Amnesia is a general term that describes memory loss. The loss can be temporary or permanent, but 'amnesia' usually refers to the temporary variety. Causes include head and brain injuries, certain drugs, alcohol, traumatic events, or conditions such as Alzheimer's disease. Anterograde amnesia means that the person can't learn anything new, while retrograde amnesia means the person forgets events from their past. In many mild cases, such as those caused by concussion, the person can't recall the blow to the head or their recovery time, but the rest of their memory is intact. Infantile amnesia, or the inability to remember anything at all from the first few months or years of life, is universal. It is thought that the memory processes of the brain take time to develop.
Symptoms
The symptoms of amnesia depend on the cause, but generally include:
* Memory loss
* Confusion
* Inability to recognise familiar faces or places
* Once the person recovers, they typically have no memory of their amnesia episode.
A range of causes
Memory loss can be caused by a wide range of conditions, including:
* Head injury
* Severe illness
* High fever
* Seizures
* Emotional shock or hysteria
* Alcohol-related brain damage
* Certain drugs, such as barbiturates or heroin
* General anaesthetics
* Electroconvulsive therapy
* Stroke
* Transient ischaemic attack (a 'mini stroke')
* Alzheimer's disease
* Brain surgery.
Memory is mysterious
The way the brain codes and stores information remains a mystery. Current and often conflicting theories include:
* Widespread distribution of memories across the outermost layer of the brain (cortex)
* Widespread distribution of memories, with certain structures (such as the hippocampus) playing important roles
* Localised memory areas in certain structures of the brain only
* Memory storage in brain molecules
* Memory storage in clusters of nerve cells (neurones).
Different types of memory
It seems that the brain has a number of different memory forms, including:
* Short term - new information is stored for a brief time. If the information isn't further processed, it will soon be forgotten.
* Long term - information from the short term memory is shifted to the long term memory.
* Declarative - conscious memories of information and events.
* Non-declarative - once learned, habits such as driving a car are ingrained and automatic.
The severity varies
The severity of amnesia depends on the cause. Concussion, seizures and electroconvulsive therapy seem to temporarily disrupt the electrical activity of the brain and prevent the short term memory from working properly. The stress of a traumatic event may also interfere with the processing of short term memories. These episodes of amnesia are usually temporary. In more severe cases, memory loss may be permanent. Brain trauma or some types of brain surgery, may damage vital memory structures. The type of memory loss experienced depends on which parts of the brain are affected. In Alzheimer's disease, the person typically remembers past events, but experiences memory losses dating from the onset of their condition.
Diagnosis methods
Diagnosing the cause of amnesia involves a range of tests, including:
* Medical history
* General examination
* Tests for short and long term memory recall
* Other tests related to thought processing
* Head x-ray
* Blood tests
* Computerised tomography (CT) scan
* Cerebral angiography (scans taken after a special dye is injected).
Treatment options
Treatment depends on the cause. For example, a person who has suffered a traumatic event may benefit from sedation, plenty of love and care, and (perhaps) psychiatric treatment. Concussion needs rest, once complications have been ruled out. If alcoholism is the cause, then abstinence, emotional support and addressing dietary deficiencies are recommended. In the case of Alzheimer's disease, a range of new medications that enhance the cholinergic function of the brain are now available; however, nursing homes or other extended care options may eventually be needed as the person becomes less able to look after themselves.
Source: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Amnesia?open
Jumat, 02 Mei 2008
Kamis, 24 April 2008
About Cancer
Cancer (medical term: malignant neoplasm) is a class of diseases in which a group of cells display the traits of uncontrolled growth (growth and division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, do not invade or metastasize. Most cancers form a tumor but some, like leukemia, do not.
Cancer may affect people at all ages, even fetuses, but risk for the more common varieties tends to increase with age.[1] Cancer causes about 13% of all deaths.[2] According to the American Cancer Society, 7.6 million people died from cancer in the world during 2007.[3] Apart from humans, forms of cancer may affect other animals and plants.
Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. Complex interactions between carcinogens and the host genome may explain why only some develop cancer after exposure to a known carcinogen. New aspects of the genetics of cancer pathogenesis, such as DNA methylation, and microRNAs are increasingly being recognized as important.
Genetic abnormalities found in cancer typically affect two general classes of genes. Cancer-promoting oncogenes are often activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments. Tumor suppressor genes are often inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues, and interaction with protective cells of the immune system.
Cancer is usually classified according to the tissue from which the cancerous cells originate, the primary tumor, as well as the normal cell type they most resemble. These are location and histology, respectively. A definitive diagnosis usually requires the histologic examination of a tissue biopsy specimen by a pathologist, although the initial indication of malignancy can be symptoms or radiographic imaging abnormalities. Most cancers can be treated and some cured, depending on the specific type, location, and stage. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for different varieties of cancer. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of cancer patients is most influenced by the type of cancer, as well as the stage, or extent of the disease. In addition, histologic grading and the presence of specific molecular markers can also be useful in establishing prognosis, as well as in determining individual treatments.
--Pneumonectomy specimen containing a lung cancer, here a Squamous cell carcinoma (the whitish tumor near the bronchi)--
--Mastectomy specimen containing a very large cancer of the breast (in this case, an invasive ductal carcinoma)--
--Colectomy specimen containing an invasive colorectal carcinoma (the crater-like, reddish, irregularly-shaped tumor)--
--When normal cells are damaged beyond repair, they are eliminated by apoptosis (A). Cancer cells avoid apoptosis and continue to multiply in an unregulated manner (B).
DiseasesDB 28843
MedlinePlus 001289
MeSH D009369--
Cancer may affect people at all ages, even fetuses, but risk for the more common varieties tends to increase with age.[1] Cancer causes about 13% of all deaths.[2] According to the American Cancer Society, 7.6 million people died from cancer in the world during 2007.[3] Apart from humans, forms of cancer may affect other animals and plants.
Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. Complex interactions between carcinogens and the host genome may explain why only some develop cancer after exposure to a known carcinogen. New aspects of the genetics of cancer pathogenesis, such as DNA methylation, and microRNAs are increasingly being recognized as important.
Genetic abnormalities found in cancer typically affect two general classes of genes. Cancer-promoting oncogenes are often activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments. Tumor suppressor genes are often inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues, and interaction with protective cells of the immune system.
Cancer is usually classified according to the tissue from which the cancerous cells originate, the primary tumor, as well as the normal cell type they most resemble. These are location and histology, respectively. A definitive diagnosis usually requires the histologic examination of a tissue biopsy specimen by a pathologist, although the initial indication of malignancy can be symptoms or radiographic imaging abnormalities. Most cancers can be treated and some cured, depending on the specific type, location, and stage. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for different varieties of cancer. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of cancer patients is most influenced by the type of cancer, as well as the stage, or extent of the disease. In addition, histologic grading and the presence of specific molecular markers can also be useful in establishing prognosis, as well as in determining individual treatments.
--Nephrectomy specimen containing a Renal cell carcinoma (the yellowish, spongy-looking tumor in the lower left)--
--Pneumonectomy specimen containing a lung cancer, here a Squamous cell carcinoma (the whitish tumor near the bronchi)--
--Mastectomy specimen containing a very large cancer of the breast (in this case, an invasive ductal carcinoma)--
--Colectomy specimen containing an invasive colorectal carcinoma (the crater-like, reddish, irregularly-shaped tumor)--
--When normal cells are damaged beyond repair, they are eliminated by apoptosis (A). Cancer cells avoid apoptosis and continue to multiply in an unregulated manner (B).
DiseasesDB 28843
MedlinePlus 001289
MeSH D009369--
Senin, 21 April 2008
About Autism
Autism is a brain development disorder that impairs social interaction and communication, and causes restricted and repetitive behavior, all starting before a child is three years old. This set of signs distinguishes autism from milder autism spectrum disorders (ASD) such as Asperger syndrome.
Autism has a strong genetic basis, although the genetics of autism are complex and it is unclear whether ASD is explained more by multigene interactions or by rare mutations. In rare cases, autism is strongly associated with agents that cause birth defects. Other proposed causes, such as childhood vaccines, are controversial and the vaccine hypotheses lack convincing scientific evidence. Most recent reviews estimate a prevalence of one to two cases per 1,000 people for autism, and about six per 1,000 for ASD, with ASD averaging a 4.3:1 male-to-female ratio. The number of people known to have autism has increased dramatically since the 1980s, at least partly due to changes in diagnostic practice; the question of whether actual prevalence has increased is unresolved.
Autism affects many parts of the brain; how this occurs is poorly understood. Parents usually notice signs in the first two years of their child's life. Early behavioral or cognitive intervention can help children gain self-care, social, and communication skills. There is no cure. Few children with autism live independently after reaching adulthood, but some become successful, and an autistic culture has developed, with some seeking a cure and others believing that autism is a condition rather than a disorder.
Repetitive behavior
A young boy with autism, and the precise line of toys he made
Autistic individuals display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R) categorizes as follows.
* Stereotypy is apparently purposeless movement, such as hand flapping, head rolling, or body rocking.
* Compulsive behavior is intended and appears to follow rules, such as arranging objects in a certain way.
* Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
* Ritualistic behavior involves the performance of daily activities the same way each time, such as an unvarying menu or dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.
* Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program.
* Self-injury includes movements that injure or can injure the person, such as biting oneself. Dominick et al. reported that self-injury at some point affected about 30% of children with ASD.
No single repetitive behavior seems to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors.
Source: http://en.wikipedia.org/wiki/Autism
Autism has a strong genetic basis, although the genetics of autism are complex and it is unclear whether ASD is explained more by multigene interactions or by rare mutations. In rare cases, autism is strongly associated with agents that cause birth defects. Other proposed causes, such as childhood vaccines, are controversial and the vaccine hypotheses lack convincing scientific evidence. Most recent reviews estimate a prevalence of one to two cases per 1,000 people for autism, and about six per 1,000 for ASD, with ASD averaging a 4.3:1 male-to-female ratio. The number of people known to have autism has increased dramatically since the 1980s, at least partly due to changes in diagnostic practice; the question of whether actual prevalence has increased is unresolved.
Autism affects many parts of the brain; how this occurs is poorly understood. Parents usually notice signs in the first two years of their child's life. Early behavioral or cognitive intervention can help children gain self-care, social, and communication skills. There is no cure. Few children with autism live independently after reaching adulthood, but some become successful, and an autistic culture has developed, with some seeking a cure and others believing that autism is a condition rather than a disorder.
Repetitive behavior
A young boy with autism, and the precise line of toys he made
Autistic individuals display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R) categorizes as follows.
* Stereotypy is apparently purposeless movement, such as hand flapping, head rolling, or body rocking.
* Compulsive behavior is intended and appears to follow rules, such as arranging objects in a certain way.
* Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
* Ritualistic behavior involves the performance of daily activities the same way each time, such as an unvarying menu or dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.
* Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program.
* Self-injury includes movements that injure or can injure the person, such as biting oneself. Dominick et al. reported that self-injury at some point affected about 30% of children with ASD.
No single repetitive behavior seems to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors.
Source: http://en.wikipedia.org/wiki/Autism
About Asthma
Asthma is a chronic condition (generally associated with humans but also controversially being diagnosed in housepets such as cats) involving the respiratory system in which the airway occasionally constricts, becomes inflamed, and is lined with excessive amounts of mucus, often in response to one or more triggers. These episodes may be triggered by such things as exposure to an environmental stimulant (or allergen) such as cold air, warm air, perfume, moist air, exercise or exertion, or emotional stress. In children, the most common triggers are viral illnesses such as those that cause the common cold. This airway narrowing causes symptoms such as wheezing, shortness of breath, chest tightness, and coughing. The airway constriction responds to bronchodilators. Between episodes, most patients feel well but can have mild symptoms and they may remain short of breath after exercise for longer periods of time than the unaffected individual. The symptoms of asthma, which can range from mild to life threatening, can usually be controlled with a combination of drugs and environmental changes.
Public attention in the developed world has recently focused on asthma because of its rapidly increasing prevalence, affecting up to one in four urban children.
Signs and symptoms
An acute exacerbation of asthma is commonly referred to as an asthma attack. The clinical hallmarks of an attack are shortness of breath (dyspnea) and either wheezing or stridor. Although the former is "often regarded as the sine qua non of asthma", some patients present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing may be heard. When present the cough may sometimes produce clear sputum. The onset may be sudden, with a sense of constriction in the chest, breathing becomes difficult, and wheezing occurs (primarily upon expiration, but can be in both respiratory phases).
Signs of an asthmatic episode include wheezing, prolonged expiration, a rapid heart rate (tachycardia), rhonchous lung sounds (audible through a stethoscope), the presence of a paradoxical pulse (a pulse that is weaker during inhalation and stronger during exhalation), and over-inflation of the chest. During a serious asthma attack, the accessory muscles of respiration (sternocleidomastoid and scalene muscles of the neck) may be used, shown as in-drawing of tissues between the ribs and above the sternum and clavicles.
During very severe attacks, an asthma sufferer can turn blue from lack of oxygen, and can experience chest pain or even loss of consciousness. Just before loss of consciousness, there is a chance that the patient will feel numbness in the limbs and palms may start to sweat. The person's feet may become icy cold. Severe asthma attacks, which may not be responsive to standard treatments (status asthmaticus), are life-threatening and may lead to respiratory arrest and death. Despite the severity of symptoms during an asthmatic episode, between attacks an asthmatic may show few or even no signs of the disease.
In some individuals asthma is characterized by chronic respiratory impairment. In others it is an intermittent illness marked by episodic symptoms that may result from a number of triggering events, including upper respiratory infection, stress, airborne allergens, air pollutants (such as smoke or traffic fumes), or exercise. Some or all of the following symptoms may be present in those with asthma: dyspnea, wheezing, stridor, coughing, an inability for physical exertion. Some asthmatics who have severe shortness of breath and tightening of the lungs never wheeze or have stridor and their symptoms may be confused with a COPD-type disease.
An acute exacerbation of asthma is commonly referred to as an asthma attack. The clinical hallmarks of an attack are shortness of breath (dyspnea) and either wheezing or stridor. Although the former is "often regarded as the sine qua non of asthma", some patients present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing may be heard. When present the cough may sometimes produce clear sputum. The onset may be sudden, with a sense of constriction in the chest, breathing becomes difficult, and wheezing occurs (primarily upon expiration, but can be in both respiratory phases).
Signs of an asthmatic episode include wheezing, prolonged expiration, a rapid heart rate (tachycardia), rhonchous lung sounds (audible through a stethoscope), the presence of a paradoxical pulse (a pulse that is weaker during inhalation and stronger during exhalation), and over-inflation of the chest. During a serious asthma attack, the accessory muscles of respiration (sternocleidomastoid and scalene muscles of the neck) may be used, shown as in-drawing of tissues between the ribs and above the sternum and clavicles.
During very severe attacks, an asthma sufferer can turn blue from lack of oxygen, and can experience chest pain or even loss of consciousness. Just before loss of consciousness, there is a chance that the patient will feel numbness in the limbs and palms may start to sweat. The person's feet may become icy cold. Severe asthma attacks, which may not be responsive to standard treatments (status asthmaticus), are life-threatening and may lead to respiratory arrest and death. Despite the severity of symptoms during an asthmatic episode, between attacks an asthmatic may show few or even no signs of the disease.
An acute exacerbation of asthma is commonly referred to as an asthma attack. The clinical hallmarks of an attack are shortness of breath (dyspnea) and either wheezing or stridor. Although the former is "often regarded as the sine qua non of asthma", some patients present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing may be heard. When present the cough may sometimes produce clear sputum. The onset may be sudden, with a sense of constriction in the chest, breathing becomes difficult, and wheezing occurs (primarily upon expiration, but can be in both respiratory phases).
Signs of an asthmatic episode include wheezing, prolonged expiration, a rapid heart rate (tachycardia), rhonchous lung sounds (audible through a stethoscope), the presence of a paradoxical pulse (a pulse that is weaker during inhalation and stronger during exhalation), and over-inflation of the chest. During a serious asthma attack, the accessory muscles of respiration (sternocleidomastoid and scalene muscles of the neck) may be used, shown as in-drawing of tissues between the ribs and above the sternum and clavicles.
During very severe attacks, an asthma sufferer can turn blue from lack of oxygen, and can experience chest pain or even loss of consciousness. Just before loss of consciousness, there is a chance that the patient will feel numbness in the limbs and palms may start to sweat. The person's feet may become icy cold. Severe asthma attacks, which may not be responsive to standard treatments (status asthmaticus), are life-threatening and may lead to respiratory arrest and death. Despite the severity of symptoms during an asthmatic episode, between attacks an asthmatic may show few or even no signs of the disease.
Source: http://en.wikipedia.org/wiki/Asthma
About Allergies
Allergy is a disorder of the immune system often also referred to as atopy. Allergic reactions occur to environmental substances known as allergens; these reactions are acquired, predictable and rapid. Strictly, allergy is one of four forms of hypersensitivity and is called type I (or immediate) hypersensitivity. It is characterized by excessive activation of certain white blood cells called mast cells and basophils by a type of antibody, known as IgE, resulting in an extreme inflammatory response. Common allergic reactions include eczema, hives, hay fever, asthma, food allergies, and reactions to the venom of stinging insects such as wasps and bees.
Mild allergies like hay fever, are highly prevalent in the human population and cause symptoms such as allergic conjunctivitis, itchiness and runny nose. Similarly, conditions such as asthma are common, in which allergy plays a major role. In some people, severe allergies to environmental or dietary allergens, or to medication, occur that may result in life-threatening anaphylactic reactions and potentially death.
A variety of tests now exist to diagnose allergic conditions; these include testing the skin for responses to known allergens or analyzing the blood for the presence and levels of allergen-specific IgE. Treatments for allergies include allergen avoidance, use of antihistamines, steroids or other oral medications, immunotherapy to desensitize the response to allergen, and targeted therapy.
Signs and symptoms
Common symptoms of allergy Affected organ Symptom
Nose --> swelling of the nasal mucosa (allergic rhinitis)
Sinuses --> allergic sinusitis
Eyes --> redness and itching of the conjunctiva (allergic conjunctivitis)
Airways --> Sneezing, coughing, bronchoconstriction, wheezing and dyspnea, sometimes outright attacks of asthma, in severe cases the airway constricts due to swelling known as angioedema
Ears --> feeling of fullness, possibly pain, and impaired hearing due to the lack of eustachian tube drainage.
Skin --> rashes, such as eczema and hives (urticaria)
Gastrointestinal tract --> abdominal pain, bloating, vomiting, Diarrhea
Many allergens are airborne particles, such as dust or pollen. In these cases, symptoms arise in areas in contact with air, such as eyes, nose and lungs. For instance, allergic rhinitis, also known as hay fever, causes irritation of the nose, sneezing, and itching and redness of the eyes. Inhaled allergens can also lead to asthmatic symptoms, caused by narrowing of the airways (bronchoconstriction) and increased production of mucus in the lungs, shortness of breath (dyspnea), coughing and wheezing.
Aside from these ambient allergens, allergic reactions can result from foods, insect stings, and reactions to medications like aspirin, and antibiotics such as penicillin. Symptoms of food allergy include abdominal pain, bloating, vomiting, diarrhoea, itchy skin, and swelling of the skin during hives or angiooedema. Food allergies rarely cause respiratory (asthmatic) reactions, or rhinitis. Insect stings, antibiotics and certain medicines produce a systemic allergic response that is also called anaphylaxis; multiple systems can be affected including the digestive system, the respiratory system, and the circulatory system. Depending of the rate of severity, it can cause cutaneous reactions, bronchoconstriction, edema, hypotension, coma and even death. This type of reaction can be triggered suddenly or the onset can be delayed. The severity of this type of allergic response often requires injections of epinephrine, sometimes through a device known as the Epi-Pen auto-injector. The nature of anaphylaxis is such that the reaction can seemingly be subsiding, but may recur throughout a prolonged period of time.
Substances that come into contact with the skin, such as latex are also common causes of allergic reactions, known as contact dermatitis or eczema. Skin allergies frequently cause rashes, or swelling and inflammation within the skin, in what is known as a "wheal and flare" reaction characteristic of hives and angioedema.
Source: http://en.wikipedia.org/wiki/Allergies
Mild allergies like hay fever, are highly prevalent in the human population and cause symptoms such as allergic conjunctivitis, itchiness and runny nose. Similarly, conditions such as asthma are common, in which allergy plays a major role. In some people, severe allergies to environmental or dietary allergens, or to medication, occur that may result in life-threatening anaphylactic reactions and potentially death.
A variety of tests now exist to diagnose allergic conditions; these include testing the skin for responses to known allergens or analyzing the blood for the presence and levels of allergen-specific IgE. Treatments for allergies include allergen avoidance, use of antihistamines, steroids or other oral medications, immunotherapy to desensitize the response to allergen, and targeted therapy.
Signs and symptoms
Common symptoms of allergy Affected organ Symptom
Nose --> swelling of the nasal mucosa (allergic rhinitis)
Sinuses --> allergic sinusitis
Eyes --> redness and itching of the conjunctiva (allergic conjunctivitis)
Airways --> Sneezing, coughing, bronchoconstriction, wheezing and dyspnea, sometimes outright attacks of asthma, in severe cases the airway constricts due to swelling known as angioedema
Ears --> feeling of fullness, possibly pain, and impaired hearing due to the lack of eustachian tube drainage.
Skin --> rashes, such as eczema and hives (urticaria)
Gastrointestinal tract --> abdominal pain, bloating, vomiting, Diarrhea
Many allergens are airborne particles, such as dust or pollen. In these cases, symptoms arise in areas in contact with air, such as eyes, nose and lungs. For instance, allergic rhinitis, also known as hay fever, causes irritation of the nose, sneezing, and itching and redness of the eyes. Inhaled allergens can also lead to asthmatic symptoms, caused by narrowing of the airways (bronchoconstriction) and increased production of mucus in the lungs, shortness of breath (dyspnea), coughing and wheezing.
Aside from these ambient allergens, allergic reactions can result from foods, insect stings, and reactions to medications like aspirin, and antibiotics such as penicillin. Symptoms of food allergy include abdominal pain, bloating, vomiting, diarrhoea, itchy skin, and swelling of the skin during hives or angiooedema. Food allergies rarely cause respiratory (asthmatic) reactions, or rhinitis. Insect stings, antibiotics and certain medicines produce a systemic allergic response that is also called anaphylaxis; multiple systems can be affected including the digestive system, the respiratory system, and the circulatory system. Depending of the rate of severity, it can cause cutaneous reactions, bronchoconstriction, edema, hypotension, coma and even death. This type of reaction can be triggered suddenly or the onset can be delayed. The severity of this type of allergic response often requires injections of epinephrine, sometimes through a device known as the Epi-Pen auto-injector. The nature of anaphylaxis is such that the reaction can seemingly be subsiding, but may recur throughout a prolonged period of time.
Substances that come into contact with the skin, such as latex are also common causes of allergic reactions, known as contact dermatitis or eczema. Skin allergies frequently cause rashes, or swelling and inflammation within the skin, in what is known as a "wheal and flare" reaction characteristic of hives and angioedema.
Source: http://en.wikipedia.org/wiki/Allergies
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