Allergy refers to a medical condition where the body's immune system is reacting to a foreign substance (antigen) which should be regarded as harmless to the body. There are six major types of allergic reactions. Of these, three are common and will be discussed in the text below:     Search PubMed for Allergic Rhinitis      

An allergic crease or salute formed from constant rubbing  of the nose
(click to enlarge)
 

  
The first type of allergic reaction is a Type I reaction. This reaction is caused when an antigen attaches to an IgE antibody which then stimulates a "Mast Cell" to release histamine along with a number of other chemical mediators of allergy. (Note: This is why drugs which treat this type of allergy are called antihistamines.)

This type of reaction causes sneezing, itching, hives, welts, wheezing (asthma) and a runny nose. Usually, an allergy does not cause the individual to feel sick all over and does not cause a fever. More severe cases can cause nasal obstruction, facial pressure and facial pain. This type of allergy commonly causes nose and sinus symptoms along with asthma. Some food allergies, such as allergy to shell fish, are mediated by IgE. The symptoms include itching, hives, wheezing and rarely death.

  
Shown in the picture to the right is a nose with chronic allergic rhinitis.  The lining of the nose (mucosa) is white and the secretions are sticky.

The second type of allergy is a Type III reaction it is mediated by IgG and occurs many days after exposure to the foreign substance. Some "Food Allergies" are thought to be this type of allergy.

The third type of allergy is a Type IV delayed hypersensitivity reaction. It is mediated by white blood cells (lymphocytes) and occurs 2 to 5 days after exposure and lasts for up to 21 days. There is a skin rash with deep blisters and intense itching. Poison ivy is a common cause of a delayed hypersensitivity reaction.

Today almost all the prescription "Allergy" drugs available to doctors 5 years ago are now over-the-counter and directly available to the patient. There are many brands of medications with many trade names. Most are marketed as Allergy, Cold and or Sinus Medications. 

Pollens often trigger Type I Inhalational Allergy.  These allergy are usually seasonal with tree and grass pollen in the spring and weed pollens in the fall.  To find out your areas current pollen count and five day projection go to http://www.pollen.com    

Allergy Testing - Inhalation Allergy (click here for food allergy)  The two main types of allergy testing are skin testing and blood or laboratory testing, or RAST.  The goal of skin testing is to lower the circulating IgE level and increase the circulating blocking antibody (IgG4) which will prevent IgE’s interaction with the "Mast Cell". 

Both types of tests measure IgE. These tests are not as accurate in evaluating for food allergies.  Food allergy can be a severe IgE reaction, in which case allergy testing may be contraindicated or food allergy can be a IgG reaction in which case you may not be testing for the proper antibody.  Also, foods are digested by the body and there is little knowledge about the end product that the patient is reacting to. 

Skin Testing: There are two types of skin testing, prick and intradermal.  A useful technique is to use prick testing to determine which antigens cause an allergic reaction and then titrate the positive allergens using intradermal testing to obtain an accurate starting level for desensitization.  This titration method is called skin end point titration -- see right hand picture.  If only prick testing is done, the patient usually starts on a lower dosage of antigen and shots are sometimes given multiple times per week to shorten the time it takes to reach maintenance dosage.  The combination of prick and skin end-point titration (intradermal testing) is less expensive, more accurate, and will allow the patient to start at a higher antigen level for desensitization than a RAST blood test.  Thus, one will reach maintenance dosage sooner.  However, skin testing has more discomfort and rarely a patient can develop a serious reaction.  

RAST testing is useful in children, patients that are at risk for developing a severe reaction, such as asthmatics or patients on Beta Blockers.  However, since you start desensitization at a lower dose than skin testing (RAST minus 1) it will take 10 weeks longer to reach a maintenance dose.   Because of the difficulty in treating anaphylaxis, allergy desensitization should be used with caution in patients taking Beta Blockers.

Once the maintenance dose is reached, allergy shots are often given for 3 to 5 years. They can then be stopped.  After being off of the shots for several years, many patients will experience a recurrence of their symptoms. If this happens, allergy testing should be repeated and allergy shots restarted.  Some allergists will keep patients on allergy shots for a longer period of time but administer the shots less and less frequently, until the shots are given only once or twice a month.
 

 
Medical Therapy

There are several types of over-the-counter allergy medications which are available to the patient.
(to be used under the guidance of your doctor)

#1. Antihistamine: These medications relieve symptoms of allergy such as sneezing, itchy-watery eyes and nasal drainage. However, they also dry secretions in the mouth and lungs and can can cause drowsiness. Other side effects are urinary retention, especially in patients with prostate hypertrophy, and worsening of glaucoma, and rarely impotence. Because of their drying effect, antihistamines are not indicated in "Colds" and may cause worsening of asthma. New longer acting antihistamines are available from your doctor which will not cause as much sedation or drying, and also have less complication. Of the over-the-counter antihistamines, Diphenhydramine (Benedryl) is the most likely to cause drowsiness, Chlor-Trimeton (Chlorpheniramine) causes less drowsiness and loratadine (Claritin) the least. If drowsiness occurs, one should not operate motor vehicles when taking antihistamines.

READ MORE:    Effects of fexofenadine, diphenhydramine (Benedryl), and alcohol on driving performance. A randomized, placebo-controlled trial in the Iowa driving simulator

Antihistamines are broken down in the liver. Over time a patient will become resistant to the drug, as the liver increases its ability to metabolize the drug. Rotating antihistamines or different classes may help to prevent this. (Benedryl Allergy & Travist-1 are in the same class and can be rotated with Chlor-Trimeton Allergy.)

#2 Nasalcrom. This medication takes a long time to work and prevents the "Mast Cell" from releasing mediators when stimulated by IgE. This medication takes a long time to work and usually has to be applied four to six times a day for up to 4 weeks before an improvement is noted.

#3 Decongestants.  Decongestant Nose Sprays Should Seldom Be Used To Treat Allergies. Allergies are usually a long term condition and will not be helped by a three day course of a nose spray. Longer periods of use, will cause addiction and worsening of symptoms.  See Cold & Sinus Section.

#4 Pain Medications.  These rarely need to be used.  Most pain attributed to sinus disease is actually caused by other conditions such as neuromuscular headaches.   See Cold & Sinus Section.  

If you have a heart condition, high blood pressure or diabetes, or are taking MAO inhibitors or Anti-Parkinson Medications:   There are only a few over-the-counter medications you can take for an allergy, since almost all medications contain decongestants.    Decongestants may include phenylephrine, or pseudoephedrine.   Pseudoephedrine is a methamphetamine precursor and this had lead to its restricted sale in some regions of the USA.   A third decongestant, phenylpropanolamine has been taken off the market by the FDA.  

Young Children:  FDA states that cold and sinus medications containing one or more of the following ingredients: decongestants, expectorants, antihistamines and antitussives were found not to be effective in children under the age of 6 years and the safety of there use in this age group had not been established.  See Fox News: http://www.foxnews.com/story/0,2933,303616,00.html   The FDA also recommends NOT using cold and sinus medications in children under the age of two:   http://www.fda.gov/cder/drug/advisory/cough_cold.htm 

Listed below are five over-the-counter medications that contain an antihistamine and NOT a decongestant which your doctor may approve for use with a heart condition or high blood pressure:

Benedryl Allergy--Antihistamine ( diphenhydramine HCL )
Chlor-Trimeton--Antihistamine ( chlorpheniramine maleate )
Claritin--Antihistamine (loratadine)
Travist-1--Antihistamine (clemastine fumarate )
Tylenol Severe Allergy--Antihistamine ( diphenhydramine ) and Pain Medication (acetaminophen).
Zyrtec (Cetirizine)

In addition, Nasalcrom nose spray can also be used since it is not a decongestant and is not addictive.  A prescription drug, Singulair (montelukast) can also be used. 

If you have glaucoma or prostate problems over-the-counter antihistamines should not be used.  The have an anticholenergic effect which can worsen these conditions.  One over prescription antihistamine, Allegra, has little or no anticholenergic effect and may be approved by your doctor for use. 

Antihistamines and No Other Medications:

Antihist-1 ( Clemastine Fumarate )
Benedryl Allergy ( Diphenhydramine )
Chlor-Trimeton Allergy ( Chloropheniramine )
Clariton ( loratadine )
Zyrtec ( Cetirizine )

Decongestant and No Other Medications:

Sudafed Nasal Decongestant ( Pseudoephridrine )

Antihistamines and Decongestants:

Actifed Cold and Allergy ( Triprolidine )
Benadryl Allergy Decongestant ( diphenhydramine )
Chlor-Trimeton Allergy Decongestant ( chlorpheniramine )
Drixoral Cold & Allergy  ( dexbrompheniramine )
Sudafed Cold & Allergy ( chlorpheniramine )

Antihistamines, Decongestants and Pain Medication (Acetaminophen):

Actifed Cold and Sinus  ( chlorpheniramine )
Benadryl Allergy Sinus & Headache ( diphenhydramine )
Benadryl Allergy Cold ( diphenhydramine )
Dimetapp Cold & Fever*  ( brompheniramine )
Drixoral Allergy & Sinus ( dexbrompheniramine )
Sinutab Sinus Allergy   ( chloropheniramine )
Theraflu Flu and Cold ( chloropheniramine )
Tylenol Allergy Sinus ( chlorpheniramine )
Tylenol Allergy Sinus Night Time ( diphenhydramine )

Antihistamine & Pain Medication (Acetaminophen):

Tylenol Severe Allergy  ( diphenhydramine ))

Decongestant Antihistamine & Pain Medication (Acetaminophen):

Dristan Cold Multi-Symptom Tablets ( Phenylephrine HCL, Chlorpheniramine Maleate and Acetaminophen )

Antihistamines, Decongestants and Cough Medication*

Triaminic- Nightiime Liquid*  ( chlorpheniramine )
Vicks Pediatric Formula 44M*  ( chlorpheniramine )

Antihistamines, Decongestants, Pain Medication (Acetaminophen) and Cough Medication *

Comtrex Multi-symptom Cold & Cough Relief  (also in elixir)*  ( chlorpheniramine )
Contact Severe Cold & Flu Maximum Strength   ( chlorpheniramine )
Theraflu Flu, Cold & Cough  ( chlorpheniramine )
Tylenol Cold Complete  ( chlorpheniramine )
Triaminic Severe Cold & Fever  ( chlorpheniramine )

*   Denotes Elixir or Liquid Medication
** Note: This drug combination should be used carefully since you will probably not want to take a cough medication if you have an allergy and you will probably not want the drying effect of an antihistamine if you have a "Cold".

Steroidal Nasal Sprays--Non-addicting, little systemic effects as compared to oral steroids, some approved down to age 6 years. Prolonged use can sometimes cause nose bleeding and thinning of the lining of the nose. Patients taking these medications should be checked by a physician every few months.  The picture on the right shows a through and through area of necrotic nasal septum in a patient who had been using nasal steroid sprays for over one year.
Intranasal Steroids in Children with Allergic Rhinitis   Marcia L. Buck, Pharm.D., FCCP  (Note: The viewer must register for netscape)      
Search PubMed for Nasal Steroids

Non-Sedative Antihistamines-- Three medications are in this category of drugs-- Loratadine (Claritin), Fexofenadine (Allegra) and Cetirizine (Zyrtec).  These are now available over-the-counter, with the exception of Fexofenadine.  These medications have less sedative effects, less drying and less complications of urinary retention and impotence. Some doctors are even starting to use some of these drugs in asthmatic patients. Cetirizine has been shown to have a significant bronchodilatory effect (opens the lung passages)  in patients with mild to moderate asthma.^1,4   Fexofenadine is an antihistamine said to have little or no anti-cholinergic effects and should have less problems with drying, urinary retention and impotence.  Fexofenadine has the shortest half-life and is administered to adults in either a 60 mg bid dosage or in a 180 mg qd dosage.  The Medical Letter has indicated that Loratadine may have decrease effectiveness² and it may be more appropriated to give this drug in a 10 mg bid dosage.³

The Second-Generation (Peripherally-Selective) Antihistamines in Children   Marcia L. Buck, Pharm.D., FCCP  (Note: The viewer must register for netscape) 

• Search PubMed for Loratadine

• Search PubMed for Fexofenadine

• Search PubMed for Cetirizine

Antihistamine Nose Spray-- Astelin (Azelastine HCL) -- This medication is effective in the treatment of both allergic View Abstract   View Abstract and vaso-motor (non-allergic) rhinitis View Abstract.   Because the medication is applied topically it has less systemic complications and increased nasal symptom relief.  It has less complications than topical steroid nose sprays.  The major drawback to asteline nasal spray is that many patients complain of a bad taste and it must be used twice a day.     Search PubMed for azelastine

Oral Leukotriene Inhibitors.  Singulair (montelukast) is a once daily medication which has been shown to reduce symptoms of allergic rhinitis View Abstract  View Abstract by inhibiting leukotriene receptors in the airway.  Stimulation of leukotriene receptors has been shown to cause edema, inflammation and smooth muscle constriction.  Singulair is a well tolerated drug with a low incidence of complications.

Oral Steroids--Oral (or injectable) steroids should only be taken to suppress severe symptoms and only for a short period of time. Steroids have many complications including elevation of blood pressure, worsening of diabetes, elevation of cholesterol. Prolonged use may even be a precipitating factor for strokes, heart attacks, and the formation of blood clots. ONLY USE UNDER THE GUIDANCE OF A DOCTOR.

A combination of oral and intranasal steroids has been shown to be an effective treatment for nasal polyps.   View Abstract

Surgery:  This is reserved as a last resort and is usually performed to relieve sinus blockage or increase nasal airway. Removal of nasal polyps (shown being removed in the picture on the left) is a common indication for surgery.  If the patient is allergic to bacteria or fungi in the sinuses, the operation may result in marked improvement. However, the surgery will often only relieve the symptoms associated with the blocked sinus and not improve the underlining allergy. Thus, after surgery the patient may be improved but will still have to take sinus medications or shots   Surgery for "sinus headaches" is debated and results cannot be guaranteed.  Shields has shown that there was no correlation between the severity of pain and the severity of sinus symptoms.  This brings into question whether sinus disease is causing the symptoms at all. One explanation is that most of this pain is caused by tension headaches and migraines.  The patients just assume the pain is from sinus disease because of the mass marketing of sinus medications they see on television.   View Abstract   Ramadan reported that children under the age of six have more surgical revisions and less benefit from sinus surgery.   View Article  Children exposed to second hand smoke from their parents also have less successful surgical outcomes.   View Article

Sinus surgery is often performed with scopes through the nose and is usually done in an outpatient surgery center ("in-and-out surgery"). Because the sinuses are fixed and the operated tissue does not move, post- operative pain is usually minimal. Surgery is not without risks, injury to the eye and lining of the brain can occur.  However, these structures can also be damaged by untreated sinus disease.

FLASH Animated Sinus Anatomy & CT Scan Slices
 of a Patient with Chronic Sinusitis - 776 Megs

References: