Morphine is an opioid drug to which some people may have an allergic sensitivity. Some of the signs of an allergic reaction to morphine may include a skin rash and itching. Gastrointestinal problems, such as vomiting, may also occur. A severe allergic reaction to morphine will often cause swelling and breathing difficulties, and it could possibly be fatal.

Opioid drugs are derived from the opium plant. Many of these drugs are strong pain killers typically used to help manage severe pain. An allergic reaction to morphine can occur when a person's immune system reacts negatively to the drug. During this, the immune system will often release a substance known as histamine, which can cause a number of allergy symptoms.

A rash is one of the most common signs of an allergic reaction to morphine. The rash may be confined to a small section of the body, but it could also spread to the rest of the body. Hives may also occur, and a person who is allergic to morphine may develop a sensitivity to sunlight.

Pruritus, or itching, is another possible sign of an allergic reaction to morphine. Although itching can be one of the possible side effects of morphine, severe itching can indicate a morphine allergy. This typically occurs on and around the face, but the rest of the body may feel itchy as well.

Nausea is another common side effect of morphine. Severe gastrointestinal problems, however, are sometimes caused by an allergic reaction to morphine. An allergy may not only cause nausea, but it can also cause vomiting and diarrhea.

Swelling can also occur when a person with an allergy takes morphine. Typically, the face and surrounding areas will swell. The lips, tongue, and throat may even swell. If the throat swells, a person's airways may constrict, which will usually cause breathing difficulties. Some severe morphine allergies may even prove fatal, if a person is unable to breathe because of this.

Individuals with certain medical problems, including drug allergies, are often urged to wear a piece of medical alert jewelry. This is often a necklace or a bracelet. A little metal tag on the piece of jewelry includes some information about a person's medical problems. For instance, a person with a morphine allergy may wear a medical alert bracelet stating so. In the event that the person is in an accident and unable to speak, this bracelet lets the doctors know that he can't be given morphine.