Some authors consider MS and its borderline forms to constitute a spectrum, differing only in chronicity, severity, and clinical course, while others consider them discretely different diseases.Typically, ADEM appears in children following an antigenic challenge and remains monophasic. Nevertheless, ADEM does occur in adults, and can also be clinically multiphasic.Problems for differential diagnosis increase due to the lack of agreement for a definition of multiple sclerosis. If MS were defined just by the separation in time and space of the demyelinating lesions as McDonald did, it would not be enough to make a difference, as some cases of ADEM satisfy these conditions. Therefore, some authors propose to establish the separation line in the shape of the lesions around the veins, being therefore "perivenous vs. confluent demyelination". The pathology of ADEM is very similar to that of MS with some differences. The pathological hallmark of ADEM is perivenular inflammation with limited "sleeves of demyelination". Nevertheless, MS-like plaques (confluent demyelination) can appearPlaques in the white matter in MS are sharply delineated, while the glial scar in ADEM is smooth. Axons are better preserved in ADEM lesions.
It is managed in the same manner as anaphylaxis. Anaphylactoid reaction, non-immune anaphylaxis, or pseudoanaphylaxis, is a type of anaphylaxis that does not involve an allergic reaction but is due to direct mast cell degranulation. Non-immune anaphylaxis is the current term, as of 2018, used by the World Allergy Organization with some recommending that the old terminology, "anaphylactoid", no longer be used. Allergy skin testing
Allergy testing may help in determining the trigger. Skin allergy testing is available for certain foods and venoms. Blood testing for specific IgE can be useful to confirm milk, egg, peanut, tree nut and fish allergies.Skin testing is available to confirm penicillin allergies, but is not available for other medications. Non-immune forms of anaphylaxis can only be determined by history or exposure to the allergen in question, and not by skin or blood testing. Differential diagnosis
It can sometimes be difficult to distinguish anaphylaxis from asthma, syncope, and panic attacks. Asthma however typically does not entail itching or gastrointestinal symptoms, syncope presents with pallor rather than a rash, and a panic attack may have flushing but does not have hives. Other conditions that may present similarly include: scrombroidosis and anisakiasis. Post-mortem findings
In a person who died from anaphylaxis, autopsy may show an "empty heart" attributed to reduced venous return from vasodilation and redistribution of intravascular volume from the central to the peripheral compartment. Other signs are laryngeal edema, eosinophilia in lungs, heart and tissues, and evidence of myocardial hypoperfusion.