The condition most commonly is located at the junction of the hard and soft palate. However, the condition may arise anywhere minor salivary glands are located. It has also been occasionally reported to involve the major salivary glands. It may be present only on one side, or both sides. The lesion typically is 1–4 cm in diameter.

Initially, the lesion is a tender, erythematous (red) swelling. Later, in the ulcerated stage, the overlying mucosa breaks down to leave a deep, well-circumscribed ulcer which is yellow-gray in color and has a lobular base.

There is usually only minor pain, and the condition is often entirely painless. There may be prodromal symptoms similar to flu before the appearance of the lesion.

Necrotizing sialometaplasia (NS) is a benign, ulcerative lesion, usually located towards the back of the hard palate. It is thought to be caused by ischemic necrosis (death of tissue due to lack of blood supply) of minor salivary glands in response to trauma. Often painless, the condition is self-limiting and should heal in 6–10 weeks.

Although entirely benign and requiring no treatment, due to its similar appearance to oral cancer, it is sometimes misdiagnosed as malignant. Therefore, it is considered an important condition, despite its rarity.

AEN has never been recorded as a one symptom disorder, but instead present by multiple symptoms. The symptoms vary from the severity of the disorder. The most classic sign of AEN is the dark pigmentation of esophageal mucosa in an upper endoscopy, usually viewed as an ulcer or as an infectious disease. Necrosis can be found mostly between the three distals of the esophagus, but stops abruptly at the gastroesophageal junction. The basic and most common symptoms reported are blood in stool and blood in vomiting. Upper gastrointestinal bleeding then is reported, and is very commonly represented in elderly patients. Black or bloody stools and hematemesis account for over three quarters of the case presentations. Abdominal pain, nausea, vomiting, and unstable vital signs are common. A cardiovascular event (such as a heart attack) was reported in ten percent of the total known cases.

Acute esophageal necrosis can only be diagnosed by an upper gastrointestinal endoscopy.

Also called smoker's palatal keratosis, this condition may occur in smokers, especially pipe smokers. The palate appears dry and cracked, and white from keratosis. The minor salivary glands appear as small, red and swollen bumps. It is not a premalignant condition, and the appearance reverses if the smoking is stopped.

The term "necrotizing ulcerative gingivostomatitis" is sometimes used as a synonym of the necrotizing periodontal disease more commonly termed necrotizing ulcerative gingivitis, or a more severe form (also termed necrotizing stomatitis). The term "necrotizing gingivostomatitis" is also sometimes used.

Intestinal Connective tissue abnormality may cause Intestinal Desmosis The absence of the tendinous plexus layer was first described in 1998 by Meier-Ruge. Desmosis is implicated in disturbed gut motility.

Normal peristalsis depends upon the interaction between muscles, nerve cells and tendinous connective tissue. A malfunction of any of these leads to intestinal motility disorders.

Desmosis may be congenital (aplastic form) or acquired (atrophic form).

The "aplastic" form is rare. Typical clinical findings are hypoperistalsis, and pseudo-obstruction. These are found in premature infants, associated with low birth weight. The "atrophic" form is more frequent. Inflammation of the muscularis propria releases enzymes including collagenases which destroy the connective tissue of the bowel wall. Primarily newborns and small children are affected, although this manifestation can also be found in adults. The most common location is the colon with a necrotizing enterocolitis as well as Crohn Disease and diverticulitis. If the taenia are also affected, the disease is defined as complete atrophic desmosis, all other forms without involvement of the taenia are referred to as incomplete. Clinically, patients demonstrate chronic constipation.

As proposed by Giuseppe Martucciello, microscopic diagnosis requires laparoscopic intestinal full-thickness biopsies from colon. Histological findings are absence of the tendinous plexus layer and connective tissue fibers in longitudinal and circular muscle layer.

Initial symptoms of Fournier gangrene include swelling or sudden pain in the scrotum, fever, pallor and generalized weakness. More marked cases are characterized by a foul odor and purulent discharge from the infected tissue. Crepitus has been reported. It begins as a subcutaneous infection. However, soon necrotic patches appear in the overlying skin which later develop into necrosis.

Starts with nonspecific symptoms such as:

- Localized joint pain

- Fever

- Fatigue

- Headaches

- Rashes

- Weight loss

- Diagnosis usually does not happen until the blockage causes deficient blood flow to the extremities or to a stroke.

Livedo reticularis is a common skin finding consisting of a mottled reticulated vascular pattern that appears as a lace-like purplish discoloration of the skin. The discoloration is caused by swelling of the venules owing to obstruction of capillaries by small blood clots. The blood clots in the small blood vessels can be a secondary effect of a condition that increases a person's risk of forming blood clots, including a wide array of pathological and nonpathological conditions . Examples include hyperlipidemia, microvascular hematological or anemia states, nutritional deficiencies, hyper- and autoimmune diseases, and drugs/toxins.

The condition may be normal or related to more severe underlying pathology. Its differential diagnosis is broadly divided into possible blood diseases, autoimmune (rheumatologic) diseases, cardiovascular diseases, cancers, and endocrine disorders. It can usually (in 80% of cases) be diagnosed by biopsy.

It may be aggravated by exposure to cold, and occurs most often in the lower extremities.

The condition's name derives from the Latin "livere" meaning bluish and "reticular" which refers to the net-like appearance.

People usually complain of intense pain that may seem excessive given the external appearance of the skin. People initially have signs of inflammation, fever and a fast heart rate. With progression of the disease, often within hours, tissue becomes progressively swollen, the skin becomes discolored and develops blisters. Crepitus may be present and there may be a discharge of fluid, said to resemble "dish-water". Diarrhea and vomiting are also common symptoms.

In the early stages, signs of inflammation may not be apparent if the bacteria are deep within the tissue. If they are "not" deep, signs of inflammation, such as redness and swollen or hot skin, develop very quickly. Skin color may progress to violet, and blisters may form, with subsequent necrosis (death) of the subcutaneous tissues.

Furthermore, people with necrotizing fasciitis typically have a fever and appear sick. Mortality rates are as high as 73% if left untreated. Without surgery and medical assistance, such as antibiotics, the infection will rapidly progress and will eventually lead to death.

When it affects the groin it is known as Fournier gangrene.

Three or more of the following six criteria must be met:

- Age when disease starts is under 50

- Decreased brachial artery pulse

- Systolic blood pressure differs by more than 10mmHg between arms

- Cramping caused by exercise in the extremities

- Abnormal sounds (through stethoscope) over subclavian arteries or abdominal aorta

- A narrowing or blockage in the aorta, its primary branches, or large arteries as seen through a radiograph of the arteries.

There are no symptoms associated with the lesion itself, although many and varied symptoms and signs may be associated with the underlying cause of immunosuppression. The lesion is a white patch, which almost exclusively occurs on the lateral surfaces of the tongue, although rarely it may occur on the buccal mucosa, soft palate, pharynx or esophagus. The lesion may grow to involve the dorsal surface of the tongue. The texture is vertically corrugated ("hairy") or thickly furrowed and shaggy in appearance.

In most cases skin lesions do not cause symptoms, however itching, burning, or pain may occur.

Frequently reported symptoms include mild fever, muscle pain, joint pain, or an overall feeling of discomfort. Additional symptoms depend on the cause of the vasculitis and if other organ systems are involved. For example, if the vasculitis is a manifestation of Henoch-Schönlein purpura, individuals may also experience abdominal pain or blood in the urine.

Fournier gangrene is a type of necrotizing fasciitis or gangrene affecting the external genitalia and/or perineum. It commonly occurs in older men, but it

can also occur in women and children. It is more likely to occur in diabetics, alcoholics, or those who are immune compromised.

About 1 per 62,500 males are affected a year. Males are affected about 40 times more often than females. It was first described by Baurienne in 1764 and is named after a French venereologist, Jean Alfred Fournier, following five cases he presented in clinical lectures in 1883.

Since alveolar osteitis is not primarily an infection, there is not usually any pyrexia (fever) and cervical lymphadenitis (swollen glands in the neck), and only minimal edema (swelling) and erythema (redness) is present in the soft tissues surrounding the socket.

Signs may include:

- An empty socket, which is partially or totally devoid of blood clot. Exposed bone may be visible or the socket may be filled with food debris which reveals the exposed bone once it is removed. The exposed bone is extremely painful and sensitive to touch. Surrounding inflamed soft tissues may overlie the socket and hide the dry socket from casual examination.

- Denuded (bare) bone walls.

Symptoms may include:

- Dull, aching, throbbing pain in the area of the socket, which is moderate to severe and may radiate to other parts of the head such as the ear, eye, temple and neck. The pain normally starts on the second to fourth day after the extraction, and may last 10–40 days. The pain may be so strong that even strong analgesics do not relieve it.

- Intraoral halitosis (oral malodor).

- Bad taste in the mouth.

Initially red to pink, flat spots (formally, "macules") and raised bumps (formally, "papules") may be seen on the skin.

Once fully developed, the classic appearance is "non-blanching, palpable purpura". This appears as deep red to purple spots that feel raised to the touch. Purpura refers to the red-purple discolored spots, while palpable implies that these spots can be felt as raised from the surrounding skin. Additionally, when gently pressed, the color does not fade to a lighter color ("non-blanching"). The red-purple color of the lesions is due to the inflammation in the blood vessels causing red blood cells to escape into the dermis skin layer.

Small fluid-filled blisters (or "vesicles"), pus-filled bumps resembling a pimple (or "pustules"), or shallow ulcers may also develop but are less common.

The location of skin lesions varies but are most commonly found symmetrically below the waist, primarily on the buttocks and legs. Other distributions include localized areas on the upper body or over several areas of the body.

With treatment, the lesions typically resolve in weeks to months and leave behind flat spots that are darker than the surrounding skin. (see "Postinflammatory hyperpigmentation" on "Hyperpigmentation")

A portion of cases may be persistent or recurrent. This tends to occur when the vasculitis is associated with chronic conditions such as connective tissue diseases.

The primary skin lesion usually starts with a macule that is painless, round and erythematous. Then, it develops into a pustule, and then a bulla with central hemorrhagic focus. The bullae progresses into an ulcer which extends laterally. Finally it becomes a gangrenous ulcer with central black eschar surrounded by erythematous halo.

The lesion may be single or multiple. They are most commonly seen in perineum and under arm pit. However, it can occur in any part of the body.

A wide range of other diseases may cause mouth ulcers. Hematological causes include anemia, hematinic deficiencies, neutropenia, hypereosinophilic syndrome, leukemia, myelodysplastic syndromes, other white cell dyscrasias, and gammopathies. Gastrointestinal causes include celiac disease, Crohn's disease (orofacial granulomatosis), and ulcerative colitis. Dermatological causes include chronic ulcerative stomatitis, erythema multiforme (Stevens-Johnson syndrome), angina bullosa haemorrhagica and lichen planus. Other examples of systemic disease capable of causing mouth ulcers include lupus erythematosus, Sweet syndrome, reactive arthritis, Behçet syndrome, granulomatosis with polyangiitis, periarteritis nodosa, giant cell arteritis, diabetes, glucagonoma, sarcoidosis and periodic fever, aphthous stomatitis, pharyngitis and adenitis.

The conditions eosinophilic ulcer and necrotizing sialometaplasia may present as oral ulceration.

Macroglossia, an abnormally large tongue, can be associated with ulceration if the tongue protrudes constantly from the mouth. Caliber persistent artery describes a common vascular anomaly where a main arterial branch extends into superficial submucosal tissues without a reduction of diameter. This commonly occurs in elderly people on the lip and may be associated with ulceration.

Ecthyma gangrenosum is a type of skin lesion characterized by vesicles or blisters which rapidly evolve into pustules and necrotic ulcers with undermined tender erythematous border. "Ecthyma" means a pus forming infection of the skin with an ulcer, "gangrenosum" means the gangrene or necrosis. It is the pathognomonic of "Pseudomonas aeruginosa" bacteremia. "Pseudomonas aeruginosa" is a gram negative, aerobic, coccobacillus bacterium.

This type of skin lesion was first described in association with "Pseudomonas aeruginosa" by L. Barker in 1897. It was given the name "ecthyma gangrenosum" by Hitschmann and Kreibich.

It mostly occurs in patients with underlying immunocompromised conditions (e.g. Malignancy). Although most cases are found in "Pseudomonas aeruginosa" infection, there are recent reports of this skin lesion associated with other microorganisms, such as "Escherichia coli, Citrobacter freundii, Klebsiella pneumonia", various other Pseudomonas species, and "Morganella morganii."

A number of conditions may cause the appearance of livedo reticularis:

- Cutis marmorata telangiectatica congenita, a rare congenital condition

- Sneddon syndrome – association of livedoid vasculitis and systemic vascular disorders, such as strokes, due to underlying genetic cause

- Idiopathic livedo reticularis – the most common form of livedo reticularis, completely benign condition of unknown cause affecting mostly young women during the winter: It is a lacy purple appearance of skin in extremities due to sluggish venous blood flow. It may be mild, but ulceration may occur later in the summer.

- Secondary livedo reticularis:

- Vasculitis autoimmune conditions:

- Livedoid vasculitis – with painful ulceration occurring in the lower legs

- Polyarteritis nodosa

- Systemic lupus erythematosus

- Dermatomyositis

- Rheumatoid arthritis

- Lymphoma

- Pancreatitis

- Chronic pancreatitis

- Tuberculosis

- Drug-related:

- Adderall (side effect)

- Amantadine (side effect)

- Bromocriptine (side effect)

- Beta IFN treatment, "i.e." in multiple sclerosis

- Livedo reticularis associated with rasagiline

- Methylphenidate and dextroamphetamine-induced peripheral vasculopathy

- Gefitinib

- Obstruction of capillaries:

- Cryoglobulinaemia – proteins in the blood that clump together in cold conditions

- Antiphospholipid syndrome due to small blood clots

- Hypercalcaemia (raised blood calcium levels which may be deposited in the capillaries)

- Haematological disorders of polycythaemia rubra vera or thrombocytosis (excessive red cells or platelets)

- Infections (syphilis, tuberculosis, Lyme disease)

- Associated with acute renal failure due to cholesterol emboli status after cardiac catheterization

- Arteriosclerosis (cholesterol emboli) and homocystinuria (due to Chromosome 21 autosomal recessive Cystathionine beta synthase deficiency)

- Intra-arterial injection (especially in drug addicts)

- Ehlers-Danlos syndrome – connective tissue disorder, often with many secondary conditions, may be present in all types

- Pheochromocytoma

- Livedoid vasculopathy and its association with factor V Leiden mutation

- FILS syndrome (polymerase ε1 mutation in a human syndrome with facial dysmorphism, immunodeficiency, livedo, and short stature)

- Primary hyperoxaluria, oxalosis (oxalate vasculopathy)

- Cytomegalovirus infection (very rare clinical form, presenting with persistent fever and livedo reticularis on the extremities and cutaneous necrotizing vasculitis of the toes)

- Generalized livedo reticularis induced by silicone implants for soft tissue augmentation

- As a rare skin finding in children with Down syndrome

- Idiopathic livedo reticularis with polyclonal IgM hypergammopathy

- CO angiography (rare, reported case)

- A less common skin lesion of Churg-Strauss syndrome

- Erythema nodosum-like cutaneous lesions of sarcoidosis showing livedoid changes in a patient with sarcoidosis and Sjögren's syndrome

- Livedo vasculopathy associated with IgM antiphosphatidylserine-prothrombin complex antibody

- Livedo vasculopathy associated with plasminogen activator inhibitor-1 promoter homozygosity and prothrombin G20210A heterozygosity

- As a first sign of metastatic breast carcinoma (very rare)

- Livedo reticularis associated with renal cell carcinoma (rare)

- Buerger's disease (as an initial symptom)

- As a rare manifestation of Graves hyperthyroidism

- Associated with pernicious anaemia

- Moyamoya disease (a rare, chronic cerebrovascular occlusive disease of unknown cause, characterized by progressive stenosis of the arteries of the circle of Willis leading to an abnormal capillary network and resultant ischemic strokes or cerebral hemorrhages)

- Associated with the use of a midline catheter

- Familial primary cryofibrinogenemia.

Inflammation occurs in the laryngeal, tracheal and bronchial cartilages. Both of these sites are involved in 10% of persons with RP at presentation and 50% over the course of this autoimmune disease, and is more common among females.

The involvement of the laryngotracheobronchial cartilages may be severe and life-threatening; it causes one-third of all deaths among persons with RP.

Laryngeal chondritis is manifested as pain above the thyroid gland and, more importantly, as dysphonia with a hoarse voice or transient aphonia. Because this disease is relapsing, recurrent laryngeal inflammation may result in laryngomalacia or permanent laryngeal stenosis with inspiratory dyspnea that may require emergency tracheotomy as a temporary or permanent measure.

Tracheobronchial involvement may or may not be accompanied with laryngeal chondritis and is potentially the most severe manifestation of RP.

The symptoms consist of dyspnea, wheezing, a nonproductive cough, and recurrent, sometimes severe, lower respiratory tract infections.

Obstructive respiratory failure may develop as the result of either permanent tracheal or bronchial narrowing or chondromalacia with expiratory collapse of the tracheobronchial tree. Endoscopy, intubation, or tracheotomy has been shown to hasten death.

Since dry socket occurs exclusively following a dental extraction, it could be considered both a complication and an iatrogenic condition, but this does not take into account both the reason why the tooth required extraction (i.e., extraction may have been unavoidable due to significant pain and infection) and also the fact that many dry sockets are the result of poor compliance with postoperative instructions, notably refraining from smoking in the days immediately after the procedure.

These conditions are sometimes considered together with the small vessel vasculitides.

Polyarteritis nodosa (PAN). Systemic necrotizing vasculitis and aneurysm formation affecting both medium and small arteries. If only small vessels are affected, it is called microscopic polyangiitis, although it is more associated with granulomatosis with polyangiitis than to classic PAN. At least 3 out of 10 criteria yields sensitivity and specificity of 82 and 87%:

- unexplained weight loss > 4 kg

- livedo reticularis

- testicular pain

- myalgias, weakness

- Abdominal pain, diarrhea, and GI bleeding

- mononeuropathy or polyneuropathy

- new onset diastolic blood pressure > 90 mmHg

- elevated serum BUN (> 40 mg/dL) or serum creatinine (> 1.5 mg/dL)

- hepatitis B infection

- arteriographic abnormalities

- arterial biopsy showing polymorphonuclear cells

Kawasaki disease. Usually in children(age<4), it affects large, medium, and small vessels, prominently the coronary arteries. Associated with a mucocutaneous lymph node syndrome. Diagnosis requires fever lasting five days or more with at least 4 out of 5 criteria:

- bilateral conjunctival injection

- injected or fissured lips, injected pharynx, or strawberry tongue

- erythema of palms/soles, edema of hands/feet, periungual desquamation

- polymorphous rash

- cervical lymphadenopathy (at least one node > 1.5 cm)

Isolated cerebral vasculitis. Affects medium and small arteries over a diffuse CNS area, without symptomatic extracranial vessel involvement. Patients have CNS symptoms as well as cerebral vasculitis by angiography and leptomeningeal biopsy.

Necrotizing granulomas can develop in patients with rheumatoid arthritis, typically manifesting as bumps in the soft tissues around the joints (so-called rheumatoid nodules) or in the lungs.