Necrobiotic xanthogranuloma (also known as "Necrobiotic xanthogranuloma with paraproteinemia") is a multisystem disease that affects older adults, and is characterized by prominent skin findings.

Tracheobronchomegaly is a very rare congenital disorder of the lung primarily characterized by an abnormal widening of the upper airways. The abnormally widened trachea and mainstem bronchi are associated with recurrent lower respiratory tract infection and copious purulent sputum production, eventually leading to bronchiectasis and other respiratory complications.

The incidence of pleural empyema and the prevalence of specific causative microorganisms varies depending on the source of infection (community acquired vs. hospital acquired pneumonia), the age of the patient and host immune status. Risk factors include alcoholism, drug use, HIV infection, neoplasm and pre-existent pulmonary disease. Pleural empyema was found in 0.7% of 3675 patients needing hospitalization for a community acquired pneumonia in a recent Canadian single-center prospective study. A multi-center study from the UK including 430 adult patients with community acquired pleural empyema found negative pleural-fluid cultures in 54% of patients, Streptococcus milleri group in 16%, Staphylococcus aureus in 12%, Streptococcus pneumoniae in 8%, other Streptococci in 7% and anaerobic bacteria in 8%. Given the difficulties in culturing anaerobic bacteria the frequency of the latter (including mixed infections) might be underestimated.

The risk of empyema in children seems to be comparable to adults. Using the United States Kids’ Inpatient Database the incidence is calculated to be around 1.5% in children hospitalized for community acquired pneumonia, although percentages up to 30% have been reported in individual hospitals, a difference which may be explained by an transient endemic of highly invasive serotype or overdiagnosis of small parapneumonic effusions. The distribution of causative organisms does differ greatly from that in adults: in an analysis of 78 children with community acquired pleural empyema, no micro-organism was found in 27% of patients, Streptococcus pneumoniae in 51%, Streptococcus pyogenes in 9% and Staphylococcus aureus in 8%.

Although pneumococcal vaccination dramatically decreased the incidence of pneumonia in children, it did not have this effect on the incidence of complicated pneumonia. It has been shown that the incidence of empyema in children was already on the rise at the end of the 20th century, and that the widespread use of pneumococcal vaccination did not slow down this trend. This might in part be explained by a change in prevalence of (more invasive) pneumococcal serotypes, some of which are not covered by the vaccine, as well a rise in incidence of pneumonia caused by other streptococci and staphylococci. The incidence of empyema seems to be rising in the adult population as well, albeit at a slower rate.

Equine multinodular pulmonary fibrosis is a chronic lung disease of horses. There is evidence that the disease is caused by infection with a gammaherpesvirus, equine herpesvirus 5. The disease affects adult (usually older) horses, causing weight loss and reduced ability to exercise as a result of the formation of nodular lesions in the lungs.

Woodring et al. (1991) suggested the following diagnostic criteria for tracheomegaly in adults based on chest radiography:

- Adult Males: Tracheal transverse diameter > 25 mm and sagittal diameter > 27 mm.

- Adult Females: Tracheal transverse diameter > 21 mm and sagittal diameter > 23 mm.

Steatocystoma simplex, also known as a "simple sebaceous duct cyst" or "solitary steatocystoma", is a cutaneous condition characterized by a skin lesion that occurs with equal frequency in adult women and men, and is typically found on the face, trunk, or extremities.

All patients with empyema require outpatient follow-up with a repeat chest X-ray and inflammatory biochemistry analysis within 4 weeks following discharge. Chest radiograph returns to normal in the majority of patients by 6 months. Patients should of course be advised to return sooner if symptoms redevelop. Long-term sequelae of pleural empyema are rare but include bronchopleural fistula formation, recurrent empyema and pleural thickening, which may lead to functional lung impairment needing surgical decortication.

Approximately 15% of adult patients with pleural infection die within 1 year of the event, although deaths are usually due to comorbid conditions and not directly due to sepsis from the empyema. Mortality in children is generally reported to be less than 3%. No reliable clinical, radiological or pleural fluid characteristics accurately determine patients’ prognosis at initial presentation.

OPA has been found in most countries where sheep are farmed, with the exception of Australia and New Zealand. OPA has been eradicated in Iceland.

No breed or sex of sheep appears to be predisposed to OPA. Most affected sheep show signs at 2 to 4 years of age.

OPA is not a notifiable disease, and therefore it is difficult to assess its prevalence.

Renal cysts and diabetes syndrome (RCAD), also known as MODY 5, is a form of maturity onset diabetes of the young.

HNF1β-related MODY is one of the less common forms of MODY, with some distinctive clinical features, including atrophy of the pancreas and several forms of renal disease. HNF1β, also known as transcription factor 2 (TCF2), is involved in early stages of embryonic development of several organs, including the pancreas, where it contributes to differentiation of pancreatic endocrine Ngn3 cell progenitors from non-endocrine embryonic duct cells. The gene is on chromosome 17q.

The degree of insulin deficiency is variable. Diabetes can develop from infancy through middle adult life, and some family members who carry the gene remain free of diabetes into later adult life. Most of those who develop diabetes show atrophy of the entire pancreas, with mild or subclincal deficiency of exocrine as well as endocrine function.

The non-pancreatic manifestations are even more variable. Kidney and genitourinary malformation and diseases may occur, but inconsistently even within a family, and the specific conditions include a range of apparently unrelated anomalies and processes. The most common genitourinary condition is cystic kidney disease, but there are many varieties even of this. Renal effects begin with structural alterations (small kidneys, renal cysts, anomalies of the renal pelvis and calices), but a significant number develop slowly progressive renal failure associated with chronic cystic disease of the kidneys. In some cases, renal cysts may be detected in utero. Kidney disease may develop before or after hyperglycemia, and a significant number of people with MODY5 are discovered in renal clinics.

With or without kidney disease, some people with forms of HNF1β have had various minor or major anomalies of the reproductive system. Male defects have included epididymal cysts, agenesis of the vas deferens, or infertility due to abnormal spermatozoa. Affected women have been found to have vaginal agenesis, hypoplastic, or bicornuate uterus.

Liver enzyme elevations are common, but clinically significant liver disease is not. Hyperuricaemia and early onset gout have occurred.

Adult blaschkitis is a rare inflammatory skin condition presenting as pruritic papules and vesicles along multiple lines of Blaschko.

Acrospiroma (also known as hidradenoma) is a cutaneous condition, primarily occurring in adult women, that is a form of benign adnexal neoplasm closely related to poroma.

Juvenile xanthogranuloma (JXG) is a form of histiocytosis, classified as "non-Langerhans cell histiocytosis", or more specifically, "type 2".

It is a rare skin disorder that primarily affects children under one year of age but can also be found in older children and adults. It was first described in 1905 by Adamson. In 5% to 17% of people, the disorder is present at birth, but the median age of onset is two years. JXG is a benign idiopathic cutaneous granulomatous tumor and the most common form of non-Langerhans cell histiocytosis (non-LHC). The lesions appear as orange-red macules or papules and are usually located on the face, neck, and upper trunk. They may also appear at the groin, scrotum, penis, clitoris, toenail, palms, soles, lips, lungs, bone, heart, and gastrointestinal tract more rarely. JXG usually manifests with multiple lesions on the head and neck in cases with children under six months of age. The condition usually resolves spontaneously over one to five years. A biopsy of the lesion is critical to confirm the diagnosis.

Ocular JXG manifests in up to 10% of people with JXG and may affect their vision. The presence of JXG in the eye can cause spontaneous hyphema, secondary glaucoma or even blindness. It is most often seen in the iris but may be found on the eyelid, corneoscleral limbus, conjunctiva, orbit, retina, choroid, disc, or optic nerve. Of patients with ocular JXG, 92% are younger than the age of two. Although cutaneous JXG usually disappear spontaneously, ocular lesions rarely improve spontaneously and require treatment. Treatments that have been used include surgical excision, intralesional steroid injection, cryotherapy, and low dose radiotherapy. In the case of a resistant or reoccurring lesion, chemotherapy has been used as a treatment. Ocular JXG is usually unilateral and presents with a tumor, a red eye with signs of uveitis, unilateral glaucoma, spontaneous hyphema or heterochromia iridis. Diagnosing and treating the patient as early as possible contributes to the most positive visual outcome.

Histiocytic disorders like JXG are identified by the cells that make them up. Immunohistochemical analysis is used to discern the immunoreactivity to certain antibodies in these analyses. JXG is a non-LHC disorder which is a varied group of disorders defined by the accumulation of histiocytes that do not meet criteria to be diagnosed as Langerhans cells. JXG is not metastatic and may be present with lipid deposits. JXG is often accompanied with other disorders such as neurofibromatosis type one and juvenile chronic myelogenous leukemia. Juvenile variety xantogranuloma can be distinguished from xanthoma by the spread of the lesion and the lack of lipid abnormalities. Other similar diagnoses include molluscum contagiosum, hemangioma and neurofibroma.

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.

The cause of a pinworm infection is the worm "Enterobius vermicularis". The entire lifecycle — from egg to adult — takes place in the human gastrointestinal tract of a single human host. Cook "et al." (2009) and Burkhart & Burkhart (2005) disagree over the length of this process, with Cook "et al." stating two to four weeks, while Burkhart & Burkhart states that it takes from four to eight weeks.

Pinworm infection cannot be totally prevented under most circumstances. This is due to the prevalence of the parasite and the ease of transmission through soiled night clothes, airborne eggs, contaminated furniture, toys and other objects. Infection may occur in the highest strata of society, where hygiene and nutritional status are typically high. The stigma associated with pinworm infection is hence considered a possible over-emphasis. Counselling is sometimes needed for upset parents that have discovered their children are infected, as they may not realize how prevalent the infection is.

Preventative action revolves around personal hygiene and the cleanliness of the living quarters. The "rate" of reinfection can be reduced through hygienic measures, and this is recommended especially in recurring cases.

The main measures are keeping fingernails short, and washing and scrubbing hands and fingers carefully, especially after defecation and before meals. Under ideal conditions, bed covers, sleeping garments, and hand towels should be changed daily. Simple laundering of clothes and linen disinfects them. Children should wear gloves while asleep, and the bedroom floor should be kept clean. Food should be covered to limit contamination with dust-borne parasite eggs. Household detergents have little effect on the viability of pinworm eggs, and cleaning the bathroom with a damp cloth moistened with an antibacterial agent or bleach will merely spread the still-viable eggs. Similarly, shaking clothes and bed linen will detach and spread the eggs.

Self-healing papular mucinosis is a skin condition caused by fibroblasts producing abnormally large amounts of mucopolysaccharides, and may present in adult and juvenile forms. The juvenile variant is also called self-healing juvenile cutaneous mucinosis.

The infection is most commonly caused by abrasions on different soft tissues through which the bacteria, "Actinobacillus lignieresii," enters. These soft tissues include subcutaneous tissues, the tongue, lymph nodes, lungs, and various tissues in the gastrointestinal tract. The injury results in different forms and locations of the disease depending on the location of the tissue. The commensal bacteria is also commonly found in the oral cavity, gastrointestinal tract, and reproductive tract, sometimes resulting in disease. There are generally one or two cases of actinobacillosis per herd found in adult cows, foals or adult horses, and other similar animals.

Ovine pulmonary adenocarcinoma (OPA), also known as ovine pulmonary adenomatosis, or jaagsiekte, is a chronic and contagious disease of the lungs of sheep and goats. OPA is caused by a retrovirus called jaagsiekte sheep retrovirus (JSRV).

Actinobacillosis is a zoonotic disease caused by Actinobacillus.

It is more commonly associated with animals than with humans.

One of the most common forms seen by veterinarians is mouth actinobacillosis of cattle, due to "Actinobacillus lignieresii". The most prominent symptom is the swelling of the tongue that comes out of the mouth and is very hard at palpation ("wooden tongue").

"Actinobacillus suis" is an important disease of pigs of all ages and can lead to severe morbidity and sudden death.

A prenatal diagnosis was made by Kleijer et al. in 1979 by measuring beta-galactosidase and neuraminidase activities in cultured amniotic fluid cells.

It is associated with cathepsin A.This disease is due to mutations in the CTSA gene which encodes the protective protein/cathepsin A (PPCA). This in turn leads to a secondary deficiency of beta-galactosidase (GLB1) and neuraminidase 1 (NEU1).There are three distinct CTSA isoforms.

Pipecolic acidemia, also called hyperpipecolic acidemia or hyperpipecolatemia, is a very rare autosomal recessive metabolic disorder that is caused by a peroxisomal defect.

Pipecolic acidemia can also be an associated component of Refsum disease with increased pipecolic acidemia (RDPA), as well as other peroxisomal disorders, including both infantile and adult Refsum disease, and Zellweger syndrome.

The disorder is characterized by an increase in pipecolic acid levels in the blood, leading to neuropathy and hepatomegaly.

Infection-related cutaneous conditions may be caused by bacteria, fungi, yeast, viruses, or parasites.

Metagonimiasis is a disease caused by an intestinal trematode, most commonly "Metagonimus yokagawai", but sometimes by "M. takashii" or "M. miyatai". The metagonimiasis-causing flukes are one of two minute flukes called the heterophyids. Metagonimiasis was described by Katsurasa in 1911–1913 when he first observed eggs of "M. yokagawai" in feces (date is disputed in various studies). "M. takahashii" was described later first by Suzuki in 1930 and then "M. Miyatai" was described in 1984 by Saito.

Stained adult fluke causing metagonimiasis

Laryngeal papillomatosis is caused by human papillomavirus (HPV), most frequently by types 6 and 11. The mode of transmission is found to differ depending on age. The disease is typically separated into two forms, juvenile and adult papillomatosis, based on whether it develops before or after 20 years of age. The juvenile form is generally transmitted through contact with a mother’s infected vaginal canal during childbirth. Less is known about transmission in the adult form of this disease, though oral sex has been implicated as a potential mode of transmission. However, it is uncertain whether oral sex would directly transmit the virus or activate the dormant virus that was transmitted at childbirth.

In general, physicians are unsure why only certain people who have been exposed to the HPV types implicated in the disease develop laryngeal papillomatosis. In the case of the juvenile form of the disease, the likelihood of a child born of an infected mother developing laryngeal papillomatosis is low (between 1 in 231 to 1 in 400), even if the mother’s infection is active. Risk factors for a higher likelihood of transmission at childbirth include the first birth, vaginal birth, and teenage mother.