Why Does EpiPen Have to be Injected into the Thigh?

As any severely food allergic patients know, when suffering from a potentially life-threatening anaphylactic reaction, they need to jab an epinephrine needle into the side of their thigh...

But... why the thigh? Why not the arm like most other shots?

Per AAAAI, there have been 3 anatomic sites investigated to determine which location offers the fastest systemic absorption of epinephrine when injected intramuscularly and/or subcutaneously.

• Intramuscular injection in the upper arm (deltoid muscle) just like a flu shot.
• Subcutaneous injection in the upper arm just like an allergy shot.
• Intramuscular injection in the lateral thigh (vastus lateralis muscle).

Of these sites, the intramuscular thigh injection demonstrated the fastest rise in blood epinephrine.

When dealing with a life-threatening anaphylaxis, you need the speed because if the drug is too slow, the person may die before adequate epinephrine levels are achieved... and the thigh muscle provides the speed whereas the other sites do not.

Why might that be?

It's probably because the thigh muscle is large with lots of blood vessels allowing for multiple points of access for the injected epinephrine to enter into the blood circulation.


References:
Epinephrine absorption in children with a history of anaphylaxis. J Allergy Clin Immunology 1998; 101(1):33-37.

Epinephrine absorption in adults: intramuscular versus subcutaneous injection. J Allergy Clin Immunol 2001; 108(5):871-873.

Hypoallergenic Cats and Dogs

CBS news published a story on hypoallergenic pets on their website here.

The story did report that pricey pets that claim to be easy on allergy sufferers are probably more hype than true, but than did go on to list dogs and cats that are purportedly hypoallergenic.

The claim for hypoallergenicity is based on hair/fur/dander length or quantity... mainly the shorter or smaller the amount, the less allergenic. However, there are other reasons why hypoallergenic pets are NOT hypoallergenic. These include a pet's saliva and skin which contain the same protein that trigger allergic reactions.

Also, many dog allergy sufferers also have weed, tree, and grass allergies. If your hypoallergenic dog likes to roll in the grass and weed, they are getting that all over them and bringing it into the house and to you. So even if you are not allergic to the dog, you probably are allergic to what's on the dog.

Read the CBS story here.

Tongue Piercing Infections

It seems that tongue piercing is slowly becoming more popular than ever... and correspondingly, there seems to be even more tongue infections than ever before due to the piercing.

If tongue piercing MUST happen, it is recommended that you avoid studs made of metal which increases the risk of infection, at least according to a recent study in the Journal of Adolescent Health.

The study demonstrated that studs made of steel might promote the development of a bacterial biofilm leading to increased risk of infection whereas those made of polytetrafluoroethylene or polypropylene are inert to such bacterial colonization.

I should also add that metal studs may cause an allergic reaction leading to painful tongue swelling/itching, especially in those with metal allergies. This is similar to the skin reactions that some people experience with cheap metal jewelry.


Reference:
Tongue piercing: the impact of material on microbiological findings. J Adol Health online, 2011

Stress Can INCREASE a Person's Allergies!

Researchers at Ohio State University recently published an article in the June 2009 journal Psychoneuroendocrinology titled "How stress and anxiety can alter immediate and late phase skin test responses in allergic rhinitis."

What they found was that allergic responses to a skin prick increased after a stressful event compared to a non-stressful event. Anxiety also substantially enhanced the effects of stress far into the future as even skin tests performed the day after the stressor reflected the continuing impact of the stressor among the more anxious participants.

Read the NYT article on this here.

Yet another thing to think about in allergic patients...

Read more about the study here.