What are the Most Common Severe Drug-Induced Anaphylaxis?

Image by James Heilman, MD from Wikipedia

Interesting paper came out listing the most common severe drug-induced anaphylaxis. From a database of 333 patients who suffered from anaphylaxis,

• Anaphylactic shock (76.6%)
• Severe systemic reactions (10.5%)
• Acute laryngeal edema (9%)
• Severe bronchospasm (2.1%)
• Fatal in 6 cases (1.8%)

There were 270 cases (81.1%) of ambulatory anaphylaxis. Sixty-three cases (18.9%) occurred during anesthesia.

84 drugs were identified as being responsible for these cases of anaphylaxis.

• Antibiotics (49.6%)
• Muscle relaxants, latex and anesthetics (15%)
• NSAIDS (10.2%)
• Tylenol (3.9%)
• Iodinated or magnetic resonance imaging contrast media (4.2%)
• Allergy shots and vaccines (3.9%)
• Other drugs (13%)

Among antibiotics, amoxicillin (97 cases), other penicillins (four cases), cephalosporins (41 cases), quinolones (15 cases), and pristinamycin (seven cases) were the most common.

Reference:
Severe drug-induced anaphylaxis: analysis of 333 cases recorded by the Allergy Vigilance Network from 2002 to 2010. Allergy. 2013 Jun 6. doi: 10.1111/all.12168. [Epub ahead of print]

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Another Egg-Free Flu Vaccine Approved by FDA

First there was Flucelvax introduced in 2012 and now there is Flublock, both considered egg-free for those concerned with egg allergy in traditional flu vaccines.

Rather than being cultured in eggs, Flucelvax is cultured in mammalian cells and Flublock is grown in caterpillar cells injected by an insect virus containing the flu gene.

Both vaccines are approved for use in people 18 years and older.

Why the concern of egg-allergic patients with the traditional flu vaccine used to defend against both seasonal and pandemic flu virus?

Traditionally, the flu shot vaccine (both H1N1 and seasonal) are grown inside eggs which is where this concern arises. It also doesn't help that the pre-flu shot questionnaire specifically asks about egg allergy. Though egg-based, during vaccine production the egg protein is filtered out such that there should be no egg contaminants in the final vaccine. However, it is theoretically possible that some egg may still be present in the vaccine.

Although there is an infinitesimal possibility of egg contaminants, studies have shown that even patients with life-threatening egg allergy can still safely have the flu vaccine.

In spite of these reassurances, there are still concerns from patients and healthcare professionals which makes the availability of two different egg-free flu vaccines welcome news.

Source:
FDA approves next-generation, bug-based flu vaccine. MSNBC 1/16/13

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Egg Free Flu Vaccine Approved by FDA

Why the concern of egg-allergic patients with the flu vaccine used to defend against both seasonal and pandemic flu virus?

Traditionally, the flu shot vaccine (both H1N1 and seasonal) are grown inside eggs which is where this concern arises. It also doesn't help that the pre-flu shot questionnaire specifically asks about egg allergy. Though egg-based, during vaccine production the egg protein is filtered out such that there should be no egg contaminants in the final vaccine. However, it is theoretically possible that some egg may still be present in the vaccine.

Although there is an infinitesimal possibility of egg contaminants, studies have shown that even patients with life-threatening egg allergy can still safely have the flu vaccine.

In spite of these reassurances, there are still concerns from patients and healthcare professionals.

As such, there is now a new FDA-approved flu vaccine called Flucelvax which is guaranteed to be egg-free. Rather than being cultured in eggs, this vaccine is cultured in mammalian cells.

Downside is that latex-allergic patients are unable to safely receive this vaccine.

Made by Novartis, this vaccine is approved for use in people 18 years and older.

For more info.

Source:
FDA approves first seasonal influenza vaccine manufactured using cell culture technology. FDA 11/20/12

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Is Flu Shot Safe for Patients With Egg Allergy?

It is the season for flu shots... and with that... we invariably get phone calls from patients asking whether it is safe to receive the flu shot if they are egg allergic. Generally speaking, the blunt answer is that it is safe... even if you have a life-threatening egg allergy.

Why the concern? The flu shot vaccine (both H1N1 and seasonal) are grown inside eggs which is where this concern arises. It also doesn't help that the pre-flu shot questionnaire specifically asks about egg allergy. Though egg-based, during vaccine production the egg protein is filtered out such that there should be no egg contaminants in the final vaccine. However, it is theoretically possible that some egg may still be present in the vaccine.

Given the infinitesimal possibility of egg contaminants, is the concern still legitimate?

There has been a recent study by Canadian researchers who followed 367 egg-allergic people, mostly children, who got the flu shot over five years. Almost one-third of these patients had a significant history of anaphylaxis after eating eggs causing serious symptoms like trouble breathing or a drop in blood pressure. However, in this study, NOT ONE of those patients, experienced a serious reaction to the flu vaccine. Only 13 of the 367 had mild "allergy-like" symptoms, like itchy skin or hives, within a day of the shot.

Furthermore, numerous past studies that involved close to 4,000 egg-allergic people who got the flu shot revealed not a single case of a serious allergic reaction.

However, if such studies still do not alleviate anaphylaxis concern if egg-allergic...

You can either get one of the new completely egg-free flu vaccine Flucelvax or Flublock or...

To play it safe, the absolute safest way for a patient with egg allergy to get the flu shot is via a few steps:

1) Get a test dose of the flu vaccine where a small amount (0.025cc typically) of the flu vaccine is administered sub-dermally.
2) Wait 10-20 minutes.
3) If there's no reaction (redness and swelling of the skin), get the shot properly into the muscle.
4) If there's a large wheal reaction, it's probably best not to get the flu shot or see an allergist to get desensitized prior to receiving the injection.
5) If flu shot given, make patient wait 30 minutes to observe for any adverse reaction.

Not all practices may be familiar with these particular steps. If that's the case, request to take the flu vaccine to an allergy office (including ours), and have us administer it. (Please note that we do not provide egg desensitization.)

If you are only IgG allergic and not IgE allergic to egg, no need to worry. Get the flu shot.

For a more in depth discussion, click here to read a document prepared by the American Academy of Allergy Asthma & Immunology.

Reference:
Egg-allergic patients can be safely vaccinated against influenza. Journal of Allergy and Immunology. In Press. Published Online Oct 1, 2012

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There are FOUR Distinct Types of Allergic Reactions

When people think of allergic reactions, they incorrectly believe there is only one kind... the kind that makes a person's nose run or the rash that appears after eating a food one is allergic to.

Sounds simple, but sadly it is WAY more complex than that.

There are actually 4 distinct types of allergic reactions that occur. All images courtesy of University of Georgia unless otherwise specified.

Type 1
This is the classic type of allergic reaction everyone is familiar with. Generally, it is activated by IgE antibodies in the blood in conjunction with mast cells. This is the type of allergy that is typically tested for by skin prick as well as blood testing (RAST or immunoCAP).

The reaction goes something like this: The allergen (stuff you are allergic to; green starfish in image below) binds IgE (stuff measured in allergy blood tests; Y shape in image) found on mast cells (the cell responsible for allergies). When that happens, the mast cell explodes releasing chemicals that cause all the classic symptoms of allergy.

Type 2
This is the allergic reaction that occurs if you get the wrong blood type during a blood transfusion. Rather than IgE, this reaction is mediated by IgG and does not involve mast cells.

The reaction goes something like this: Antibodies (homing beacons; green Y in image) in the blood attach to certain cells (cells that have a red triangle) which than marks them for destruction. Destructive proteins (called complement) and killer soldier cells than "home in" on these tagged cells and destroy them (like laser-guided missiles).

Courtesy of University of Florida

Type 3
This reaction typically occurs in autoimmune diseases like rheumatoid arthritis but can occur with injections.

The reaction is due to clustering of IgG antibodies (Y shape in image below) and the "allergic" substance (green pellets). This clustering can ultimately create a mega-complex (called immune complex) which can than activate destructive proteins (complement as in Type 2) as well as clog up the small arteries causing surrounding tissue death and/or ischemia.

Type 4
This type of reaction is what mediates latex allergy and other forms of contact dermatitis. It also forms the basis for organ rejection after a transplant as well as the PPD reaction that occurs when testing for tuberculosis.

Rather than antibodies, special cells called macrophages actually directly cause the damage. These cells hunt and "eat" the offending protein or cell with the end result being a "reaction".

Summary
To summarize, take a look at this chart:

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How Does Silver Nitrate Cauterize?

Silver nitrate is a chemical compound commonly used by ENT surgeons to stop nosebleeds as well as obliterate granulation tissue (found around tracheostomy stomas as well as intra-orally).

Medical silver nitrate is typically purchased as matchstick applicators and is usually found in combination with potassium nitrate (75% silver nitrate and 25% potassium nitrate).

When this applicator is combined with water (moisture inside the nose or blood):

AgNO3 + HOH  -->  AgOH + HNO3

Nitric acid (HNO3) is produced along with an insoluble precipitate silver hydroxide (AgOH) which produces the characteristic brownish-white discoloration that can stain clothing as well as skin.

Nitric acid also known as aqua fortis and spirit of niter, is a highly corrosive strong mineral acid and is what initiates the biologic "cauterization" action. It is also what causes a patient to feel a burning sensation when applied.

Silver nitrate applicator sticks can be purchased on Amazon.com.

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How to Make Sudafed from Meth

Given the increasing difficulty in obtaining "over-the-counter" sudafed (pseudoephedrine) to the point where it is easier to obtain the illegal drug methylamphetamine, a chemist has written a paper describing how to make sudafed from meth using reagants found in any well-stocked chemistry lab.

For those who have been living in a hole, sudafed is a good nasal decongestant medication often used for nasal congestion and allergies that is now only found behind the pharmacy counter and dispensed in limited quantities with a record kept of who has purchased. Why?

Because one can make methylamphetamine (meth) from it.

Well, with all the chronic drug shortages, it's a good thing we now have a way to make sudafed from meth.

Read the process here.

First reported in Scientific American.

(this blog article is partly in jest... partly not).

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Food Allergy Reaction Video

So the other day, I was watching the movie Hitch starring Will Smith and Eva Mendes during which there is this one scene where Hitch suffers an allergic reaction from a food he ate during a dinner date. Watch video.

It's actually a pretty good depiction of a reaction due to a food allergy.

However, given the throat-clearing suggesting airway swelling which extends to his face, he really should have called 911 as this not uncommonly leads to death if the airway swelling is severe enough to obstruct his breathing. Along with facial and airway swelling, his blood pressure probably dropped and his heart rate increased to point he could have passed out due to insufficient blood flow to the brain. Of course, it was a movie and none of that happened, but don't think for a second that benadryl alone is adequate.

It is a little unusual for an adult to have a previously unknown food allergy with this severe a reaction in someone as old as Hitch, but not impossible.

Treatment was appropriately given with benadrylin the movie, but in reality Hitch additionally should have gone to the ER where epinephrine and steroids also would have been administered followed by several hours of observation.

After recovery, he should ALWAYS carry an epipen with him. He should also probably see an allergist to determine what it was he reacted to so that he can avoid it in the future.

On another note, in the movie, Hitch literally chugs down an entire bottle of liquid benadryl and acts drunk from it. That usually wouldn't have happened... rather, he would have gotten extremely drowsy and fallen asleep fairly quickly. However, in some individuals, it might occur.

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