Individuals who smoke or are exposed to smog or other airborne pollutants can develop a condition known as COPD. In this disorder, there is constant irritation of the breathing tubes (trachea) and the small airways. The constant irritation results in excess production of mucus which makes breathing difficult. Frequently, these individuals wake up in the morning with copious amounts of foul smelling mucus and a cough which lasts all day. Wheeze and heavy phlegm are common findings. COPD is a lifelong disorder and there is no cure. Eventually most people develop recurrent pneumonia, lack any type of endurance, and are unable to work productively. One of the ways to avoid chronic bronchitis is to stop or not smoke.

Causes

Esophagitis cannot be spread. However, infections can be spread by those who have infectious esophagitis. Esophagitis can develop due to many causes. GERD is the most common cause of esophagitis because of the backflow of acid from the stomach, which can irritate the lining of the esophagus.

Other causes include:

- Medicines- Can cause esophageal damage that can lead to esophageal ulcers

- Nonsteroidal anti-inflammatory drugs (NSAIDS)-aspirin, naproxen sodium, and ibuprofen. Known to irritate the GI tract.

- Antibiotics- doxycycline and tetracycline

- Quinidine

- Biphosphonates- used to treat osteoporosis

- Steroids

- Potassium chloride

- Chemical injury by alkaline or acid solutions

- Physical injury resulting from nasogastric tubes.

- Alcohol abuse- Can wear down the lining of the esophagus.

- Crohn's disease – a type of IBD and an autoimmune disease that can cause esophagitis if it attacks the esophagus.

- Stress- Can cause higher levels of acid reflux

- Radiation therapy-Can affect the immune system.

- Allergies (food, inhalants)- Allergies can stimulate eosinophilic esophagitis.

- Infection-People with an immunodeficiencies have a higher chance of developing esophagitis.

- Vitamins and supplements (iron, Vitamin C, and potassium)-Supplements and minerals can be hard on the GI tract.

- Vomiting- Acid can irritate esophagus.

- Hernias-A hernia can poke through the diaphragm muscle and can inhibit the stomach acid and food from draining quickly.

- Surgery

Prevention

Since there can be many causes underlying esophagitis, it is important to try to find the cause to help to prevent esophagitis. To prevent reflux esophagitis, avoid acidic foods, caffeine, eating before going to bed, alcohol, fatty meals, and smoking. To prevent drug-induced esophagitis, drink plenty of liquids when taking medicines, take an alternative drug, and do not take medicines while lying down, before sleeping, or too many at one time. Esophagitis is more prevalent in adults and does not discriminate.

One of the most common areas of the body associated with irritation is the vagina. Many women complain of an itch, dryness, or discharge in the perineum at some point in their lives. There are several causes of vaginal irritation including fungal vaginitis (like candida) or trichomoniasis. Often, herpes simplex infection of the mouth or genitalia can be recurrent and prove to be extremely irritating.

Sometimes, the irritation can be of the chronic type and it can be so intense that it also causes painful intercourse. Aside from infections, chronic irritation of the vagina may be related to the use of contraceptives and condoms made from latex. The majority of contraceptives are made of synthetic chemicals which can induce allergies, rash and itching. Sometimes the lubricant used for intercourse may cause irritation.

Another cause of irritation in women is post menopausal vaginitis. The decline in the female sex hormones leads to development of dryness and itching in the vagina. This is often accompanied by painful sexual intercourse. Cracks and tears often develop on outer aspects of the labia which becomes red from chronic scratching. Post menopausal vaginitis can be treated with short term use of vaginal estrogen pessary and use of a moisturizer.

The esophagus is a muscular tube made of both voluntary and involuntary muscles. It is responsible for peristalsis of food. It is about 8 inches long and passes through the diaphragm before entering the stomach. The esophagus is made up of four different layers: serosa, muscularis externa, submucosa, and the mucosa. The mucosa, which is the inner most layer and lining of the esophagus, is composed of stratified squamous epithelium, lamina propria, and muscularis mucosae. At the end of the esophagus is the lower esophageal sphincter, which prevents stomach acid from moving to the esophagus. Sometimes the sphincter allows acid to backflow into the esophagus if it is not strong enough. Esophagitis occurs when there is an infection or irritation to the layers of the esophagus. Infection can be caused by bacteria, viruses, fungi, or diseases that weaken the immune system. Irritation can be caused by GERD, vomiting, surgery, medications, hernias, and radiation injury. Inflammation can cause the esophagus to narrow, which makes swallowing food difficult and may result in food bolus impaction. Irritation from the backflow of acid can cause the feeling of burning in the chest and can result in the flow of acid into the throat causing acid reflux or regurgitation . If irritation, infection, and/or inflammation to the esophagus continues, it is likely that the symptoms and signs will increase.

If a specific cause for pruritus ani is found it is classified as "secondary pruritus ani". If a specific cause is NOT found it is classified as "idiopathic pruritus ani". The irritation can be caused by intestinal parasites, anal perspiration, frequent liquid stools, diarrhea, residual stool deposits, or the escape of small amounts of stool as a result of incontinence or flatulence. Another cause is yeast infection or candidiasis. Some diseases increase the possibility of yeast infections, such as diabetes mellitus or HIV infection. Treatment with antibiotics can bring about a disturbance of the natural balance of intestinal flora, and lead to perianal thrush, a yeast infection affecting the anus. Psoriasis also can be present in the anal area and cause irritation. Abnormal passageways (fistulas) from the small intestine or colon to the skin surrounding the anus can form as a result of disease (such as Crohn's disease), acting as channels which may allow leakage of irritating fluids to the anal area. Other problems that can contribute to anal itching include pinworms, hemorrhoids, tears of the anal skin near the mucocutaneous junction (fissures), and skin tags (abnormal local growth of anal skin). Aside from diseases relative to the condition, a common view suggests that the initial cause of the itch may have passed, and that the illness is in fact prolonged by what is known as an itch-scratch-itch cycle. It states that scratching the itch encourages the release of inflammatory chemicals, which worsen redness, intensifies itchiness and increases the area covered by dry skin, thereby causing a snowball effect.

Some authorities describe “psychogenic pruritus” or "functional itch disorder", where psychological factors may contribute to awareness of itching.

Ingestion of helminth (worm) "Enterobius vermicularis" (pinworm, or threadworm) eggs leads to enterobiasis, indicative of severe itching around the anus from migration of gravid females from the bowel. Severe cases of enterobiasis result in hemorrhage and eczema.

Causes can be:

- Mallory-Weiss syndrome: bleeding tears in the esophagal mucosa, usually caused by prolonged and vigorous retching.

- Irritation or erosion of the lining of the esophagus or stomach

- Vomiting of ingested blood after hemorrhage in the oral cavity, nose or throat

- Vascular malfunctions of the gastrointestinal tract, such as bleeding gastric varices or intestinal varices

- Tumors of the stomach or esophagus.

- Radiation poisoning

- Viral hemorrhagic fevers

- Gastroenteritis

- Gastritis

- Peptic ulcer

- Chronic viral hepatitis

- Intestinal schistosomiasis (caused by the parasite "Schistosoma mansoni")

- History of smoking

- Iatrogenic injury (invasive procedure such as endoscopy or transesophageal echocardiography)

- Zollinger–Ellison syndrome (severe peptic ulcer)

- Atrio-oesophageal fistula

- Yellow fever

Pruritus ani is the irritation of the skin at the exit of the rectum, known as the anus, causing the desire to scratch. The intensity of anal itching increases from moisture, pressure, and rubbing caused by clothing and sitting. At worst, anal itching causes intolerable discomfort that often is accompanied by burning and soreness. It is estimated that up to 5% of the population of the United States experiences this type of discomfort daily.

In adults, most common causes are hemorrhoids and diverticulosis, both of which are relatively benign; however, it can also be caused by colorectal cancer, which is potentially fatal. In a newborn infant, haematochezia may be the result of swallowed maternal blood at the time of delivery, but can also be an initial symptom of necrotizing enterocolitis, a serious condition affecting premature infants. In babies, haematochezia in conjunction with abdominal pain is associated with intussusception. In adolescents and young adults, inflammatory bowel disease, particularly ulcerative colitis, is a serious cause of haematochezia that must be considered and excluded.

Hematochezia can be due to upper gastrointestinal bleeding. However, as the blood from such a bleed is usually chemically modified by action of acid and enzymes, it presents more commonly as black "tarry" feces known as melena. Haematochezia from an upper gastrointestinal source is an ominous sign, as it suggests a very significant bleed which is more likely to be life-threatening.

Beeturia can cause red colored feces after eating beets because of insufficient metabolism of a red pigment, and is a differential sign that may be mistaken as hematochezia.

Consumption of dragon fruit or pitaya may also cause red discoloration of the stool and sometimes the urine (pseudohematuria). This too, is a differential sign that is sometimes mistaken for hematochezia.

In infants, the Apt test can be used to distinguish fetal hemoglobin from maternal blood.

Other common causes of blood in the stool include:

- Colorectal cancer

- Crohns disease

- Ulcerative colitis

- Other types of inflammatory bowel disease, inflammatory bowel syndrome, or ulceration

- Rectal or anal hemorrhoids or anal fissures, particularly if they rupture or are otherwise irritated

- "Shigella" or shiga toxin producing "E. coli" food poisoning

- Necrotizing enterocolitis

- Diverticulosis

- Salmonellosis

- Upper gastrointestinal bleeding

- Peptic ulcer disease

- Esophageal varices

- Gastric cancer

- Intense exercise, especially a high-impact activity like running in hot weather.

Malnutrition (improper dietary intake) or malabsorption (poor absorption of nutrients into the body) can lead to nutritional deficiency states, several of which can lead to stomatitis. For example, deficiencies of iron, vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B6 (pyridoxine), vitamin B9 (folic acid) or vitamin B12 (cobalamine) may all manifest as stomatitis. Iron is necessary for the upregulation of transcriptional elements for cell replication and repair. Lack of iron can cause genetic downregulation of these elements, leading to ineffective repair and regeneration of epithelial cells, especially in the mouth and lips. Many disorders which cause malabsorption can cause deficiencies, which in turn causes stomatitis. Examples include tropical sprue.

When the environment is dry especially in winter, it can create a sensation of dryness and a scratchy feeling in the throat. This is most commonly observed in the morning. Other individuals who also develop throat irritation are those breathing through their mouth because of a congested nose.

Environmental pollution is also a common cause of throat irritation. In fact, indoor pollution because of tobacco smoke used to be a common cause of throat irritation. Other items known to induce throat irritation include alcohol, spicy or hot foods and smokeless tobacco.

Aphthous stomatitis (canker sores) is the recurrent appearance of mouth ulcers in otherwise healthy individuals. The cause is not completely understood, but it is thought that the condition represents a T cell mediated immune response which is triggered by a variety of factors. The individual ulcers (aphthae) recur periodically and heal completely, although in the more severe forms new ulcers may appear in other parts of the mouth before the old ones have finished healing. Aphthous stomatitis is one of the most common diseases of the oral mucosa, and is thought to affect about 20% of the general population to some degree. The symptoms range from a minor nuisance to being disabling in their impact on eating, swallowing and talking, and the severe forms can cause people to lose weight. There is no cure for aphthous stomatitis, and therapies are aimed at alleviating the pain, reducing the inflammation and promoting healing of the ulcers, but there is little evidence of efficacy for any treatment that has been used.

Conditions such as ulcerative colitis or certain types of relapsing infectious diarrhea can vary in severity over time, and FOBT may assist in assessing the severity of the disease. Medications associated with gastrointestinal bleeding such as Bortezomib are sometimes monitored by FOBT.

Safety regulations from US accreditor the Joint Commission may have unintentionally decreased digital rectal examination and FOBT in hospital settings such as Emergency Departments.

This affliction is a common cause of throat irritation. Normally the stomach produces acid in the stomach which is neutralized in the small intestine. To prevent acid from flowing backwards, the lower part of the swallowing tube (esophagus) has a valve which closes after food passes through. In some individuals, this valve becomes incompetent and acid goes up into the esophagus. Reflux episodes often occur at night and one may develop a bitter taste in the mouth. The throat can be severely irritated when acid touches the vocal cords and can lead to spasms of coughing. To prevent throat irritation from reflux, one should lose weight, stop smoking, avoid coffee beverages and sleep with the head elevated.

There is considerable research into the causes, diagnosis and treatments for FGIDs. Diet, microbiome, genetics, neuromuscular function and immunological response all interact. Heightened mast cell activation has been proposed to be a common factor among FGIDs, contributing to visceral hypersensitivity as well as epithelial, neuromuscular, and motility dysfunction.

The interaction between fecal enzyme activity and IDD explains the observation that infant diet and diaper rash are linked because fecal enzymes are in turn affected by diet. Breast-fed babies, for example, have a lower incidence of diaper rash, possibly because their stools have higher pH and lower enzymatic activity. Diaper rash is also most likely to be diagnosed in infants 8–12 months old, perhaps in response to an increase in eating solid foods and dietary changes around that age that affect fecal composition. Any time an infant’s diet undergoes a significant change (i.e. from breast milk to formula or from milk to solids) there appears to be an increased likelihood of diaper rash.

The link between feces and IDD is also apparent in the observation that infants are more susceptible to developing diaper rash after treating with antibiotics, which affect the intestinal microflora. Also, there is an increased incidence of diaper rash in infants who have suffered from diarrhea in the previous 48 hours, which may be because fecal enzymes such as lipase and protease are more active in feces which have passed rapidly through the gastrointestinal tract.

Stercoral ulcer is an ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation due to large bowel obstruction. It is most commonly located in the rectum. Individuals with this condition are at risk for stercoral perforation.

Although wetness alone has the effect of macerating the skin, softening the stratum corneum, and greatly increasing susceptibility to friction injury, urine has an additional impact on skin integrity because of its effect on skin pH. While studies show that ammonia alone is only a mild skin irritant, when urea breaks down in the presence of fecal urease it increases pH because ammonia is released, which in turn promotes the activity of fecal enzymes such as protease and lipase. These fecal enzymes increase the skin's hydration and permeability to bile salts which also act as skin irritants.

There is no detectable difference in rates of diaper rash in conventional disposable diaper wearers and reusable cloth diaper wearers. "Babies wearing superabsorbent disposable diapers with a central gelling material have fewer episodes of diaper dermatitis compared with their counterparts wearing cloth diapers. However, keep in mind that superabsorbent diapers contain dyes that were suspected to cause allergic contact dermatitis (ACD)." Whether wearing cloth or disposable diapers they should be changed frequently to prevent diaper rash, even if they don't feel wet. To reduce the incidence of diaper rash, disposable diapers have been engineered to pull moisture away from the baby's skin using synthetic non-biodegradable gel. Today, cloth diapers use newly available superabsorbent microfiber cloth placed in a pocket with a layer of light permeable material that contacts the skin. This design serves to pull moisture away from the skin in to the microfiber cloth. This technology is used in most major pocket cloth diapers brands today.

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.

Hematochezia is the passage of fresh blood through the anus, usually in or with stools (contrast with melena). Hematochezia is commonly associated with lower gastrointestinal bleeding, but may also occur from a brisk upper gastrointestinal bleed. The difference between hematochezia and rectorrhagia is that, in the latter, rectal bleeding is not associated with defecation; instead, it is associated with expulsion of fresh bright red blood without stools. The phrase bright red blood per rectum (BRBPR) is associated with hematochezia and rectorrhagia. It is also important to differentiate from hematopapyrus - blood on the toilet paper noticed when wiping. The term is from Greek αἷμα ("blood") and χέζειν ("to defaecate").

The wounds from which ulcers arise can be caused by a wide variety of factors, but the main cause is impaired blood circulation. Especially, chronic wounds and ulcers are caused by poor circulation, either through cardiovascular issues or external pressure from a bed or a wheelchair. A very common and dangerous type of skin ulcers are caused by what are called pressure-sensitive sores, more commonly called bed sores and which are frequent in people who are bedridden or who use wheelchairs for long periods. Other causes producing skin ulcers include bacterial or viral infections, fungal infections and cancers. Blood disorders and chronic wounds can result in skin ulcers as well.

Venous leg ulcers due to impaired circulation or a blood flow disorder are more common in the elderly.

Hematemesis or haematemesis is the vomiting of blood. The source is generally the upper gastrointestinal tract, typically above the suspensory muscle of duodenum. Patients can easily confuse it with hemoptysis (coughing up blood), although the latter is more common. Hematemesis "is always an important sign".

The risk of chemotherapy-induced nausea and vomiting varies based on the type of treatment received, as well as several outside factors. Some types of chemotherapy are more prone to causing nausea and vomiting than others. Some chemotheraputic agents may not cause nausea and vomiting on their own, but may when used in combination with other agents. Regimens that are linked to a high incidence (90% or higher) of nausea and vomiting are referred to as "highly emetogenic chemotherapy", and those causing a moderate incidence (30–90%) of nausea and vomiting are referred to as "moderately emetogenic chemotherapy".

Some highly emetogenic agents and chemotherapy regimens include:

- Cisplatin

- Dacarbazine

- Cyclophosphamide (>1500 mg/m)

- Carmustine (>250 mg/m)

- Mechlorethamine

- Streptozocin

- ABVD

- MOPP/COPP/BEACOPP

- CBV

- VIP

- BEP

- AC

Some moderately emetogenic agents and regimens include:

- Carboplatin

- Methotrexate

- Doxorubicin/Adriamycin

- Docetaxel

- Paclitaxel

- Etoposide

- Ifosfamide

- Cyclophosphamide (≤1500 mg/m)

- CHOP/CHOP-R

Besides the type of treatment, personal factors may put a patient at greater risk for CINV. Other risk factors include:

- Female sex

- Patient age (under 55 years old)

- History of light alcohol use

- History of previous CINV

- History of nausea and vomiting during pregnancy

- History of motion sickness

- Anxiety or depression

- Anticipation of CINV

Many conditions can cause glossitis via malnutrition or malabsorption, which creates the nutritional deficiencies described above, although other mechanisms may be involved in some of those conditions listed.

- Alcoholism

- Sprue (celiac disease, or tropical sprue), secondary to nutritional deficiencies

- Crohn’s disease

- Whipple disease

- Glucagonoma syndrome

- Cowden disease

- Acquired immunodeficiency syndrome (AIDS)

- Carcinoid syndrome

- Kwashiorkor amyloidosis

- Veganism and other specialized diets,

- Poor hydration and low saliva in the mouth, which allows bacteria to grow more readily

- Mechanical irritation or injury from burns, rough edges of teeth or dental appliances, or other trauma

- Tongue piercing Glossitis can be caused by the constant irritation by the ornament and by colonization of Candida albicans in site and on the ornament

- Exposure to irritants such as tobacco, alcohol, hot foods, or spices

- Allergic reaction to toothpaste, mouthwash, breath fresheners, dyes in confectionery, plastic in dentures or retainers, or certain blood-pressure medications (ACE inhibitors)

- Administration of ganglion blockers (e.g., Tubocurarine, Mecamylamine).

- Oral lichen planus, erythema multiforme, aphthous ulcer, pemphigus vulgaris

- Heredity

- Albuterol (bronchodilator medicine)

- Schizophrenia

A painful tongue may be an indication of an underlying serious medical condition and nearly always merits assessment by a physician or dental surgeon.

Gastrointestinal perforation, also known as ruptured bowel, is a hole in the wall of part of the gastrointestinal tract. The gastrointestinal tract includes the esophagus, stomach, small intestine, and large intestine. Symptoms include severe abdominal pain and tenderness. When the hole is in the stomach or early part of the small intestine the onset of pain is typically sudden while with a hole in the large intestine onset may be more gradual. The pain is usually constant in nature. Sepsis, with an increased heart rate, increased breathing rate, fever, and confusion may occur.

The cause can include trauma such as from a knife wound, eating a sharp object, or a medical procedure such as colonoscopy, bowel obstruction such as from a volvulus, colon cancer, or diverticulitis, stomach ulcers, ischemic bowel, and a number of infections including "C. difficile". A hole allows intestinal contents to enter the abdominal cavity. The entry of bacteria results in a condition known as peritonitis or in the formation of an abscess. A hole in the stomach can also lead to a chemical peritonitis due to gastric acid. A CT scan is typically the preferred method of diagnosis; however, free air from a perforation can often be seen on plain X-ray.

Perforation anywhere along the gastrointestinal tract typically requires emergency surgery in the form of an exploratory laparotomy. This is usually carried out along with intravenous fluids and antibiotics. A number of different antibiotics may be used such as piperacillin/tazobactam or the combination of ciprofloxacin and metronidazole. Occasionally the hole can be sewn closed while other times a bowel resection is required. Even with maximum treatment the risk of death can be as high as 50%. A hole from a stomach ulcer occurs in about 1 per 10,000 people per year, while one from diverticulitis occurs in about 0.4 per 10,000 people per year.