Whole body allergy: how to respond?

A generalized allergic reaction is not harmless and can vary in intensity, ranging from a benign giant urticarial rash to a potentially fatal reaction: anaphylaxis. To avoid it, it is essential to respond quickly and adopt certain measures, the first step being to assess the extent of the reaction.

• If the allergic reaction is severe.

  If the allergy is accompanied by severe symptoms, such as breathing difficulties, swelling of the face or throat, nausea, vomiting, a drop in blood pressure, or dizziness, this could indicate an anaphylactic shock, a reaction that requires a medical emergency intervention : in such cases, dial 15 for SAMU in France, 911 in the United States, 999 in the United Kingdom, or 116 117 in Germany.

  While waiting for help, if this is not the person's first anaphylactic reaction, it is likely that they carry a dose of injectable adrenaline in the form of a self-injector pen called an epipen. This dose should be urgently administered, and if there is no response, a second dose should be given within the next five to ten minutes. Adrenaline typically works within a few minutes to decrease vasodilation, increase blood pressure, and reduce swelling. The patient should then be transported to the hospital, where they will receive further care.

• If the allergic reaction is moderate.

  Even if the allergic reaction does not appear to pose a risk of anaphylaxis, it is recommended to ensure this by promptly consulting a doctor. If the allergy is indeed harmless, the doctor can prescribe a antihistamine to alleviate symptoms and soothe itching. These medications work by blocking histamine receptors, thus limiting the extent of the inflammatory response. If the allergic reaction persists despite taking antihistamines, the doctor may recommend using cortisone creams, which also help to reduce inflammation by inhibiting the production of pro-inflammatory cytokines. However, their use should be occasional as they can lead to thinning and weakening of the skin.

  Tip : Alongside the treatments prescribed by the doctor, it may be beneficial to regularly apply cold compresses to the areas of itchiness. Indeed, due to its vasoconstrictive properties, the cold can reduce blood flow and thus limit the circulation of inflammatory mediators responsible for itching.

• Regardless of the severity of the allergic reaction.

  Finally, even when it is not accompanied by respiratory symptoms, a full-body allergy is not harmless. Thus, after managing the emergency, it is crucial to identify the responsible allergen, so that the reaction does not recur. For this, it may be beneficial to conduct allergy tests performed by an allergist, such as the prick test. This involves placing a drop of several allergens on the skin, before lightly pricking it to allow the substances to penetrate the epidermis. In case of an allergy, swelling, redness, or itching appear within a few minutes at the injection point of the allergen.

  Prick tests can sometimes cause extensive skin reactions, hence the importance of having them performed by a healthcare professional and not attempting to do them yourself.

  If the results of the prick tests are not conclusive, a dosage of specific IgE can be proposed. This test, which requires a blood draw, is generally very effective. Once the allergen is identified, a certain vigilance is necessary to avoid it in the future, whether it's a particular food or everyday allergens, such as dust mites. Furthermore, if the allergist believes you are at high risk of a severe allergic reaction, they may train you in the use of an adrenaline auto-injector pen and advise you to always keep one on hand.