In all cases of suspected NEH, a skin biopsy should be performed, because the clinical symptoms are non specific, but the histopathological findings on the biopsy are specific. The biopsy shows characteristic changes of the eccrine glands, the major sweat glands of the body.

In NEH, eccrine gland necrosis, and neutrophils surroundings the eccrine glands, are typical findings on biopsy. If the chemotherapy has recently been administered, chemotherapy induced neutropenia may be present, and, as a result, the neutrophils may be absent. But the other characteristic finding, i.e. eccrine gland necrosis, can still be seen. A vacuolar interface dermatitis also is visible in glands and ducts, along with necrosis of the lining cells.

In addition, in patients receiving chemotherapy, keratinocyte atypia can be seen.

A single case report suggested that oral dapsone may be useful for prevention. However, the efficacy of oral dapsone as prevention has not been demonstrated very clearly until now.

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.

Studies show a moderate neutrophilia (less than 50%), elevated ESR (greater than 30 mm/h) (90%), and a slight increase in alkaline phosphatase (83%). Skin biopsy shows a papillary and mid-dermal mixed infiltrate of polymorphonuclear leukocytes with nuclear fragmentation and histiocytic cells. The infiltrate is predominantly perivascular with endothelial-cell swelling in some vessels, but vasculitic changes (blood clots; deposition of fibrin, complement, or immunoglobulins within the vessel walls; red blood cell extravasation;inflammatory infiltration of vascular walls) are absent in early lesions.

Perivasculitis occurs secondarily, because of cytokines released by the lesional neutrophils. True transmural vasculitis is not an expected finding histopathologically in SS.

Pemphigus is a group of autoimmune blistering diseases that may be classified into the following types:

The clinical differential diagnosis includes pyoderma gangrenosum, infection, erythema multiforme, adverse drug reactions, and urticaria. Recurrences are common and affect up to one third of patients.

The Sartorius staging system is more sophisticated than Hurley's. Sartorius "et al." suggested that the Hurley system is not sophisticated enough to assess treatment effects in clinical trials during research. This classification allows for better dynamic monitoring of the disease severity in individual patients. The elements of this staging system are:

- Anatomic regions involved (axilla, groin gluteal, or other region or inframammary region left or right)

- Number and types of lesions involved (abscesses, nodules, fistulas [actually sinuses], scars, points for lesions of all regions involved)

- The distance between lesions, in particular the longest distance between two relevant lesions (i.e., nodules and fistulas in each region or size if only one lesion present)

- The presence of normal skin in between lesions (i.e., are all lesions clearly separated by normal skin?)

Points are accumulated in each of the above categories, and added to give both a regional and total score. In addition, the authors recommend adding a visual analog scale for pain or using the dermatology life quality index (DLQI, or the Skindex) when assessing HS.

Pemphigus defines a group of autoimmune interepithelial blistering diseases that are characterized by loss of normal cell-cell adhesion (acantholysis), and by the presence of pathogenic (predominantly IgG) autoantibodies reacting against epithelial adhesion molecules. Pemphigus is further divided in two major subtypes: pemphigus vulgaris (PV) and pemphigus foliaceus (PF). However, several other disorders such as IgA pemphigus, IgE pemphigus, pemphigus herpetiformis, drug induced pemphigus, Senear Usher syndrome and endemic pemphigus foliaceus exist;recognized by a dermatologist from the appearance and distribution of the skin lesions. It is also commonly diagnosed by specialists practicing otolaryngology- head and neck surgery, periodontists, oral and maxillofacial surgeons and eye doctors, as lesions can affect the eyes and mucous membrane of the oral cavity. Intraorally it resembles the more common diseases lichen planus and mucous membrane pemphigoid. Definitive diagnosis requires examination of a skin or mucous membrane biopsy by a dermatopathologist or oral pathologist. The skin biopsy is taken from the edge of a blister, prepared for histopathology and examined with a microscope. The pathologist looks for an intraepidermal vesicle caused by the breaking apart of epidermal cells (acantholysis). Thus, the superficial (upper) portion of the epidermis sloughs off, leaving the bottom layer of cells on the "floor" of the blister. This bottom layer of cells is said to have a "tombstone appearance".

Definitive diagnosis also requires the demonstration of anti-desmoglein autoantibodies by direct immunofluorescence on the skin biopsy. These antibodies appear as IgG deposits along the desmosomes between epidermal cells, a pattern reminiscent of chicken wire. Anti-desmoglein antibodies can also be detected in a blood sample using the ELISA technique.

This is historically the first classification system proposed, and is still in use for the classification of patients with skin/dermatologic diseases (i.e., psoriasis, HS, acne). Hurley separated patients into three groups based largely on the presence and extent of cicatrization and sinuses. It has been used as a basis for clinical trials in the past and is a useful basis to approach therapy for patients. These three stages are based on Hurley's staging system, which is simple and relies on the subjective extent of the diseased tissue the patient has. Hurley's three stages of hidradenitis suppurativa are:

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.

The differential diagnosis includes oral lichen planus, erythematous candidiasis, leukoplakia, lupus erythematosus, glossitis, and chemical burns. Atrophic glossitis is usually distinguished from benign migratory glossitis on the basis of the migrating pattern of the lesions and the presence of a whitish border, features which are not present in atrophic glossitis, which instead shows lesions which enlarge rather than migrate. Rarely, blood tests may be required to distinguish from glossitis associated with anemia or other nutritional deficiencies. Since the appearance and the history of the condition (i.e. migrating areas of depapillation) are so striking, there is rarely any need for biopsy. When biopsy is taken, the histopathologic appearance is quite similar to psoriasis:

- Hyperparakeratosis.

- Acanthosis.

- Subepithelial T lymphocyte inflammatory infiltrate.

- Migration of neutrophilic granulocytes into the epithelial layer, which may create superficial microabscesses, similar to the Munro's microabscesses described in pustular psoriasis.

CRMO/CNO is a diagnosis of exclusion. This means that other diseases must be ruled out before the diagnosis can be made. Generally, many tests are required, such as blood tests, x-rays, bone scans, MRI and often a bone biopsy.

The Mayo Clinic suggests the following: antibiotics (generally the lowest side effect profile compared to other treatments); corticosteroids (e.g., prednisone); but corticosteroids have many side effects, including "moon face" for the duration of the medication's trial usage, as well as unwanted hair growth for females and/or osteoporosis with long-term use. Tumor necrosis factor (TNF)-alpha inhibitors like infliximab (Remicade) and adalimumab (Humira) have shown promise for some, but they should probably be considered a third-line treatment, as treatment is associated with increased risk of infection, heart failure and certain cancers. Surgery is also available for those overwhelmed by the condition, but it will not cure the condition, just relieve the skin-related issues for a while. The disease is pernicious and is almost always guaranteed to return, if not in the same spot where the surgery was performed.

Some products for adult acne may help relieve some symptoms for hidradenitis sufferers, although there is no guarantee it will work in all or even most individuals. Birth control Medication may relieve some symptoms for women; there is a hormonal treatment for men as well but that has not proven to be safe or effective as of yet.

Alternative treatments include alpha hydroxy acids (naturally available in small amounts in citrus fruits), Azelaic acid, and zinc. It is not thought that they are as effective as standard medical treatment but they tend to have less side effects. Some suggest tea tree oil and a specific strain of brewer's yeast, called CBS 5926. However, the former can cause contact dermatitis for some as well as breast development in teenage boys and should not be used if one suffers from rosacea as well due to it making the symptoms of that strand of acne worse; the latter (CBS 5962) can cause migraines and intestinal issues for some. None of these have been formally tested by the FDA so beware the risk you take when you forgo traditional Western medicine for herbal supplements.

Syringomas can often be diagnosed clinically based on presentation, distribution patterns over the body, lack of associated symptoms and family history. A definitive diagnosis requires a skin biopsy to allow the tissue to be examined under a microscope. Histologically, syringomas have a characteristic comma ("tadpole") shaped tail of dilated, cystic eccrine ducts.

The condition may disappear over time, but it is impossible to predict if or when this may happen.

A scalp biopsy is essential for the diagnosis of cicatricial alopecia and is the necessary first step, as it can be hard to know the diagnosis for sure without a biopsy. Findings of the scalp biopsy, including the type of inflammation present, location and amount of inflammation, and other changes in the scalp, are necessary to diagnose the type of cicatricial alopecia, to determine the degree of activity, and to select appropriate therapy.

Clinical evaluation of the scalp is also important. Symptoms of itching, burning, pain, or tenderness usually signal ongoing activity. Signs of scalp inflammation include redness, scaling, and pustules. However, in some cases there are few symptoms or signs and only the scalp biopsy demonstrates the active inflammation. The overall extent and pattern of hair loss is noted and sometimes photographed for future comparison. A hair "pull test" is performed to see if growing, or "anagen", where hairs are pulled out easily. The pulled hairs are mounted on a slide and the hair bulbs are viewed with a light microscope to determine how many are growing hairs and how many are resting hairs. In addition, if pustules are present, cultures are taken to identify which microbes, if any, may be contributing to the inflammation. A thorough evaluation that includes all of these parameters is important in diagnosing a cicatricial alopecia and in identifying features in individual patients that will help the selection of therapy.

New diagnostic techniques, such as trichoscopy may be used for non-invasive differential diagnosis of cicatricial alopecia.

Diagnosis and treatment of cicatricial alopecias is often challenging. For this reason, it is helpful to be evaluated by a dermatologist with a special interest or expertise in scalp and hair disorders, and who is familiar with current diagnostic methods and therapies.

Prognosis will depend on your child's individual disease and response to treatment. It is best to discuss the prognosis with your child's pediatric rheumatologist.

Painful red swelling of the hands and feet in a patient receiving chemotherapy is usually enough to make the diagnosis. The problem can also arise in patients after bone marrow transplants, as the clinical and histologic features of PPE can be similar to cutaneous manifestations of acute (first 3 weeks) graft-versus-host disease. It is important to differentiate PPE, which is benign, from the more dangerous graft-versus-host disease. As time progresses, patients with graft-versus-host disease progress to have other body parts affected, while PPE is limited to hands and feet. Serial biopsies every 3 to 5 days can also be helpful in differentiating the two disorders (Crider et al., 1986).

The physical examination of the skin and its appendages, as well as the mucous membranes, forms the cornerstone of an accurate diagnosis of cutaneous conditions. Most of these conditions present with cutaneous surface changes termed "lesions," which have more or less distinct characteristics. Often proper examination will lead the physician to obtain appropriate historical information and/or laboratory tests that are able to confirm the diagnosis. Upon examination, the important clinical observations are the (1) morphology, (2) configuration, and (3) distribution of the lesion(s). With regard to morphology, the initial lesion that characterizes a condition is known as the "primary lesion," and identification of such a lesions is the most important aspect of the cutaneous examination. Over time, these primary lesions may continue to develop or be modified by regression or trauma, producing "secondary lesions." However, with that being stated, the lack of standardization of basic dermatologic terminology has been one of the principal barriers to successful communication among physicians in describing cutaneous findings. Nevertheless, there are some commonly accepted terms used to describe the macroscopic morphology, configuration, and distribution of skin lesions, which are listed below.

Hidradenitis is any disease in which the histologic abnormality is primarily an inflammatory infiltrate around the eccrine glands. This group includes neutrophilic eccrine hidradenitis and recurrent palmoplantar hidradenitis.

It can also be defined more generally as an inflammation of sweat glands.

Hidradenitis suppurativa is a chronic cutaneous condition originally thought to be primarily characterized by suppurative inflammation of the apocrine sweat glands. However, recent evidence supports that the primary event is follicular hyperkeratosis and obstruction.

Reactive neutrophilic dermatoses are a spectrum of conditions mediated by neutrophils, and typically associated with underlying diseases, such as inflammatory bowel disease and hematologic malignancy.

Conditions considered to be reactive neutrophilic dermatoses include:

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

The majority (90%) of cases have not had detectable cytogenetic abnormalities. Most importantly, the Philadelphia chromosome and other BCR/ABL fusion genes are not detected.

The cooling of hands and feet during chemotherapy may help prevent PPE (Baack and Burgdorf, 1991; Zimmerman et al., 1995). Support for this and a variety of other approaches to treat or prevent acral erythema comes from small clinical studies, although none has been proven in a randomised controlled clinical trial of sufficient size.

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.