Mild allergic reactions produce unpleasant but minor symptoms, while severe allergy attacks cause bad and sometimes life-threatening situations. The problems begin when an individual ingests or comes in contact with a substance that offends the immune system. Causes may include individual sensitivities, such as to a food or drug, or general toxic effects from poison ivy or bee stings. Allergy symptoms can arise in the skin and the cardiovascular, digestive and respiratory systems.
Hives
Visibly red, raised, itchy bumps accompany some contact allergies. These hives, or urticaria, may develop after touching poison ivy, poison oak, poison sumac or some metals and chemicals. Hives should fade in 2 to 4 weeks. The Mayo Clinic notes that apparent hive allergy symptoms that persist for more than 6 weeks may have another underlying cause.
Severe Swelling
Swollen eyes indicate reactions to airborne allergens, as in pollen allergies from hay fever, while local swelling characterizes severe insect stings. The Mayo Clinic reports that swelling of the face and throat can occur due to drug or food allergies, which can affect the respiratory system as well.
Difficulty Breathing
Allergic reactions to drugs, foods, insects and even pollen can create trouble for the respiratory system. Hayfever pollens can cause severe congestion with nasal mucus. The Cleveland Clinic reports that food allergy symptoms can arise immediately or as many as four hours after ingestion. Drug and bug sting reactions usually occur right way. Breathing problems involve coughing, wheezing and shortness of breath that mimic asthma symptoms.
Asthma
Individuals who have asthma often suffer periodic allergic sensitivities. These two conditions often interact and can pose serious consequences. For instance, a patient who is suffering from hayfever nasal congestion may face critical breathing problems when asthma compounds respiratory stress.
Chest tightness or pain may accompany recurring cough or other breathing obstructions, as the Cleveland Clinic notes. Isolated symptoms may indicate allergic reactions, while repeat episodes may denote chronic asthma, which should be professionally diagnosed and treated in addition to allergies.
Vomiting
Digestive upset along with respiratory allergy symptoms is usually a sign of a reaction to a certain food. Symptoms include vomiting, diarrhea and abdominal pain or cramps. The University of Maryland Medical Center relates that additional cardiovascular or respiratory symptoms in these cases can be life threatening.
Anaphylaxis
According to the National Institutes of Health, anaphylaxis, the most severe allergic reaction, comes on almost instantly. In addition to digestive and respiratory stress, anaphylaxis can create dangerous heartbeat and blood pressure abnormalities. Overall symptoms can arise from any type of allergy and may include: weakness, light-headedness, mental confusion, weak or rapid pulse and loss of consciousness.
