Hives

Hives or urticaria is red itchy spots that appear on the skin, their bump-like appearance being the reason for the given name. They usually occur when a person develops an allergy to a drug, insect sting or food item. Infections or stress may also lead to the condition due to the release of certain chemicals such as histamine or mast in the body. Histamine is released when the body is in contact with toxins or pollen. This is a common condition that usually occurs in individuals who are more prone to allergies.

Normally hives lasts about one to two days and in this duration it may change rapidly in size and location by the hour. It may appear to have completed receded, only to quickly reappear in another spot. Hives may be accompanied by a deeper swelling known as angioedema and may also appear in mucous membranes, the eyes and lips.

Chronic urticaria lasts about six weeks and in about 80% of the cases cannot be traced to any allergic reaction. Urticaria may cause difficulty in breathing and shock but this occurs only in rare cases and hives hardly leads to life threatening situations. Hives affects 15 to 20% of the population at some time in the course of their lives. Acute hives in children may be caused due to a viral infection.

Stress hives

It is said that having hives may lead to stress, but stress does not lead to hives. However some studies show that emotional stress may cause hives, as do extreme hot or cold weather conditions. Chronic stress and tension may cause hives, so it is important to find ways to relax and take some time off your normal routine. Stress affects the immune system and may indirectly lead to hives especially when it persists for a long period of time. Stress is known to affect the hormonal balance and the body chemistry leading to hives.

Hives usually recedes by itself without any serious implications. In severe conditions, drugs or injections may be prescribed. Only in rare cases where a swelling blocks the airway and prevents the person from breathing properly, would it be described as an emergency.

Angioedema

Angioedema is similar to hives but these raised swellings are deeper than merely on the surface of the skin, but in the deeper layers. Angioedema is an allergic reaction. Some of the causes for angioedema are certain foods like eggs, berries and nuts, animal dander, medicine allergies and pollen. In angioedema, there is rapid swelling just below the surface of the skin; usualy around the eyes and lips. These welts can be painful and may be accompanied by breathing difficulties and abdominal cramps. When they occur in the airways, the situation can be a medical emergency. Typically antihistamines or anti-inflammatory medicines are prescribed.

Heriditary angioedema: Genetically passed

Allergic angioedema: Reaction to an allergen

Drug-induced angioedema: Side effect to a medication

Idiopathic angioedema: Without any known trigger.

CAT scan

Computed Axial Tomography (CAT scan) is a process of using computers to generate three dimensional images from a flat two dimensional X rays pictures through the 'slice' technique. Aided by computer, cross-sectional views are generated and if needed three dimensional images of the internal organs and structures of the body. In CAT scan the body is seen in 'slices' from the skin to the central part of the body. When all the levels (slices) are added together, a three dimensional picture of an organ is obtained. Together the cross sections give a very accurate picture of where the tumor is and how big or small it is. They also show how close the major body organs are to the area that needs to be treated or operated upon. A CAT scan can be used to define both the normal and abnormal structures the body. It also helps as an accurate guide in placement of instruments and treatments for undergoing procedures.

• The head is examined for trauma injuries, such as blood clots or skull fractures.
  
• Spine is studied for any infections and to check the anatomy of intervertebral discs and spinal cord.
  
• Density of the bone in evaluating osteoporosis is also accurately measured by CAT scan.
  
• CAT scans are used in the chest to identify tumors, cysts or infections.
  
• CAT scans of the abdomen are helpful in defining body organ anatomy, including visualizing liver, gall bladder, pancreas, spleen, aorta, kidneys, uterus and ovaries. Also CAT scans help to verify the presence or absence of tumors, infection, abnormal anatomy or changes in the body from trauma.
  
• CAT scans help to guide the radiologist in performing certain procedures such as biopsyand suspected cancers, removal of internal fluids for various tests.

Many of the procedures in CAT scan are minimally invasive. CAT scan is very low risk procedure. The amount of radiation in CAT scan is very minimal. Unlike MRI, CT scans can be done even if the patient has a pace maker or an internal cardioverter defibrillator devices implanted into the chest to help regulate the heart beat. CAT scan may pose a potential risk to the fetus during the first trimester of pregnancy. Sometimes in contrast studies using iodine-based, there may be itching, a rash, hives or a feeling of warmth throughout the body. But these reactions tend to go away quickly. Very rarely does a more serious reaction occur during intravenous contrast studies. This anaphylactic reaction results in severe hives and/or difficulty in breathing.

Benefits of CAT Scan

• Diagnose muscle and bone disorders such as bone tumors and fractures
  
• Pinpoint the location of tumor, infection and blood clot
  
• Guide certain procedures in surgery
  
• Detect and monitor diseases such as cancer or heart disease
  
• Detect internal injuries and internal bleeding.