1. Determine the Cause of the Rash, if Possible
Different allergy rashes require vastly different modes of treatment. For a rash caused by something as simple as poison sumac, for instance, a simple treatment of hydrocortisone, antihistamines, keeping the rash clean and time can resolve 99 percent of situations. However, other allergy rashes may be indicative of more severe conditions, such as fungal, bacterial or viral infections. They may also suggest a growing or potentially dangerous allergy to environmental toxins.
Pediatricians, for instance, have noticed a volatile spike in the number of peanut and shellfish allergies in children over the past decade and a half. If a child comes down with a facial allergy rash after being exposed to almonds or peanuts, simple antihistamine therapy may be enough to solve the symptoms. However, unless the parent seeks deeper knowledge of the potential allergy, the symptoms could reoccur in the future, perhaps under more critical scenarios. If an allergy rash is comorbid with other symptoms, especially shortness of breath, fatigue or nausea, it's probably a good idea to get immediate medical attention.
2. Topical Treatments
Over-the-counter antihistamines, non-steroidal anti-inflammatory drugs, hydrocortisone creams, cocoa butter, aloe butter and other moisturizing and soothing ointments can all help to eliminate or relieve the symptoms of an allergy rash. Be sure to check all labels and search for contraindications, particularly if you're taking other medications or have a history of allergic reactions.
3. Medications to Bring Down the Rash
Prescribed corticosteroids or antihistamines can be useful for treating cases of severe allergy rash or rash that's spread beyond the face to the trunk and the extremities. In the case that you and your physician can't determine whether or not an allergen caused the reaction, you may want to take a course of antibiotics or anti-fungal medications to treat the problem.
4. Time and Rest
Most allergic facial rashes will subside or go away by themselves over time. If the rash itches or creates incredible discomfort, take steps to alleviate the symptoms, but try not to scratch it or spread it around to the rest of the body. Using a cold compress or a hot washcloth to dress the area may take away some of the itching. Simply biding time and allowing the body to heal itself can work wonders.


