it is an allergic reaction or some other type of rash. Facial rash?as described in the previous section, it is not always easy to classify a rash as allergic or non-allergic. This is because an allergic skin reaction has no specific manifestation. Rashes that occur shortly after using a new skin care product should always initially lead to the suspicion of an allergic reaction and should always be followed by a pause in the product. However, numerous other causes such as bacterial or viral infections, skin diseases or other organic causes can also cause rashes that initially make one think of an allergy.
The aim of diagnostics is first of all to find out which allergen has triggered the allergic reaction in the skin area. If this is possible, the first step is to avoid the allergen. This is relatively easy to do with many allergens such as certain cosmetics, nickel, latex or certain detergents.
It should then be switched to another, in the best case hypoallergenic, substitute. Symptomatic treatment can be used to alleviate the acute symptoms of the allergy. For example, by applying locally soothing ointment in the area of the allergic reaction.
These can be used to relieve itching or generally have an anti-inflammatory effect. Antihistamines such as Fenistil® are especially effective against itching. Preparations containing cortisone have an anti-inflammatory effect and also quickly relieve itching.
If it is not possible to find the triggering allergen, only a purely symptomatic therapy can be given. In addition to the above-mentioned local measures with ointments or gels, antihistamines in tablet form are also used. Typical examples are Cetirizine ® or Loratadine ®.
These drugs should usually be taken over several weeks until the symptoms have subsided sufficiently. You can find more information about the treatment of a skin rash here. There are numerous household remedies that can have a soothing effect on allergic reactions in the skin area: Cooling compresses with lukewarm water that are changed regularly can have a calming effect and alleviate itching.
Chamomile is said to have a soothing and antibacterial effect. Cotton wool pads soaked in lukewarm chamomile tea can be placed on the affected areas and left for 20-30 minutes. Apple vinegar diluted with a little water can also help.
A soaked cotton pad can be placed on the affected areas and left for 10-20 minutes. Envelopes with cooling yoghurt or quark can also have a soothing effect on itching and rashes. Aloe vera is also said to have a soothing effect. Various products contain aloe vera and can be applied to the corresponding skin areas.