I
recently came across an article that told the story of two siblings who are
allergic to the cold, literally! At
first, I was drawn to the article because I have never heard of this type of
allergy before, but as I continued to read, I realized how devastating and
challenging it is for those with this condition to live normal lives. These siblings have a rare condition called cold urticaria that only affects one in
100,000 people. The cause may be
extra sensitive skin receptors due to an inherited trait, or certain autoimmune
diseases, infections, or a side effect of a medication. Several genetic mutations are currently under
investigation, including deletions in the PLCG2 gene, which regulates elements
of the phospholipase-c signaling pathway (Ombrello, 2012).
This pathway activates second messenger molecules that alter various
cell responses, such as cell proliferation and differentiation. The exact mechanism of this pathway in cold urticaria and the cause in general is unclear, though, which
makes diagnosis and treatment very difficult.
Symptoms
include hives, itchiness, rash, swelling of the area of contact, and in severe
cases, life-threatening anaphylaxis.
Some reactions can be especially dangerous if there is full skin
exposure to cold, such as swimming in cold water. These symptoms are caused by mast cell
degranulation, and in the case of severe reactions, large amounts of histamine
are released and can cause a sudden drop in blood pressure that can ultimately
lead to fainting, shock, or death.
A
reaction typically occurs when there is exposure to temperatures below 40 F,
but it is harder to escape the cold than you may think. Some unexpected triggers of cold urticaria include
cold countertops, holding a chilled coke can, popsicles, walking barefoot on hardwood
floors, and even “running and getting sweaty against the air” (Elaridi, 2012). The “ice cube test” is used to diagnose cold
urticaria by placing an ice cube on the patient’s forearm for 10 minutes, and
waiting for a hive or swelling to appear after about 5 minutes after the ice
cube is removed (indicating a positive test).
 | |||
| A positive ice cube test (http://www.nejm.org/doi/full/10.1056/NEJMicm072431) |
There
are several different forms of cold urticaria that do not have a positive ice
cube test, including: delayed cold
urticaria (symptoms occur 12-48 hours of cold exposure), cold-dependent dermatographism (symptoms
only occur with pressure on cold skin), cold-induced
cholinergic urticaria (symptoms occur with exercise in cold environments),
and localized cold reflex urticaria
(symptoms occur away from area of direct cold exposure). A disease called cholinergic urticaria is caused by opposite conditions, where heat
exposure causes similar symptoms. This variation in symptom onset and location greatly contributes to the difficult diagnosis of this disease.
There is no cure
for this condition, but symptoms can be treated with strong antihistamine
medications. The main course of
treatment for these patients is to avoid cold exposure, but for the siblings in
the article who happen to live in Colorado, this will be an even greater
challenge.
References:
Elaridi, F. (2012, November 15). Kids Allergic to the Cold - Literally. ABC News.
Retrieved November 21, 2012, from
http://gma.yahoo.com/blogs/abc-blogs/kids-allergic-cold-literally-203616484--abc-news-health.html.
Ombrello, M., Remmers, E., Sun, G., & Freeman, A. (2012). Cold urticaria, immunodeficiency, and autoimmunity related to
PLCG2 deletions. The New England Journal of Medicine, 366, 330-338.
I found this blog post very interesting and relevant because all of us soon-to-be medical professionals need to be aware of substances and conditions that may cause an allergic reaction in an individual. I thought it would be interesting to find other "exotic" allergies and came across a few inciting ones: some people who are allergic to raw foods like fruits or vegetables may not actually be allergic to the food but the dirt or tree/weed pollen on the fruit, called oral allergy syndrome. The allergy to chocolate (how terrible, by the way. I love chocolate!) may be due to food additives or insects that may find their way into the chocolate. Finally, the allergy to touch, called demographism, is caused by weak membranes in the skin which cause a person to break out in hives after being touched. Demographism is usually treated with antihistamines, like Katie mentioned for the treatment of cold urticaria. Fortunately with the aid of modern medicine, it sounds like one antihistamine pill a day would allow an individual with either cold urticaria or demographism to live a normal histamine-free life.
ReplyDeletehttp://www.huffingtonpost.ca/2012/03/19/strange-allergies_n_1363057.html#s793334&title=Touch
I found an article about Familial Cold Autoinflammatory Syndrome (FCAS). It is a case study, with a Japanese patient who presented all the symptoms you describe in your blog; however, the ice cube test result was negative. I thought this was interesting because it seems like there is a dose-dependent trigger for the urticaria, and for certain symptoms to occur. According to the article, in FCAS they identified the mutation in the CIAS1 gene, encoding a cryopyrin protein expressed mainly in phagocytic cells, and they also identified a missense mutation in the gene (Kanegane 2008). Have you found any other mutations that could increase the prevalence of Cold Urticaria in families, and certain populations?
ReplyDeleteKanegane, H., et al. (2008). A CIAS1 mutation in a Japanese girl with familial cold autoinflammatory syndrome. European Journal Of Pediatrics, 167(2), 245-247.