The symptoms of a drug allergy usually appear within one hour of taking the medication. But the reaction sometimes occurs later – after several hours, days or even weeks. The symptoms that start soon after taking medication may include the following: Red and unusually warm skin.
Drug rashes are a side effect of a drug that manifests as a skin reaction. Drug rashes usually are caused by an allergic reaction to a drug, but some drug rashes are not allergic. Typical symptoms include redness, bumps, blisters, hives, itching, and sometimes peeling, or pain.
The most common type of drug reaction is hives, also known as urticaria. They are raised, swollen, red or flesh-colored bumps or welts that appear on the skin. They can take on many shapes and can be very itchy. They usually develop in groups and may cover large areas of skin.
Symptoms of a serious drug allergy often occur within an hour after taking a drug. Other reactions, particularly rashes, can occur hours, days or weeks later. Drug allergy symptoms may include: Skin rash.
The most common antibiotic that elicits an allergic reaction is penicillin (think penicillin G)—with 8% of Americans reporting this allergy—followed by sulfonamides and tetracyclines.
Anaphylaxis symptoms usually occur within minutes of exposure to an allergen. Sometimes, however, anaphylaxis can occur a half-hour or longer after exposure. In rare cases, anaphylaxis may be delayed for hours.
Type IV reactions are also called 'delayed hypersensitivity reactions'. These reactions can happen from 12 to 72 hours after exposure to the allergen. For example, contact dermatitis, some lung conditions, type I diabetes and organ transplant rejection.
Side effects can happen within minutes after ingesting a medicine. It can also take hours or days depending on how long it takes for it to metabolize in your body.
An adverse reaction is an unexpected negative reaction to a medication or treatment that happens even when used correctly. Any prescription drug, over-the-counter (OTC) medication, nutritional supplement, and botanical health product can potentially cause adverse reactions.
Antihistamines block histamine, alleviating discomfort related to a drug reaction. The medication is taken by mouth, typically for a few weeks. An over-the-counter antihistamine may be effective, or your doctor may give you a prescription.
Skin rashes, itching or hives. Swelling of the lips, tongue or throat. Shortness of breath, trouble breathing or wheezing (whistling sound during breathing) Dizziness and/or fainting.
The early symptoms may be mild, such as a runny nose, a skin rash or a “strange feeling.” These symptoms can quickly lead to more serious problems, including: Trouble breathing. Hives or swelling. Tightness of the throat.
The first signs of an anaphylactic reaction may look like typical allergy symptoms: a runny nose or a skin rash. But within about 30 minutes, more serious signs appear. There is usually more than one of these: Coughing; wheezing; and pain, itching, or tightness in your chest.
Untreated allergies can get worse, with more severe allergy attacks occurring over time. These frequent or prolonged allergic reactions can also weaken your immune system and set you up for dangerous complications, such as bacterial or fungal infections in the sinuses, lungs, ears or skin.
If your skin starts to blister up or you see pustules, or if you notice sores in your mouth, eyes, or your genitalia, these are red flags and you should get to an urgent care clinic or the ER and ask for a dermatology consultation.