Whole body allergy: how to respond?

A generalised 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 this, 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 requiring a medical emergency intervention : in such cases, dial 15 for the SAMU in France, 911 in the United States, 999 in the United Kingdom, or 116 117 in Germany.

  While waiting for medical assistance, if this is not the individual's first anaphylactic reaction, it is likely that they carry an injectable dose of adrenaline in the form of a self-injector pen known as an epipen. It is then necessary to urgently administer this dose and, if there is no response, a second dose should be injected within the following five to ten minutes. Adrenaline typically acts within a few minutes to reduce vasodilation, increase blood pressure, and decrease swelling. The patient should then be transported to the hospital, where they will receive further treatment.

• 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 an 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 carry out allergy tests conducted 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 allergen injection site.

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

  If the results of the prick tests are not conclusive, a dosage of specific IgE can be proposed. This test, which requires a blood sample, is generally very effective. Once the allergen is identified, a certain vigilance is required 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 with you.