The theory of autoimmune attack claims that a person with neuroimmunologic disorders have genetic predisposition to auto-immune disorder, and the environmental factors would trigger the disease. The specific genetics in myelitis is not completely understood. It is believed that the immune system response could be to viral, bacterial, fungal, or parasitic infection; however, it is not known why the immune system attacks itself. Especially, for immune system to cause inflammatory response anywhere in the central nervous system, the cells from immune system must pass through the blood brain barrier. In the case of myelitis, not only is the immune system dysfunctional, but the dysfunction also crosses this protective blood brain barrier to affect the spinal cord.

Myelitis occurs due to various reasons such as infections. Direct infection by viruses, bacteria, mold, or parasites such as human immunodeficiency virus (HIV), human T-lymphotropic virus types I and II (HTLV-I/II), syphilis, lyme disease, and tuberculosis can cause myelitis but it can also be caused due to non-infectious or inflammatory pathway. Myelitis often follows after the infections or after vaccination. These phenomena can be explained by a theory of autoimmune attack which states that the autoimmune bodies attack its spinal cord in response to immune reaction.

Normally, some measure of improvement appears in a few weeks, but residual signs and disability may persist, sometimes severely.

The disease can be monophasic, i.e. a single episode with permanent remission. However, at least 85% of patients have a relapsing form of the disease with repeated attacks of transverse myelitis and/or optic neuritis. In patients with the monophasic form, the transverse myelitis and optic neuritis occur simultaneously or within days of each other. On the other hand, patients with the relapsing form are more likely to have weeks or months between the initial attacks, and to have better motor recovery after the initial transverse myelitis event. Relapses usually occur early, with about 55% of patients having a relapse in the first year and 90% in the first five years.

It is possible that the relapsing form is related to the antiAQP4+ seropositive status and the monophasic form related to its absence Unlike multiple sclerosis, Devic's disease rarely has a secondary progressive phase in which patients have increasing neurologic decline between attacks without remission. Instead, disabilities arise from the acute attacks.

Approximately 20% of patients with monophasic Devic's disease have permanent visual loss, and 30% have permanent paralysis in one or both legs. Among patients with relapsing Devic's disease, 50% have paralysis or blindness within five years. In some patients (33% in one study), transverse myelitis in the cervical spinal cord resulted in respiratory failure and subsequent death. However, the spectrum of Devic's disease has widened due to improved diagnostic criteria, and the options for treatment have improved; as a result, researchers believe these estimates will be lowered.

The prevalence and incidence of Devic's disease has not been established, partly because the disease is underrecognized and often confused with MS. Devic's disease is more common in women than men, with women comprising over two-thirds of patients and more than 80% of those with the relapsing form of the disease.

A retrospective study found that prevalence of NMOsd was 1.5% inside a random sample of neurological patients, with a MS:NMOsd ratio of 42.7. Among 13 NMOsd patients, 77% had long spinal cord lesions, 38% had severe optic neuritis and 23% had brain or brainstem lesions. Only 56% had clinically definite NMO at follow-up.

According to the Walton Centre in England, "NMO seems to be present across the world unlike MS, which has a higher incidence in temperate climates and white races. Africans and Asians especially in Far East may have a higher risk of NMO, although the exact incidence of this disease is unknown, making specific conclusions difficult". Although many people who have Devic's disease were initially misdiagnosed with MS, 35% of African Americans are often misdiagnosed with MS when they really have NMO.

Devic's disease is more common in Asians than Caucasians. In fact, Asian optic-spinal MS (which constitutes 30% of the cases of MS in Japan) has been suggested to be identical to Devic's disease (differences between optic-spinal and classic MS in Japanese patients). In the indigenous populations of tropical and subtropical regions, MS is rare, but when it appears, it often takes the form of optic-spinal MS.

The majority of Devic's disease patients have no affected relatives, and it is generally regarded as a nonfamilial condition.

CNS demyelinating autoimmune diseases are autoimmune diseases which primarily affect the central nervous system.

Examples include:

- Diffuse cerebral sclerosis of Schilder

- Acute disseminated encephalomyelitis

- Acute hemorrhagic leukoencephalitis

- Multiple sclerosis (though the cause is unknown, it is sure that immune system is involved)

- Transverse myelitis

- Neuromyelitis optica

The role of prolonged cortical myelination in human evolution has been implicated as a contributing factor in some cases of demyelinating disease. Unlike other primates, humans exhibit a unique pattern of postpubertal myelination, which may contribute to the development of psychiatric disorders and neurodegenerative diseases that present in early adulthood and beyond. The extended period of cortical myelination in humans may allow greater opportunity for disruption in myelination, resulting in the onset of demyelinating disease. Furthermore, it has been noted that humans have significantly greater prefrontal white matter volume than other primate species, which implies greater myelin density. Increased myelin density in humans as a result of a prolonged myelination may therefore structure risk for myelin degeneration and dysfunction. Evolutionary considerations for the role of prolonged cortical myelination as a risk factor for demyelinating disease are particularly pertinent given that genetics and autoimmune deficiency hypotheses fail to explain many cases of demyelinating disease. As has been argued, diseases such as multiple sclerosis cannot be accounted for by autoimmune deficiency alone, but strongly imply the influence of flawed developmental processes in disease pathogenesis. Therefore, the role of the human-specific prolonged period of cortical myelination is an important evolutionary consideration in the pathogenesis of demyelinating disease.

Prognosis depends on the condition itself. Some conditions such as multiple sclerosis depend on the subtype of the disease and various attributes of the patient such as age, sex, initial symptoms and the degree of disability the patient experiences. Life expectancy in Multiple sclerosis patients is 5 to 10 years lower than unaffected people. MS is an inflammatory demyelinating disease of the

central nervous system (CNS) that develops in genetically susceptible individuals after exposure to unknown environmental trigger(s). The bases for MS are unknown but are strongly suspected to involve immune reactions against autoantigens, particularly myelin proteins. The most accepted hypothesis is that dialogue between T-cell receptors and myelin antigens leads to an immune attack on the myelin-oligodendrocyte complex. These interactions between active T cells and myelin antigens provoke a massive destructive inflammatory response and promotes continuing proliferation of T and B cells and macrophage activation, which sustains secretion of inflammatory mediators. Other conditions such as central pontine myelinolysis have about a third of patients recover and the other two thirds experience varying degrees of disability. There are cases, such as transverse myelitis where the patient can begin recovery as early as 2 to 12 weeks after the onset of the condition.

At the October 23 meeting of the Child Neurology Society, it was a matter of debate whether acute flaccid myelitis would be likely to return the next year. Enteroviruses D68 and A71 tend to cause neurological symptoms more often than other enteroviruses, but have been infrequent causes of colds. It is possible that enteroviruses have been causing acute flaccid myelitis at a very low rate for many years, misdiagnosed as transverse myelitis, and enterovirus 68 simply happened to become more prevalent in the 2014 season.

The CDC had confirmed 538 cases of enterovirus 68 infection in 43 states. The CDC has determined and submitted to GenBank complete or nearly-complete genomic sequences for three known strains of the virus, which are "genetically related to strains of EV-D68 that were detected in previous years in the United States, Europe, and Asia."

While rates of paralytic symptoms appear to be correlated with the number of respiratory infections, in initial anecdotal reports the cases are not clustered within a family or school, suggesting that the paralysis "per se" is not directly contagious, but arises as a very rare complication of the common respiratory infection.

The CDC MMWR report advised, "To prevent infections in general, persons should stay home if they are ill, wash their hands often with soap and water, avoid close contact (such as touching and shaking hands) with those who are ill, and clean and disinfect frequently touched surfaces."

Unlike polio, acute flaccid myelitis can not currently be prevented with a vaccine.

Neuroborreliosis, also known as Lyme neuroborreliosis (LNB), is a disorder of the central nervous system. A neurological manifestation of Lyme disease, neuroborreliosis is caused by a systemic infection of spirochetes of the genus "Borrelia." Symptoms of the disease include erythema migrans and flu-like symptoms. The microbiological progression of the disease is similar to that of neurosyphilis, another spirochetal infection.

Originally found in neuromyelitis optica, this autoantibody has been associated with other conditions. Its current spectrum is as following:

- Seropositive Devic's disease, according to the diagnostic criteria described above

- Limited forms of Devic's disease, such as single or recurrent events of longitudinally extensive myelitis, and bilateral simultaneous or recurrent optic neuritis

- Asian optic-spinal MS - this variant can present brain lesions like MS.

- Longitudinally extensive myelitis or optic neuritis associated with systemic autoimmune disease

- Optic neuritis or myelitis associated with lesions in specific brain areas such as the hypothalamus, periventricular nucleus, and brainstem

- Some cases of tumefactive multiple sclerosis

Transverse myelitis is a neurological condition in which the spinal cord is inflamed. The inflammation damages nerve fibers, and causes them to lose their myelin coating leading to decreased electrical conductivity in the central nervous system. "Transverse" implies that the inflammation extends across the entire width of the spinal cord. Partial transverse myelitis and partial myelitis are terms used to define inflammation of the spinal cord that affects part of the width of the spinal cord.

The list of these diseases depends of the author, but usually are included:

- multiple sclerosis, normally defined by the dissemination in time and space of demyelinating lesions, with two (or sometimes three) clinical presentations:

- Relapsing-Onset multiple sclerosis, the most known and extended variant, normally consisting of two distinct clinical phases (Remitent-Recidivant, RRMS, and Secondary Progressive, SPMS)

- Progressive-Onset MS, most known as Primary progressive MS including a special genetic variant named rapidly progressive multiple sclerosis.

- Optic-spinal MS, or opticospinal, clinical and pathological variant of multiple sclerosis which often include visual symptoms and have a more severe course than typical MS. Though multiple scars (scleroses) are present in CNS, and they comply with the dissemination criteria, and sometimes is classified as clinically definite multiple sclerosis, currently is considered outside the scope of Multiple Sclerosis and inside the scope of Devic's disease, though it is uncertain if this applies to all cases. Also a variant affecting mainly the spinal cord and the cortex has been proposed

- Neuromyelitis optica (NMO), and its associated "spectrum of disorders" (NMOSD), currently considered a common syndrome for at least three separated diseases:, mainly produced by AQP4 autoimmune channelopathy, though other variants exists, some with anti-MOG and some others idiopathic. Some researchers think that there could exist an overlapping between Anti-NMDA receptor encephalitis cases and neuromyelitis optica or acute disseminated encephalomyelitis.

- Anti-MOG associated spectrum, often clinically presented as an anti-MOG autoimmune encephalomyelitis, but can also appear as negative NMO or atypical multiple sclerosis

- CRION (Chronic relapsing inflammatory optic neuritis): A distinct clinical entity from other inflammatory demyelinating diseases including multiple sclerosis (MS), neuromyelitis optica-immunoglobulin G (NMO-IgG) spectrum disease, and idiopathic relapsing optic neuritis.

- Acute disseminated encephalomyelitis or ADEM, a closely related disorder in which a known virus or vaccine triggers autoimmunity against myelin.

- Acute hemorrhagic leukoencephalitis, possibly a variant of Acute disseminated encephalomyelitis

- Balo concentric sclerosis, an unusual presentation of plaques forming concentrenic circles, which can sometimes get better spontaneously.

- Schilder disease or diffuse myelinoclastic sclerosis: is a rare disease that presents clinically as a pseudotumoural demyelinating lesion; and is more common in children.

- Marburg multiple sclerosis, an aggressive form, also known as malignant, fulminant or acute MS.

- Tumefactive multiple sclerosis: lesions whose size is more than 2 cm, with mass effect, oedema and/or ring enhancement

- Solitary sclerosis: This variant has been recently proposed (2012) by Mayo Clinic researches. though it was also reported by other groups more or less at the same time. It is defined as isolated demyelinating lesions which produce a progressive myelopathy similar to primary progressive MS, and is currently considered a synonym for tumefactive multiple sclerosis.

Some inflammatory conditions are associated with the presence of scleroses in the CNS. Optic neuritis (monophasic and recurrent) and Transverse myelitis (monophasic and recurrent)

As MS is an active field for research, the list is not closed or definitive. For example, some diseases like Susac's syndrome (MS has an important vascular component), leukoaraiosis, myalgic encephalomyelitis (aka chronic fatigue syndrome) or autoimmune variants of peripheral neuropathies like Guillain–Barré syndrome or progressive inflammatory neuropathy could be included assuming the autoimmune model. Also Leukodystrophy (which see) and its sub-conditions: Adrenoleukodystrophy and Adrenomyeloneuropathy could be in the list. Venous induced demyelination has also been proposed as a hypothetical MS variant produced by CCSVI.

Recent research has identified some possible new variants, like the possibility to separate primary progressive MS, PPMS, after recent findings seem to point that it is pathologically a very different disease.

Also an OPA1 variant and aKIR4.1 multiple sclerosis variant was reported in 2012 and later reported again, which could be considered a different disease (as Devic disease did before), and can represent up to a 47% of the MS cases. Finally, there exist some reports of an aquaporine-related multiple sclerosis, related to vegetal aquaporine proteins.

In the US, neuroborreliosis is typically treated with intravenous antibiotics which cross the blood–brain barrier, such as penicillins, ceftriaxone, or cefotaxime. One relatively small randomized controlled trial suggested ceftriaxone was more effective than penicillin in the treatment of neuroborreliosis. Small observational studies suggest ceftriaxone is also effective in children. The recommended duration of treatment is 14 to 28 days.

Several studies from Europe have suggested oral doxycycline is equally as effective as intravenous ceftriaxone in treating neuroborreliosis. Doxycycline has not been widely studied as a treatment in the US, but antibiotic sensitivities of prevailing European and US isolates of "Borrelia burgdorferi" tend to be identical. However, doxycycline is generally not prescribed to children due to the risk of bone and tooth damage.

Discreditied or doubtful treatments for neuroborreliosis include:

- Malariotherapy

- Hyperbaric oxygen therapy

- Colloidal silver

- Injections of hydrogen peroxide and bismacine

Myelopathy describes any neurologic deficit related to the spinal cord. When due to trauma, it is known as (acute) spinal cord injury. When inflammatory, it is known as myelitis. Disease that is vascular in nature is known as vascular myelopathy. The most common form of myelopathy in human, "cervical spondylotic myelopathy (CSM)", is caused by arthritic changes (spondylosis) of the cervical spine, which result in narrowing of the spinal canal (spinal stenosis) ultimately causing compression of the spinal cord. In Asian populations, spinal cord compression often occurs due to a different, inflammatory process affecting the posterior longitudinal ligament.

There are disturbances in sensory nerves and motor nerves and dysfunction of the autonomic nervous system at the level of the lesion or below. Therefore, the signs and symptoms depend on the area of spine involved:

- Cervical: If the upper cervical cord is involved, all four limbs may be involved and there is risk of respiratory paralysis (cervical nerve segments C3, 4, 5 innervate the abdominal diaphragm). Lesions of the lower cervical (C5–T1) region will cause a combination of upper and lower motor neuron signs in the upper limbs, and exclusively upper motor neuron signs in the lower limbs. Cervical lesions account for about 20% of cases.

- Thoracic: A lesion of the thoracic spinal cord (T1–12) will produce upper motor neuron signs in the lower limbs, presenting as a spastic diplegia. This is the most common location of the lesion,

Although there is sometimes a preceding viral infection, or skin or eye trauma, the exact underlying initiator of VKH disease remains unknown. However, VKH is attributed to aberrant T-cell-mediated immune response directed against self-antigens found on melanocytes. Stimulated by interleukin 23 (IL-23), T helper 17 cells and cytokines such as interleukin 17 (IL-17) appear to target proteins in the melanocyte.

VKC is thought to be an allergic disorder in which IgE mediated mechanism play a role. Such patients often give family history of other atopic diseases such as hay fever, asthma or eczema, and their peripheral blood shows eosinophilia and increased serum IgE levels.

The treatment and prognosis of myelopathy depends on the underlying cause: myelopathy caused by infection requires medical treatment with pathogen specific antibiotics. Similarly, specific treatments exist for multiple sclerosis, which may also present with myelopathy. As outlined above, the most common form of myelopathy is secondary to degeneration of the cervical spine. Newer findings have challenged the existing controversy with respect to surgery for cervical spondylotic myelopathy by demonstrating that patients benefit from surgery.

Affected individuals are typically 20 to 50 years old. The female to male ratio is 2:1. By definition, there is no history of either surgical or accidental ocular trauma. VKH is more common in Asians, Latinos, Middle Easterners, American Indians, and Mexican Mestizos; it is much less common in Caucasians and in blacks from sub-Saharan Africa.

VKH is associated with a variety of genetic polymorphisms that relate to immune function. For example, VKH has been associated with human leukocyte antigens (HLA) HLA-DR4 and DRB1/DQA1, copy-number variations (CNV) of complement component 4, a variant IL-23R locus and with various other non-HLA genes. HLA-DRB1*0405 in particular appears to play an important susceptibility role.

An allergy is an abnormal immune reaction to a harmless antigen.

- Seasonal allergy

- Mastocytosis

- Perennial allergy

- Anaphylaxis

- Food allergy

- Allergic rhinitis

- Atopic dermatitis

Eosinophilia can be idiopathic (primary) or, more commonly, secondary to another disease. In the Western World, allergic or atopic diseases are the most common causes, especially those of the respiratory or integumentary systems. In the developing world, parasites are the most common cause. A parasitic infection of nearly any bodily tissue can cause eosinophilia.

Diseases that feature eosinophilia as a sign include:

- Allergic disorders

- Asthma

- Hay fever

- Drug allergies

- Allergic skin diseases

- Pemphigus

- Dermatitis herpetiformis

- IgG4-related disease

- Parasitic infections

- Addison's disease and stress-induced suppression of adrenal gland function

- Some forms of malignancy

- Acute lymphoblastic leukemia

- Chronic myelogenous leukemia

- Eosinophilic leukemia

- Clonal eosinophilia

- Hodgkin lymphoma

- Some forms of non-Hodgkin lymphoma

- Lymphocyte-variant hypereosinophilia

- Systemic mastocytosis

- Systemic autoimmune diseases

- Systemic lupus erythematosus

- Kimura disease

- Eosinophilic granulomatosis with polyangiitis

- Eosinophilic fasciitis

- Eosinophilic myositis

- Eosinophilic esophagitis

- Eosinophilic gastroenteritis

- Cholesterol embolism (transiently)

- Coccidioidomycosis (Valley fever), a fungal disease prominent in the US Southwest.

- Human immunodeficiency virus infection

- Interstitial nephropathy

- Hyperimmunoglobulin E syndrome, an immune disorder characterized by high levels of serum IgE

- Idiopathic hypereosinophilic syndrome.

- Congenital disorders

- Hyperimmunoglobulin E syndrome

- Omenn syndrome

- Familial eosinophilia

Allergic reactions to drugs are a common cause of eosinophilia, with manifestations ranging from diffuse maculopapular rash, to severe life-threatening drug reactions with eosinophilia and systemic symptoms (DRESS). Drugs that have been shown to cause DRESS are aromatic anticonvulsants and other antiepileptics, sulfonamides, allopurinol, nonsteroidal anti-inflammatory drugs (NSAIDs), some antipsychotics such as risperidone, and certain antibiotics. Phenibut, an analogue of the neurotransmitter GABA, has also been implicated in high doses. The reaction which has been shown to be T-cell mediated may also cause eosinophilia-myalgia syndrome.

Vernal keratoconjunctivitis (VKC) or spring catarrh is a recurrent, bilateral, and self-limiting inflammation of conjunctiva, having a periodic seasonal incidence.

An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways:

- By the component(s) of the immune system affected

- By whether the immune system is overactive or underactive

- By whether the condition is congenital or acquired

According to the International Union of Immunological Societies, more than 150 primary immunodeficiency diseases (PIDs) have been characterized. However, the number of acquired immunodeficiencies exceeds the number of PIDs.

It has been suggested that most people have at least one primary immunodeficiency. Due to redundancies in the immune system, though, many of these are never detected.