With allergies, a rash on the skin appears very often. About how such a phenomenon looks, and how to treat it, we will tell in the materials of this article.
Basic information
The term "allergy" refers to the hypersensitive state of the human immune system during repeated exposure of the allergen to the body, previously sensitized by it.
For allergies, a rash may appear immediately or after a few days. It is necessary to treat this condition. How to do this, we will tell below.
Development reasons
Why does a rash appear with allergies in children and adults? As mentioned above, the reaction in question is the personal intolerance of one or another factor. Such an unpleasant symptom as a rash is a consequence of a specific reaction of human immunity.
Allergic skin rashes may occur due to the following factors:
- certain drugs;
- foods such as nuts, honey, citrus fruits, dairy products, chocolate (most often an allergic rash due to food appears on the face);
- some types of fabrics (for example, synthetics or wool);
- chemicals, including household chemicals;
- cosmetics;
- animal hair;
- plant pollen;
- some types of metals;
- insect bites (a similar reaction is called insect).
It should also be noted that an allergic rash, the photo of which is presented in this article, may occur even due to exposure to cold.
Appearance
What does a rash look like with an allergy? Such manifestations on the skin are distinguished by the following features:
- spot color can vary from pink to bright red;
- rashes on the covers usually do not have a clear shape (they are spots with blurry and fuzzy edges);
- peeling may occur at the site of the rash;
- most often, a rash of allergic origin is similar to a nettle burn, although such rashes can also take the form of nodules, spots, weeping vesicles and blisters;
- in the place of the rash, the skin is usually very irritated, sometimes swelling is observed on it;
- food allergies usually occur on the face, in particular on the cheeks and in the area around the mouth (it can also occur on the stomach, arms, back, legs).
Where does it appear?
With allergies, the rash can be localized in various parts of the body. For example, irritation with contact dermatitis appears in the place where the skin came into contact with the allergen. The reaction to household chemicals usually occurs on the hands, and on wool or synthetics, for example, when wearing trousers made of this material, only on the lower extremities. With other types of allergies, irritation can be observed anywhere. 
Few people know, but with allergies, a rash does not always occur. There may not be spots or dots on the body. In some cases, such a reaction is manifested only by redness and swelling. Typically, this phenomenon is observed with hay fever, that is, with allergies to pollen.
Concomitant allergic symptoms
An allergic rash is just one of several signs of intolerance to a particular allergen. In addition to skin irritation, such a pathological condition can be accompanied by other unpleasant phenomena. Usually they include:
- choking cough;
- tearing;
- severe itching of the skin;
- redness of the visual organs;
- sneezing
- annoying runny nose;
- photophobia.
As for an increase in body temperature, with allergies, such a symptom develops extremely rarely. Most often, this symptom does not arise due to the fact of an allergy, but as a result of infection. For example, if a child has multiple bites on his hands, and he began to comb them intensively, then in the end he will become infected. 
If skin irritation really has an allergic etymology, then usually a person feels quite normal. However, he does not have any ailments. An allergy rash in children can be troubling, but this is only the result of severe itching of the skin.
Other symptoms
How does an allergy to antibiotics manifest? A rash on the skin (treatment of this condition should be carried out necessarily) when taking this or that medication is a drug urticaria. This reaction to the drug is called a side effect. Usually, its possible appearance is warned in the instructions, which are attached to many medicines and even to multivitamin complexes. If the patient is allergic to pollen, and this allergen has got into his gastrointestinal tract, then he may begin vomiting, nausea, and severe abdominal pain.
When should I sound the alarm?
If an allergic rash (a photo of such irritation can be found in this article) has arisen on the child’s body, then he should definitely measure his temperature. In this case, you need to pay special attention to whether your baby has any breathing problems. If it is difficult, then you should immediately consult a doctor, as this may indicate the development of such a serious complication as Quincke's edema.
Reasons to see a doctor
Types of rashes with allergies can be different. Such irritation can be localized in one place or cover the whole body. In any case, when you see a rash of unknown origin on the skin, you should definitely contact a specialist. What is the reason for such urgency? 
- In the absence of the necessary treatment, a rash with allergies can develop into a serious complication, for example, bronchial asthma.
- It is quite problematic to identify independently what exactly served the development of such irritation. In most cases, this requires laboratory tests. In order to determine the type of allergen, the doctor must make skin tests or refer the patient for a blood test.
- Not always skin irritation indicates the development of an allergic rash. This phenomenon may also be a symptom of an infectious disease (for example, rubella, chickenpox, herpes zoster, and others). All these diseases are contagious and require constant monitoring by a specialist.
- A rash on the skin can also be a common dermatological disease (including lichen, psoriasis, or eczema). It is extremely important to diagnose the disease at the initial stage of its development. Only in this case, the treatment will be most effective.
- A rash that appears on the skin may be the result of an insect bite. For example, after a bite by an ixodid tick, irritation may not appear for a rather long time (from 2 weeks to 1 month). It is very difficult to identify on your own that the tick bite was the cause of the spots. In this regard, you can skip the development of such a dangerous disease as borreliosis.
Even if the patient is completely sure that the rash on his skin is of an allergic nature, only an experienced doctor should carry out its treatment. As a rule, special ointments are used to treat this condition. If the case is neglected and severe, then the patient may need a whole range of drugs.
How to get rid of a rash?
How long does an allergy rash go through? Independently, such irritation disappears only after contact with the allergen has been completely stopped. This usually takes several days or even weeks. If the patient does not know why such rashes appeared on his skin, then he should consult a doctor. After the examination, the doctor will be able to draw up a hypoallergenic diet or teach the patient principles that will minimize contact with the established allergen.
Allergic rashes can also be treated with immunotherapy. For this, the patient is given injections with a microdose of the allergen (sublingual drops can be used). To completely eliminate an allergic rash, a rather long course of treatment may be required, as a result of which the so-called “antidote” to the allergen is developed in the human body.
How is antibiotic allergy treated? A skin rash, the treatment of which should only be carried out by an allergist, very often occurs after taking certain drugs. Paradoxically, various medications are also used to eliminate it. As a rule, they are intended for topical application (for example, Triderm, Pimafukort and others). Although the doctor may prescribe them in combination with medications for oral administration (for example, with Clemastine, Tavegil, Suprastin, Loratadin and others).
How to treat allergies in children?
Allergic rashes in children can occur for various reasons. When observing such irritation, you should remember what kind of food your child consumed in the last few hours. Very often, the cause of the development of an allergy in a baby is washing powder, previously not used in the family. Another reason for this phenomenon may be taking certain medications or replacing baby cereal.
A child prone to allergic reactions should, if possible, refrain from contact with cosmetics, creams or soap. If irritation has already occurred, then antihistamines are used to treat the baby. To prevent the subsequent appearance of a rash, it is necessary to protect children from an established source of allergen. To determine it, you need to contact an allergist.
With such a pathology, it is very important not to let the allergy "on its own." If no action is taken, then such a reaction may become more complex and develop into asthmatic dermatitis, hay fever, or bronchial asthma.
Prevention
What measures to take to prevent an allergic rash from developing? To do this, you must adhere to the following rules:
- Pregnant women should take antibiotic drugs with extreme caution, and also follow a certain diet.
- Nursing mothers should not abuse foods that cause allergies (e.g. chocolate, chicken eggs, fish, citrus fruits).
- Children born to allergy sufferers need longer breastfeeding.
- Babies suffering from food allergies should avoid eating salty and spicy foods, canned and pickled foods.
- Allergy sufferers need to refrain from contact with animals and dust in the house.