Any inflammation of the skin can be called dermatitis, so there are many different types of dermatitis.
It is often very difficult to determine any cause, for although the skin is the most visible of our organs, its diseases are very diverse and often difficult to diagnose.
In most cases simple steroid anti-inflammatory creams will control dermatitis, but it may become persistent and widespread.
For further information see the specific types of dermatitis.
See also ECZEMA; SCALDED SKIN SYNDROME
Diarrhoea is the frequent and excessive discharge of watery fluid from the bowel. Diarrhoea is really a symptom of disease rather than a disease itself.
Absolutely everyone experiences diarrhoea at some time. The ten metres of an adult human gut is very sensitive to irritants, and any irritation of the lower half, particularly the last two metres (the large intestine), will result in diarrhoea.
Diarrhoea may be considered by a patient to be the more frequent passing of motions that are softer than usual, but to be medically significant, the motions must be at least part liquid and be passed more than four times a day.
Diarrhoea can be caused by conditions of the intestine, or diseases outside the gut that alter the body’s chemistry or other functions.
By far the most common cause of diarrhoea is a viral infection of the intestine (viral gastroenteritis). This infection is passed from one person to another by close contact or on the breath, and usually occurs in epidemics, often in springtime. The usual symptoms are six to twelve hours of vomiting followed by one to three days of diarrhoea, and painful gut spasms usually occur.
Food poisoning is due to bacteria, or a toxin produced by bacteria, being present in food. The diagnosis is most strongly suspected when a whole family or group of people is affected simultaneously. The symptoms and the severity of the attack will depend upon the bacteria causing the poisoning, the amount eaten, and the age and general health of the victim. Most attacks of food poisoning occur abruptly, within eight hours (and often one or two hours) of eating the contaminated food, but some types may take up to 24 hours to give symptoms. The patient suddenly starts vomiting, and has explosive diarrhoea associated with intermittent belly pain.
Bacterial gastroenteritis is usually more severe than the viral form, and includes infections by bacteria such as Shigella, Salmonella typhi (causes typhoid) and Yersinia. These are usually responsible for the “Delhi belly” and “Montezuma’s revenge” suffered by travellers to less developed countries. Vibrio cholerae is the bacteria responsible for cholera, the most severe of the bacterial gut infections.
Giardia lamblia is a microscopic animal that can easily enter the body and cause an infection (giardiasis) in the small intestine. It passes from one person to another by poor personal hygiene. The condition is far more common in children than adults, who may have no symptoms.
Other common intestinal causes of diarrhoea in babies include lactose intolerance (a reaction to the sugar in milk), food allergies (eg. eggs, milk, chocolate, peanuts), intussusception (an infolding of the gut on itself), surgery to shorten the intestine (prevents adequate absorption of fluids), and strangely severe constipation may actually present as diarrhoea because liquid faeces from further up the bowel can seep around the outside of a large faecal mass in the rectum that is impossible to pass through the anus.
There are many medications that may have diarrhoea as a side effect. Examples include antibiotics (particularly penicillin). Over use of laxatives will naturally result in diarrhoea.
There are dozens of other rare causes of diarrhoea.
Faeces may be examined to determine the cause, along with blood tests and sometimes colonoscopy and x- rays.
Treatment involves determining and treating the cause if possible. Mild attacks are dealt with by diet and fluids, more serious ones require medication to slow the flow, and severe attacks may need fluids to be replaced by an intravenous drip.
Dehydration is the main complication, and the risk is much greater in children under five years of age.
See also GASTROENTERITIS
Diphtheria is a childhood respiratory infection that is now rare in developed countries.
It is caused by infection of the throat and trachea (the tube leading to the lungs) by the bacterium Corynebacterium diphtheriae that releases a toxin that is responsible for most of the symptoms and complications. It spreads from one person to another in the breath, and the incubation period is two to seven days.
Symptoms include a sore swollen throat, fever, nasal discharge, hoarse voice, overwhelming tiredness, weakness and muscle aches. A thick, grey, sticky discharge forms a membrane across the throat that the patient constantly fights to clear. The diagnosis is confirmed by throat swabs, and heart involvement by an electrocardiograph (ECG).
Rapid, early treatment is critical and involves diphtheria antitoxin injection, antibiotics (kill the bacteria but do not remove the toxin), and medications to control or prevent complications. In severe cases a tracheotomy (cut into the front of the throat) is performed to allow air into the lungs.
Diphtheria can be totally prevented by vaccination. These vaccinations were first introduced in the 1930s. It is normally given in combination with the tetanus vaccine (and sometimes other vaccines) at two, four, six and eighteen months of age, then at four years and every ten years through life.
Severe cases may affect the heart, nose, skin and nerves. Survivors may be affected for life by damage to the heart or lungs.
The death rate varies from 10% to 30%, and most deaths occur within the first day or two. Survivors improve in a few days, but must be kept at rest for at least three weeks to prevent complications, as it will take this time to for all the toxin to be removed from the body.
See also WHOOPING COUGH
The use of a dummy (pacifier) always causes arguments. If a parent prefers a child to suck a dummy to a thumb, or use one as a pacifier, there is no good reason why not, provided the dummy can be kept clean. To coat a dummy with honey or some other sweet substance is forbidden, as it will cause dental problems and almost inevitably will lead to the child developing a propensity for sweet foods, which can cause lifelong problems.
See also THUMB SUCKING