An "acute allergic reaction" can sometime occur when a pet is exposed to some substance which cannot be tolerated by its body. Acute allergic reactions usually occur soon after the exposure to the specific offending substance. Common Causes: Bee stings, wasp stings, spider bites, vaccinations, antibiotic injections, and sometimes certain plants. Signs Include: Watery eyes, swollen eye lids, rubbing the face, swollen ear flaps, and "welts" or "wheals" (small accumulations of fluid in the skin). These signs, although uncomfortable, are usually not life-threatening. The major concern occurs within the body. It is very common for the lungs to fill with fluid, making it harder for the animal to breathe properly. This can be life-threatening, and your veterinarian should be contacted immediately. Allergic dermatitis may be caused by dust, weeds, molds, grass, food, fleas, and many other materials. In dogs and cats, the most common symptom is itching. This causes the pet to chew and scratch, which in turn causes more damage to the skin. The skin often becomes infected or thickened from prolonged chewing and scratching. Allergies are often not preventable, but control with medications is effective if the owner gets proper medical attention as soon as symptoms are seen, and is diligent with treatment.