After eating peanuts recently, my neck became very itchy. Two days later, I woke up with a feeling that my throat was closing. The skin under my chin is still really itchy and hot nearly a week later. I have suffered with hives in the past — could it be that, or have I developed a nut allergy? I am 64.
Karen Goldman, by email.
Your description of the rash on your neck is highly suggestive of an acute allergic reaction to the peanuts, suppressed to some extent by the antihistamines which, you say in your longer letter, you took straight after the reaction started.
There are nine proteins in the peanut plant (or arachis hypogaea, to give it its botanic name) which can cause allergic reactions.
If an allergic response is triggered by one or more of these proteins, the immune system overreacts and produces antibodies called immunoglobulin E (IgE).
There are nine proteins in the peanut plant (or arachis hypogaea, to give it its botanic name) which can cause allergic reactions
The presence of IgE antibodies is the defining feature of an allergy. They provoke immune cells to release histamine, the chemical which causes many of the symptoms of allergy.
Once you have reacted to something, you will always have these IgE antibodies present in your blood.
Risk factors for developing a peanut allergy later in life include a history of eczema, or a family or personal history of any allergies. So the fact you have previously had hives — an itchy, raised rash that can be related to an allergy — suggests you fall into this high-risk category.
If a patient has a mild allergic reaction to something, their GP might initially prescribe an antihistamine. Only if there was a recurrence or if the cause was uncertain would a referral then occur.
One option then is for a skin test, in which a tiny dot of peanut extract is placed on the skin of the forearm, which is then pricked with a fine needle. A positive reaction — a raised bump surrounded by redness, along with localised itching — calls for a blood test to check for peanut-specific IgE antibodies.
If this comes back positive, it is then recommended that the individual always carries an adrenaline autoinjector (such as an EpiPen) in case of a more severe reaction — such as swelling around the throat and difficulty breathing.
A negative blood test does not necessarily rule out the possibility of an allergy, as there can be both false negative or false positive results.
Your persisting symptoms call for the opinion of an allergy expert.
The fact that your itching and other symptoms began after you started eating peanuts suggests there is a connection. It would be wise to ask your GP for referral to an allergy clinic for further investigations.
In the interim, ask your GP to prescribe an adrenaline autoinjector. Always make sure you have this with you, and take care to avoid any possibility of eating peanuts.
Source: Daily Mail | Top Health News
