There are seven types of attacks. Ninety percent of all patients have their first attack before they are 18 years old. All develop over 2–4 hours and last anywhere from 6 hours to 4 days. Most attacks involve fever.

1. Abdominal attacks, featuring abdominal pain, affect the whole abdomen with all signs of peritonitis (inflammation of abdominal lining), and acute abdominal pain like appendicitis. They occur in 95% of all patients and may lead to unnecessary laparotomy. Incomplete attacks, with local tenderness and normal blood tests, have been reported.

2. Joint attacks mainly occur in large joints, especially in the legs. Usually, only one joint is affected. 75% of all FMF patients experience joint attacks.

3. Chest attacks include pleuritis (inflammation of the pleura) and pericarditis (inflammation of the pericardium). Pleuritis occurs in 40% of patients and makes it difficult to breathe or lie flat, but pericarditis is rare.

4. Scrotal attacks due to inflammation of the tunica vaginalis occurs in up to 5% and may be mistaken for acute scrotum (i.e. testicular torsion).

5. Myalgia (rare in isolation)

6. Erysipeloid (a skin reaction on the legs, rare in isolation)

7. Fever without any of the other symptoms listed above (25%)

AA-amyloidosis with kidney failure is a complication and may develop without overt crises. AA amyloid protein is produced in very large quantities during attacks, and at a low rate between them, and accumulates mainly in the kidney, as well as the heart, spleen, gastrointestinal tract, and thyroid.

There appears to be an increase in the risk for developing particular vasculitis-related diseases (e.g. Henoch–Schönlein purpura), spondylarthropathy, prolonged arthritis of certain joints and protracted myalgia.

HIDS is one of a number of periodic fever syndromes. It is characterised by attacks of fever, arthralgia, skin lesions including cyclical mouth ulcers, and diarrhea. Laboratory features include an acute phase response (elevated CRP and ESR) and markedly elevated IgD (and often IgA), although cases with normal IgD have been described.

It has mainly been described in the Netherlands and France, although the international registry includes a number of cases from other countries.

The differential diagnosis includes fever of unknown origin, familial Mediterranean fever (FMF) and familial Hibernian fever (or TNFα reception associated periodic syndrome/TRAPS).

Hyperimmunoglobulinemia D with recurrent fever (HIDS) is a periodic fever syndrome originally described in 1984 by the internist Jos van der Meer, then at Leiden University Medical Centre. No more than 300 cases have been described worldwide.

TNF receptor associated periodic syndrome presents with the following signs and symptoms:

- Episodic fever

- Erythrocyte sedimentation rate(increased)

- Pericarditis

- Splenomegaly

- Uveitis

- Vertigo

Muckle–Wells syndrome (MWS), also known as urticaria-deafness-amyloidosis syndrome (UDA), is a rare autosomal dominant disease which causes sensorineural deafness and recurrent hives, and can lead to amyloidosis. Individuals with MWS often have episodic fever, chills, and joint pain. As a result, MWS is considered a type of periodic fever syndrome. MWS is caused by a defect in the CIAS1 gene which creates the protein cryopyrin. MWS is closely related to two other syndromes, familial cold urticaria and neonatal onset multisystem inflammatory disease—in fact, all three are related to mutations in the same gene and subsumed under the term cryopyrin-associated periodic syndromes (CAPS).

The key symptoms of PFAPA are those in its name: periodic high fever at intervals of about 3–5 weeks, as well as aphthous ulcers, pharyngitis and/or adenitis. In between episodes, and even during the episodes, the children appear healthy. At least 6 months of episodes. Diagnosis requires recurrent negative throat cultures and that other causes (such as EBV, CMV, FMF) be excluded.

Erythema infectiosum or fifth disease is one of several possible manifestations of infection by parvovirus B19.

The name "fifth disease" comes from its place on the standard list of rash-causing childhood diseases, which also includes measles (1st), scarlet fever (2nd), rubella (3rd), Dukes' disease (4th, however is no longer widely accepted as distinct) and roseola (6th).

TNF receptor associated periodic syndrome (also known as TRAPS,) is a periodic fever syndrome associated with mutations in a receptor for the molecule tumor necrosis factor (TNF) that is inheritable in an autosomal dominant manner. Individuals with TRAPS have episodic symptoms such as recurrent high fevers, rash, abdominal pain, joint/muscle aches and puffy eyes.

The chronic inflammation present in MWS over time can lead to deafness. In addition, the prolonged inflammation can lead to deposition of proteins in the kidney, a condition known as amyloidosis.

Periodic fever, aphthous stomatitis, pharyngitis and adenitis or periodic fever aphthous pharyngitis and cervical adenopathy (PFAPA) syndrome is a medical condition, typically starting in young children, in which high fever occurs periodically at intervals of about 3–5 weeks, frequently accompanied by aphthous-like ulcers, pharyngitis and/or cervical adenitis (cervical lymphadenopathy). The syndrome was described in 1987 and named two years later.

Fifth disease starts with a low-grade fever, headache, rash, and cold-like symptoms, such as a runny or stuffy nose. These symptoms pass, then a few days later the rash appears. The bright red rash most commonly appears in the face, particularly the cheeks. This is a defining symptom of the infection in children (hence the name "slapped cheek disease"). Occasionally the rash will extend over the bridge of the nose or around the mouth. In addition to red cheeks, children often develop a red, lacy rash on the rest of the body, with the upper arms, torso, and legs being the most common locations. The rash typically lasts a couple of days and may itch; some cases have been known to last for several weeks. Patients are usually no longer infectious once the rash has appeared.

Teenagers and adults may present with a self-limited arthritis. It manifests in painful swelling of the joints that feels similar to arthritis. Older children and adults with fifth disease may have difficulty in walking and in bending joints such as wrists, knees, ankles, fingers, and shoulders.

The disease is usually mild, but in certain risk groups it can have serious consequences:

- In pregnant women, infection in the first trimester has been linked to hydrops fetalis, causing spontaneous miscarriage.

- In people with sickle-cell disease or other forms of chronic hemolytic anemia such as hereditary spherocytosis, infection can precipitate an aplastic crisis.

- Those who are immuno-compromised (HIV/AIDS, chemotherapy) may be at risk for complications if exposed.

The syndromes within CAPS overlap clinically, and patients may have features of more than one disorder. In a retrospective cohort of 136 CAPS patients from 16 countries, the most prevalent clinical features were fever (84% of cases, often with concurrent constitutional symptoms such as fatigue, malaise, mood disorders or failure to thrive), skin rash (either urticarial or maculopapular rash; 97% of cases) especially after cold exposure, and musculoskeletal involvement (myalgia, arthralgia, and/or arthritis, or less commonly joint contracture, patellar overgrowth, bone deformity, bone erosion and/or osteolytic lesion; 86% of cases). Less common features included ophthalmological involvement (conjunctivitis and/or uveitis, or less commonly optic nerve atrophy, cataract, glaucoma or impaired vision; 71% of cases), neurosensory hearing loss (42% of cases), neurological involvement (morning headache, papilloedema, and/or meningitis, or less commonly seizure, hydrocephalus or mental retardation; 40% of cases), and AA amyloidosis (4% of cases). Age of onset is typically in infancy or early childhood. In 57% of cases, CAPS had a chronic phenotype with symptoms present almost daily, whereas the remaining 43% of patients experienced only acute episodes. Up to 56% of patients reported a family history of CAPS. Previous studies confirm these symptoms, although the exact reported rates vary.

The age of onset is almost always before 3 months of age. Many infants are born preterm (1/3 cases) and dysmature. The babies are frequently small for dates. The placenta may be abnormal with non-specific inflammation on histology. Umbilical cord anomalies have occasionally been reported. In severe cases, signs in the brain may be detected on prenatal ultrasound.

The presentation is pleiomorphic, making the diagnosis difficult, but the most common features of this disease involve the skin, joints, and central nervous system.

All have a maculopapular urticarial skin rash that is often present at birth (75% cases). It is probably more correctly described as an urticarial-like rash. The presence of the rash varies with time, and biopsy of these skin lesions shows a perivascular inflammatory infiltrate including granulocytes.

In about 35-65% of cases, arthritis occurs. Joint signs are variably expressed and can lead to transient swelling without sequelae between crises, or to unpredictable anomalies of growth cartilage and long bones epiphyses suggestive of a pseudo-tumour. Biopsies reveal hypertrophic cartilage without inflammatory cells. This most commonly affects the large joints (knees, ankles, elbows, and wrists) but may also involve the small joints of the hands and feet. It is usually bilateral and painful. A common and characteristic feature is giant kneecaps. Severe cases may result in contractures (joint deformities).

Most patients eventually have neurological problems. These manifest themselves in three principal ways: chronic meningitis, involvement of both the optic tract and eye, and sensorineural hearing loss. The chronic meningitis presents with the features of chronically raised intracranial pressure: headaches, vomiting, ventriculomegaly, hydrocephalus, macromegaly, cerebral atrophy, and optic atrophy. Some of these features may be evidenced on prenatal ultrasound. In 50% of cases, intellectual deficit occurs. Seizures occur in 25% of cases, but other manifestations are rare. Histological examination shows infiltration of the meninges with polymorphs.

Ocular manifestations occur in 80% of cases and include uveitis (70%), papillary involvement, conjunctivitis, and optical neuritis. If untreated, these may result in blindness (25%). The sensorineural hearing loss occurs in 75%, and tends to be progressive leading to deafness in 20% of cases.

Almost all children are remarkably short and have growth delay. Fever is extremely common but inconstant and is most often mild. Anemia is frequent. Other findings that have been reported include macrocephaly (95%), large fontanelle, prominent forehead, flattening of the nasal bridge (saddleback nose), short and thick extremities, and finger clubbing. The liver and/or spleen may be enlarged. Lymph node enlargement may also be present.

Later in life, secondary amyloidosis may occur. Delayed puberty and secondary amenorrhoea are not uncommon. Hoarseness due to inflammation of the laryngeal cartilage has also been reported.

Cryopyrin-associated periodic syndrome (CAPS) is a group of rare, heterogeneous autoinflammatory disease characterized by interleukin 1β-mediated systemic inflammation and clinical symptoms involving skin, joints, central nervous system, and eyes. It encompasses a spectrum of three clinically overlapping autoinflammatory syndromes including familial cold autoinflammatory syndrome (FCAS, formerly termed familial cold-induced urticaria), the Muckle–Wells syndrome (MWS), and neonatal-onset multisystem inflammatory disease (NOMID, also called chronic infantile neurologic cutaneous and articular syndrome or CINCA) that were originally thought to be distinct entities, but in fact share a single genetic mutation and pathogenic pathway.

Neonatal-onset multisystem inflammatory disease (abbreviated NOMID, also known as chronic infantile neurologic cutaneous and articular syndrome, or CINCA) is a rare genetic periodic fever syndrome which causes uncontrolled inflammation in multiple parts of the body starting in the newborn period. Symptoms include skin rashes, severe arthritis, and chronic meningitis leading to neurologic damage. It is one of the cryopyrin-associated periodic syndromes.

NOMID can result from a mutation in the "CIAS1" gene (also known as "NLRP3" gene), which helps control inflammation. Mutations in this gene also cause familial cold urticaria and Muckle–Wells syndrome. NOMID has been successfully treated with the drug anakinra.

This syndrome is also known as the Prieur–Griscelli syndrome as it was first described by these authors in 1981.

This inherited disease is characterized by violent muscle twitching and substantial muscle weakness or paralysis among affected horses. HYPP is a dominant genetic disorder; therefore, heterozygotes bred to genotypically normal horses have a statistic probability of producing clinically affected offspring 50% of the time.

Horses with HYPP can be treated with some possibility of reducing clinical signs, but the degree that medical treatment helps varies from horse to horse. There is no cure. Horses with HYPP often lose muscle control during an attack.

Some horses are more affected by the disease than others and some attacks will be more severe than others, even in the same horse. Symptoms of an HYPP attack may include:

- Muscle trembling

- Prolapse of the third eyelid — this means that the third eyelid flickers across the eye or covers more of the eye than normal

- Generalized weakness

- Weakness in the hind end — the horse may look as though it is 'dog-sitting'

- Complete collapse

- Abnormal whinny — because the muscles of the voicebox are affected as well as other muscles

- Death — in a severe attack the diaphragm is paralyzed and the horse can suffocate

HYPP attacks occur randomly and can strike a horse standing calmly in a stable just as easily as during exercise. Following an HYPP attack, the horse appears normal and is not in any pain which helps to distinguish it from Equine Exertional Rhabdomyolysis (ER), commonly known as "Azoturia," "Monday Morning Sickness" or "tying up." Horses that are tying up usually suffer attacks in connection with exercise and may take anywhere from 12 hours to several days to recover. Muscle tissue is damaged in an attack of ER, and the horse will be in pain during and following an attack. A blood test will reveal elevations in certain muscle enzymes after an episode of ER and so the two diseases, while superficially similar, are easily distinguished from one another in the laboratory.

Unlike with seizures, horses with HYPP are fully conscious and lucid during an attack. Horses may suffocate during an HYPP attack due to paralysis of the respiratory system. Horses that collapse during an episode are clearly distressed as they repeatedly struggle to get to their feet. If this occurs while the horse is being ridden or otherwise handled, the human handler or rider may be at risk of being injured by the movement of the horse.

Periodic fever syndromes (also known as autoinflammatory diseases or autoinflammatory syndromes) are a set of disorders characterized by recurrent episodes of systemic and organ-specific inflammation. Unlike autoimmune disorders such as systemic lupus erythematosus, in which the disease is caused by abnormalities of the adaptive immune system, patients with autoinflammatory diseases do not produce autoantibodies or antigen-specific T or B cells. Instead, the autoinflammatory diseases are characterized by errors in the innate immune system.

The syndromes are diverse, but tend to cause episodes of fever, joint pains, skin rashes, abdominal pains and may lead to chronic complications such as amyloidosis.

Most autoinflammatory diseases are genetic and present during childhood. The most common genetic autoinflammatory syndrome is familial Mediterranean fever, which causes short episodes of fever, abdominal pain, serositis, lasting less than 72 hours. It is caused by mutations in the MEFV gene, which codes for the protein pyrin.

Pyrin is a protein normally present in the inflammasome. The mutated pyrin protein is thought to cause inappropriate activation of the inflammasome, leading to release of the pro-inflammatory cytokine IL-1β. Most other autoinflammatory diseases also cause disease by inappropriate release of IL-1β. Thus, IL-1β has become a common therapeutic target, and medications such as anakinra, rilonacept, and canakinumab have revolutionized the treatment of autoinflammatory diseases.

However, there are some autoinflammatory diseases that are not known to have a clear genetic cause. This includes PFAPA, which is the most common autoinflammatory disease seen in children, characterized by episodes of fever, aphthous stomatitis, pharyngitis, and cervical adenitis. Other autoinflammatory diseases that do not have clear genetic causes include adult-onset Still's disease, systemic-onset juvenile idiopathic arthritis, Schnitzler syndrome, and chronic recurrent multifocal osteomyelitis. It is likely that these diseases are multifactorial, with genes that make people susceptible to these diseases, but they require an additional environmental factor to trigger the disease.

Another example that shows that autoinflamatory conditions may not be genetic in origin is found in a report published in "Nature" which shows that diet is very important in the development of such diseases. The ingestion levels of highly saturated fats and cholesterol, (high fat diet, HFD) affects the microbiota composition of the gut. Changes in the microbiota induced by a HFD are protective against the susceptibility to develop osteomyelitis (autoimmune disease) as compared with the changes induced by a low-fat diet. The changes in the microbiome of individuals under HFD showed a reduction in "Prevotella" abundance and were accompanied by significantly reduced expression levels of pro-Interleukin-1β in distant neutrophils.

Schnitzler syndrome is a rare disease characterised by chronic hives (urticaria) and periodic fever, bone pain and joint pain (sometimes with joint inflammation), weight loss, malaise, fatigue, swollen lymph glands and enlarged spleen and liver.

The urticarial rash is non-itching in more than half of cases, which is unusual for hives. It is most prominent on the trunk, arms and legs, sparing the palms, soles, head and neck. Associated angioedema has been reported in a few patients. A review of 94 cases found a mean age at onset of 51 years, and only four patients developed symptoms before the age of 35. The cause and disease mechanism of Schnitzler syndrome remain largely unknown.

Schnitzler syndrome is considered an autoinflammatory and autoimmune disorder. Chronic hives and a monoclonal gammopathy have been proposed as the major criteria, while the others represent minor criteria.

Hereditary gelsolin amyloidosis is a cutaneous condition inherited in an autosomal dominant fashion.

The condition was first described in 1969, by the Finnish ophthalmologist Jouko Meretoja, and is also known as Familial amyloid neuropathy type IV, Meretoja syndrome, Hereditary amyloidosis, Finnish type.

The disorder primarily associated with eye, skin and cranial nerve symptoms. It is a form of amyloidosis, where the amyloid complexes are formed from fragments of the protein gelsolin in the plasma, due to a mutation in the GSN gene (c.654G>A or c.654G>T).

Blood tests show a high concentration of specific gamma-globulins (monoclonal gammopathy) of the IgM type. It almost always has light chains of the κ-type. A variant in which IgG is raised has been described, which appears to be ten times as rare. The immunoglobulins may show up in the urine as Bence Jones proteins. Signs of inflammation are often present: these include an increased white blood cell count (leukocytosis) and a raised erythrocyte sedimentation rate and C-reactive protein. There can be anemia of chronic disease. Bone abnormalities can be seen on radiological imaging (often increased density or osteosclerosis) or biopsy.

Because it is such a rare condition (as of September 2014, only 281 cases have been reported), it is important to rule out other conditions which can cause periodic fevers, paraproteins or chronic hives. These include (and are not limited to) autoimmune or autoinflammatory disorders such as adult-onset Still's disease, angioedema, hematological disorders such as lymphoma or monoclonal gammopathy of undetermined significance, other causes of hives, cryoglobulinemia, mastocytosis, chronic neonatal onset multisystem inflammatory disease or Muckle–Wells syndrome.

It is however possible to have more than one rare condition as seen by a patient with Schnitzler's syndrome and cold induced urticaria.

A meeting of experts, including Dr Liliane Schnitzler (then retired) took place in Strasbourg in May 2012 and drew up diagnostic criteria known as the "Strasbourg Criteria". These included two obligate criteria (chronic urticarial rash and monoclonal IgM or IgG) and several minor criteria; a definite diagnosis requires the two obligate criteria and two minor criteria if IgM, three if IgG; a probable diagnosis requires the two obligate criteria and one (IgM) or two (IgG) minor criteria.

Although much less publicized, hyperkalemic periodic paralysis has been observed in humans. In humans the disorder causes episodes of extreme muscle weakness, with attacks often beginning in infancy. Depending on the type and severity of the HyperKPP, it can increase or stabilize until the fourth or fifth decade where attacks may cease, decline, or, depending on the type, continue on into old age. Factors that can trigger attacks include rest after exercise, potassium-rich foods, stress, fatigue, weather changes, certain pollutants (e.g., cigarette smoke) and fasting. Muscle strength often improves between attacks, although many affected people may have increasing bouts of muscle weakness as the disorder progresses (abortive attacks). Sometimes with HyperKPP those affected may experience degrees of muscle stiffness and spasms (myotonia) in the affected muscles. This can be caused by the same things that trigger the paralysis, dependent on the type of myotonia.

Some people with hyperkalemic periodic paralysis have increased levels of potassium in their blood (hyperkalemia) during attacks. In other cases, attacks are associated with normal blood potassium levels (normokalemia). Ingesting potassium can trigger attacks in affected individuals, even if blood potassium levels do not rise in response.

In contrast to HyperKPP, hypokalemic periodic paralysis (noted in humans) refers to loss-of-function mutations in channels that prevent muscle depolarisation and therefore are aggravated by low potassium ion concentrations.

The most common presentation of Milroy Disease is bilateral lower extremity lymphedema, and may also be accompanied by hydrocele.

The most distinctive clinical feature is the absence of overflow tears with emotional crying after age 7 months. This symptom can manifest less dramatically as persistent bilateral eye irritation. There is also a high prevalence of breech presentation. Other symptoms include weak or absent suck and poor tone, poor suck and misdirected swallowing, and red blotching of skin.

Symptoms in an older child with familial dysautonomia might include:

1. Delayed speech and walking

2. Unsteady gait

3. Spinal curvature

4. Corneal abrasion

5. Less perception in pain or temperature with nervous system.

6. Poor growth

7. Erratic or unstable blood pressure.

8. Red puffy hands

9. Dysautonomia crisis: a constellation of symptoms in response to physical and emotional stress; usually accompanied by vomiting, increased heart rate, increase in blood pressure, sweating, drooling, blotching of the skin and a negative change in personality.

Patients typically complain of muscle stiffness that can continue to focal weakness. This muscle stiffness cannot be walked off, in contrast to myotonia congenita. These symptoms are increased (and sometimes induced) in cold environments. For example, some patients have reported that eating ice cream leads to a stiffening of the throat. For other patients, exercise consistently induces symptoms of myotonia or weakness. Typical presentations of this are during squatting or repetitive fist clenching. Some patients also indicate that specific foods are able to induce symptoms of paramyotonia congenita. Isolated cases have reported that carrots and watermelon are able to induce these symptoms. The canonical definition of this disorder precludes permanent weakness in the definition of this disorder. In practice, however, this has not been strictly adhered to in the literature.