There are many health conditions that can cause a rash with vomiting, including allergies, food poisoning, and non-foodborne infections. Certain other illnesses, including Reye’s syndrome and Addison’s disease, can cause these symptoms as well. Many of these illnesses are potentially serious, so a person who experiences both symptoms together should consult a medical professional to determine the cause.
Allergies
One of the most common causes of rash and vomiting is a food allergy. People can develop allergies to a wide variety of foods, including nuts, dairy products, shellfish, eggs, and wheat. Symptoms include lip and mouth swelling, nausea, stomach pains, and diarrhea, in addition to vomiting. The itchy rash that typically develops is also known as hives and tends to appear as large, flat, pink or red bumps.
The symptoms tend to develop quickly, in as little as a few minutes or seconds after eating the trigger food. Most food allergies are not dangerous, particularly in someone who has been diagnosed and knows what to do if a reaction occurs. In people with severe allergies, however, the reaction that occurs can be life-threatening. Dangerous symptoms can include difficulty breathing, feelings of tightness in the throat or chest, dizziness, heart palpitations, and loss of consciousness. These are signs of anaphylaxis, which can cause death if not treated promptly.
Food Poisoning
Many types of food poisoning cause the affected person to vomit, but not all cause a rash. One that does is called histamine toxicity, or scombroid poisoning, which develops after eating improperly stored or prepared fish. In addition to vomiting and a red rash on the chest and back, people with this illness typically have abdominal cramps and a headache. Most of the time, this reaction lasts only a few hours and is not life-threatening; however, the more fish is eaten, the worse the symptoms are likely to be.
Infections
Meningitis is an inflammation of the tissue around the spinal cord and brain; it can be caused by bacteria, viruses, or fungi, but bacterial meningitis is usually more severe than the other types. While this infection can affect people of all ages, it is particularly dangerous to babies and toddlers. Symptoms include fever, vomiting, sensitivity to light, a stiff neck, and headache, accompanied by a pinprick or blister-like rash. The illness can also progress to cause seizures and coma. Anyone who has these symptoms needs emergency medical treatment to prevent severe complications such as blindness, deafness, paralysis, and brain damage.
Toxic shock syndrome is a potentially fatal infection often associated with tampon use in women; however, men and children can also develop this illness. The syndrome is caused by bacterial infection with certain rare strains of Staphylococcus aureus or Streptococcus pyogenes. Symptoms include high fever, a rash, vomiting, diarrhea, muscle aches, and headaches; as the infection progresses, mental confusion and seizures can occur. Those most at risk include women who are or have just finished menstruating, and anyone with a burn, wound, or skin infection.
Scarlet fever typically develops as a complication of a Streptococcus infection that occurs elsewhere on the body, with strep throat being the most common. As well as vomiting and a rash, it causes muscle pain, fatigue, abdominal pain, fever, and headache. The rash is a bright scarlet and appears first on the face, neck, and torso; often, it spreads to the limbs. Medical treatment is required to prevent the development of further complications, which can include meningitis.
Other Health Conditions
The symptoms of Reye’s syndrome are a severe rash on the hands and feet, heavy vomiting, high fever, and lethargy; untreated, it can progress to mental confusion, seizures, and unconsciousness. This illness can be triggered in a child or teenager with a viral infection if he or she is given aspirin, although the condition is also known to develop in other situations with no known cause. Most adults who develop Reye’s syndrome make a full recovery, but in children, it can cause irreversible brain and liver damage.
In Addison’s disease, the adrenal glands cannot produce enough of the hormone cortisol for the body’s needs. The symptoms of the disease are typically mild and can be controlled with medication, and may include abdominal pain, fatigue, muscle weakness, and fever, along with a darkening of the skin. People with Addison’s disease are at risk of an adrenal crisis, a potentially life-threatening situation. Symptoms include severe fever, vomiting, and diarrhea, lethargy, and sudden pain in the abdomen and lower back. The condition may progress to mental confusion and loss of consciousness.
When to Seek Medical Care
Not all conditions that cause a rash with vomiting are serious, but some can be life-threatening. Anyone who experiences symptoms that get worse, or that don’t go away after a couple of days, should visit his or her healthcare provider. If a child has these symptoms, his or her caregiver should schedule an immediate appointment, as many of these illnesses are more dangerous in children. In general, any person with very high fever, severe pain, or neurological symptoms needs emergency medical care.