After a first part of a case study on “health and climate change”, we present below the resolution of the case and explain why it is linked to this topic.
The patient’s initial symptoms, particularly postprandial diarrhea, seem to indicate that involvement begins in the mast cells of the digestive tract. Gradual worsening of symptoms may be due to sensitization caused by repeated exposure to the allergen. It is possible that a certain event has triggered a new allergy. The most common sources in adults are fish, shellfish and nuts.
In contrast, in patients with systemic mastocytosis, the release of mediators by mast cells can be triggered by many causes, such as drugs, stress, exercise, or medical procedures. This patient’s blood count and the absence of hepatomegaly and splenomegaly do not confirm this diagnosis but do not exclude it either.
We confirmed the presence of immunoglobulin E (IgE)-mediated mastocytosis. The reappearance of symptoms on the fourth day suggests reexposure to the same triggering factor. Questioning the patient again, he remembers eating red meat on the fourth day of his hospitalization, which coincides with the worsening, although he had never had problems with meat before. He claims to be a deer hunter and to have eaten deer two days before going to the emergency room.
The picture is very suggestive of an allergy to alpha-galactose or red meat (alpha-gal syndrome). It is a carbohydrate found in all non-primate mammals. Humans can develop IgE antibodies in response to exposure to this substance through consumption of red meat and develop a new allergy. This syndrome is often characterized by the late onset of symptoms (approximately 3 to 8 hours after ingestion), unlike other food allergies which manifest quickly. In a very high percentage of cases, it results in an anaphylactic reaction.
The most common exposure vector in Europe is the tick Ixodes ricinuswhich is most commonly found in wooded areas or areas with abundant shrubs and tall grass. The saliva of this tick may contain alpha-galactose from the animals it has fed on, including deer. This is why alpha-gal syndrome is more common in people living in rural areas, hunters, forest rangers, ranchers, or veterinarians.
Alpha-gal syndrome was originally described in the southern, eastern, and central United States, Australia, and parts of Europe and Asia, but has become more widespread in recent years, with cases reported in France, Italy, and Spain. This expansion is attributed to the effects of climate change, with increasing temperatures and changes in precipitation, habitats, and types of mammalian hosts.
The patient was discharged from the hospital with treatment of decreasing doses of corticosteroids and antihistamines, as well as a recommendation to avoid red meat. Fifteen months later, he went for a check-up and underwent allergy testing. His tryptase and IgE to alpha-galactose levels were normal. He had no new episodes of anaphylaxis.
This case illustrates the extent to which the diseases to which a patient is exposed, and which should be included in their differential diagnosis, are influenced by climate change. In the coming years, especially in Europe, we will have to be attentive to detecting these changes because, in many cases, they will be pathologies that we were not used to considering.
This case study was originally published on Univadis.es.
