Wednesday, 20 February 2013

Allergy, it's all stress

Ok, so while the above statement isn't strictly true I was surprised at how much stress has to do with allergy. It is a well known, but oft ignored, fact that psychology has a big part to play in the disease process. Doctors have a natural reluctance to accept that physical illness can be affected by or even driven by the mind. We have been taught that a ligand binds to a receptor, which then causes a chain of reactions leading to the desired effect. We know that this system sometimes goes wrong and that sometimes we can fix it with drugs. When put like that it is easy to see why many doctors don't even consider psychology in their management.  Immunologists seem to be one group that have worked this out, although maybe not as far as getting to the management stage.

This article has been brought about because I am currently spending some time in an immunology department and have been seeing lots of allergy patients. The patients I am will be referring to in this article all have a few common factors. They are all adults who are presenting with a new onset allergy, usually urticaria or food allergy, and are/were suffering from stress. Three cases particularly stick out in my mind so I will run through them now.

1. Middle aged male. Presented with a 3 week episode of urticarial rash which occurred six months ago and has not happened since. He suspects it was due tired food colouring seeing as shortly after eating products with red food colouring the rash flared. This rash has not happened before and there is not other significant medical history. Interestingly the times he was suffering from the rash were in the build up to his wedding and it disappeared a few days into his honeymoon. 

2. Older lady. Presented with a four month history of angioedema which settled with antihistamines. She went as far as excluding most washing powders, toothpastes and several foods all to no avail. Had never had episodes like this before. The stress in her life was that her disability living allowance was going through the appeals process after she was deemed fit to work (which she clearly wasn't go other reasons).

3. Young lady. Two month history of diarrhoea after eating certain foods. Was on a severely restricted diet but was still having vomiting episodes. The onset coincided with her being made redundant. 

As you can see here are three cases where stress and allergy have a clear relationship. But you needn't take it on my word, it is well documented in the medical literature. When I asked a consultant about it he explained that the theory is that there is some sort of immunomodulatory effect. For example, it could be that the threshold level of IgE required to cause mast cell degranulation and histamine release is reduced. This then becomes a vicious cycle. As patients have more reactions they restrict their lives more, causing themselves more stress and anxiety. 

It seems very clear that there is a psychological link in the chain of hypersensitivity. The problem I saw was that nothing was being done about it. Clearly these patients would benefit from some sort of psychological intervention. Whether that be simply a consultation with a psychologist or a stress management course, surely something can be done for these people. Despite recognising stress as the most important trigger for the 'allergies' the consultant did nothing for them in the way of psychology. He simply prescribed antihistamines and sent them home. 

So we are left with patients who are having hypersensitivity reactions, but probably not related to any particular trigger. Even though the role of stress has been identified they are not receiving treatment for it. I wonder how long it will take for the doctors to see sense and start seeking psychology referrals for these patients, or even giving them simple stress coping advice. 

1 comment:

  1. I intercalated in immunology - so I agree, immunologists rock :P


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