Diagnosis is clinical, based on observation. Biopsy is rarely required.

The diagnosis is made clinically, and usually this is clear cut if the lesion is associated with the flange of a denture. Tissue biopsy is not usually indicated before removal of the lesion, since the excises surgical specimen is usually sent for histopathologic examination and the diagnosis is confirmed retrospectively. Rarely, incisional biopsy may be indicated to rule out neoplasia, e.g. in the presence of suspicious ulceration. The appearance may also be confused with pyogenic granuloma.

The excessive tissue is composed of cellular, inflamed fibrous connective tissue. The appearance of an epulis fissuratum microscopically is an overgrowth of cells from the fibrous connective tissue. The epithelial cells are usually hyperkeratotic and irregular, hyperplastic rete ridges are often seen.

Erythema nodosum is diagnosed clinically. A biopsy can be taken and examined microscopically to confirm an uncertain diagnosis. Microscopic examination usually reveals a neutrophilic infiltrate surrounding capillaries that results in septal thickening, with fibrotic changes in the fat around blood vessels. A characteristic microscopic finding is radial granulomas, well-defined nodular aggregates of histiocytes surrounding a stellate cleft.

Additional evaluation should be performed to determine the underlying cause of erythema nodosum. This may include a full blood count, erythrocyte sedimentation rate (ESR), antistreptolysin-O (ASO) titer and throat culture, urinalysis, intradermal tuberculin test, and a chest x-ray. The ESR is typically high, the C-reactive protein elevated, and the blood showing an increase in white blood cells.

The ESR is initially very high, and falls as the nodules of erythema nodosum. The ASO titer is high in cases associated with a streptococcal throat infection. A chest X-ray should be performed to rule out pulmonary diseases, in particular sarcoidosis and Löfgren syndrome.

If the causative factor persists, tissue will become more fibrous over time.

The diagnosis is usually made on the clinical appearance, and tissue biopsy is not usually needed. The histologic picture is one of superficial candidal hyphal infiltration and a polymorphonuclear leukocytic inflammatory infiltrate present in the epithelium. The rete ridges are elongated and hyperplastic (pseudoepitheliomatous hyperplasia, which may be mistaken for carcinoma).

The management of lipodermatosclerosis may include treating venous insufficiency with leg elevation and elastic compression stockings; in some difficult cases, the condition may be improved with the additional use of the fibrinolytic agent, stanozol. Fibrinolytic agents use an enzymatic action to help dissolve blood clots.

Stanozol is injected directly into the affected area, Venous Ablation has also been known to help circulation in patients.

The disease often goes undiagnosed for several years, as it is sometimes not recognized and misdiagnosed as thrush or other problems and not correctly diagnosed until the patient is referred to a specialist when the problem does not clear up.

A biopsy of the affected skin can be done to confirm diagnosis. When a biopsy is done, hyperkeratosis, atrophic epidermis, sclerosis of dermis and lymphocyte activity in dermis are histological findings associated with LS. The biopsies are also checked for signs of dysplasia.

It has been noted that clinical diagnosis of LS can be "almost unmistakable" and therefore a biopsy may not be necessary.

Plasma cell gingivits is rare, and plasma cell cheilitis is very rare. Most people with plasma cell cheilitis have been elderly.

Neutrophilic lobular panniculitis is a cutaneous condition characterized by inflammation of the subcutaneous fat.

Septal panniculitis is a condition of the subcutaneous fat affecting the layer of adipose tissue that lies between the dermis and underlying fascia, of which there are two forms: acute erythema nodosum and chronic erythema nodosum.

Alpha-1 antitrypsin deficiency panniculitis is a panniculitis associated with a deficiency of the α-antitrypsin enzyme.

Histologically plasma cell gingivitis shows mainly plasma cells. The differential diagnosis is with acute leukemia and multiple myeloma. Hence, blood tests are often involved in ruling out other conditions. A biopsy is usually taken, and allergy testing may also be used. The histopathologic appearance is characterized by diffuse, sub-epithelial plasma cell inflammatory infiltration into the connective tissue. The epithelium shows spongiosis. Some consider that plasmoacanthoma (solitary plasma cell tumor) is part of the same spectrum of disease as plasma cell cheilitis.

Atrophic connective tissue panniculitis is a rare condition, and often occurs on the upper or lower extremities.

Erythema nodosum is a form of panniculitis characterised by tender red nodules, 1–10 cm, associated with systemic symptoms including fever, malaise, and joint pain. Nodules may become bluish-purple, yellowing, and green, and subside over a period of 2–6 weeks without ulcerating or scarring. Erythema nodosum is associated with infections, including Hepatitis C, EBV and tuberculosis, Crohn's disease and sarcoidosis, pregnancy, medications including sulfonamides, and some cancers, including Non-Hodgkin lymphoma and pancreatic cancer.

Erythema nodosum is self-limiting and usually resolves itself within 3–6 weeks. A recurring form does exist, and in children it is attributed to repeated infections with streptococcus. Treatment should focus on the underlying cause. Symptoms can be treated with bedrest, leg elevation, compressive bandages, wet dressings, and nonsteroidal anti-inflammatory agents (NSAIDs). NSAIDs are usually more effective at the onset of EN versus with chronic disease.

Potassium iodide can be used for persistent lesions whose cause remains unknown. Corticosteroids and colchicine can be used in severe refractory cases. Thalidomide has been used successfully in the treatment of Erythema nodosum leprosum, and it was approved by the U.S. FDA for this use in July 1998.

There is no official diagnostic criteria for UCTD. Diagnostic testing generally aims to determine whether a patient has a "definite" or "undifferentiated" connective tissue disease.

Treatment may involve smoking cessation and prescription of topical or systemic antifungal medication. Usually the mucosal changes resolve with antifungal therapy, but sometimes the lesion is resistant to complete resolution.

Clinical evaluation and identification of characteristics papules may allow a dermatologist to diagnose Degos disease. The papules have a white center and are bordered with a red ring. After lesions begin to appear, the diagnosis for Degos disease can be supported by histological findings. Most cases will show a wedge-shaped connective tissue necoris in the deep corium. This shape is due to the blockage/occlusion of small arteries.

Individuals may be diagnosed with the benign form if only the papules are present. However, an individual may be diagnosed with the malignant form if involvement of other organs like the lungs, intestine and/or central nervous system occurs. The malignant, or systematic form of this condition may suddenly develop even after having papules present for several years. In order to quickly diagnose this shift to the malignant variant of the disease, it is important for individuals to have consistent follow-up evaluations.In these evaluations, depending on which organs are suspected to be involved, the following procedures and tests may be conducted: skin inspection, brain magnetic resonance tomography, colonoscopy, chest X-ray, and/or abdominal ultrasound.

Weber–Christian disease, also known as relapsing febrile nodular nonsuppurative panniculitis, is a cutaneous condition characterized by recurrent subcutaneous nodules that heal with depression of the overlying skin.

It is type of panniculitis.

It is a rare disease seen in females 30–60 years of age. It is a recurring inflammation of fatty layers of tissue present beneath the skin. Clinical course is characterised by exacerbations and remissions. Lesions are bilaterally symmetrical and are usually seen in the lower legs.

Most patients will maintain a diagnosis of undifferentiated connective tissue disease. However, about one third of UCTD patients will differentiate to a specific autoimmune disease, like rheumatoid arthritis or systemic sclerosis. About 12 percent of patients will go into remission.

Severe vitamin D deficiency has been associated with the progression of UCTD into defined connective tissue diseases. The presence of the autoantibodies anti-dsDNA, anti-Sm, and anti-cardiolipin has been shown to correlate with the development of systemic lupus erythematosus, specifically.

The disease can last for a considerably long time. Occasionally, "spontaneous cure" may ensue, particularly in young girls.

Lichen sclerosus is associated with a higher risk of cancer. Skin that has been scarred as a result of lichen sclerosus is more likely to develop skin cancer. Women with lichen sclerosus may develop vulvar carcinoma. Lichen sclerosus is associated with 3–7% of all cases of vulvar squamous cell carcinoma. In women, it has been reported that 33.6 times higher vulvar cancer risk is associated with LS. A study in men reported that "The reported incidence of penile carcinoma in patients with BXO is 2.6–5.8%".

Good oral hygiene (thorough tooth brushing and flossing and regular professional cleaning and examination) may be helpful to prevent these disorders. Drinking plenty of water and the production of enough saliva, aid in the reduction of bacterial growth. Minimizing irritants or injury in the mouth when possible can aid in the prevention of glossitis. Avoiding excessive use of any food or substance that irritates the mouth or tongue may also help.

PCNA and Ki67 immunoreactivity happens in case of fibroma and peripheral granuloma.

Due to the lack of knowledge around the underlying mechanism of MAP, an effective treatment method has not been developed. Treatment for this condition is symptomatic. However, several treatment methods have been tested and are still being developed as more information regarding the condition is found. Fibrinolytic and immunosuppresive therapeutic regimens were tested and found to be mostly unsuccessful as treatment methods.

After treating conditions comorbid with Degos disease, physicians have recently found improvement in symptoms with the use of eculizumab and treprostinil. Discovered by dermatopathologist, Cynthia Magro, response to eculizumab is often immediate and dramatic, but has been of limited duration and is expensive, needing to be infused every 14 days. Treprostinil use has been reported to result in clearing of gastrointestinal and central nervous system findings as well as clearing of cutaneous lesions, but reports are limited. Treprostinil may be more effective than other vasodilators because it may also increase the population of circulating endothelial cells, allowing angiogenesis.

Many conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square meters, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.

The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum.

The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.

The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source.

Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.