Allergies: A case of Itchy hives, sneezes and wheezes

Index Home

Today the word “allergy” is in common usage. This word was born quite recently in the year 1906. Clemens von Pirquet (1874–1929) was a paediatrician in Vienna. He and his peers were witness to new diseases that did not have much of an explanation. Some would develop transient itchy red patches on the skin (hives), others would sneeze for days. Sometimes, many would be affected in late-spring. Since this was also a time for grass-cutting or haying season, so it was popularly called as “Hay fever“. von Pirquet coined the word “allergy” for this phenomenon – allos for other, and ergia for action or force in Greek. Hence allergy was another, yet-unknown puzzling phenomenon. (I am yet to find a pirquet stamp, he does have a coin on his name !!)

While such allergic reactions, must have happened earlier – were quite unusual in medical history. Some theorists believe that increase in industrialization, urbanization, greater time-spent indoors, and exposure to new substances such as chemicals, preservatives, pets and moulds may have led to this rise. Others attribute this rise to more “hygiene” which is becoming more sensitive to some antigens (such as pollen), as we have less and less contact with others (such as bacteria). None-the-less allergies have indeed become more common in the 20th century.

Why do some react differently ?

Human body has an elaborate policing mechanism, to deal with invading microbes and variety of other antigens (or molecules). We know this as our immune-system. Immune systems of some individuals become more sensitive to certain molecules, and instead launch a “hypersensitivity” response. This response is governed by a different type of cells (mast cells), that particularly release a substance called histamine.

Histamine meets it nemesis

In 1910, a Brtish physiologist Henry Dale accidentally discovered histamine. Dale and Otto Loewi received 1936 Nobel Prize in medicine for discovery of chemical nerve transmitters. While we were trying to unravel complicated actions of histamine, we had our first anti-histamine in 1937. At this time Bernard Halpern (b1904) was a young medical graduate in search of a Job. He found employment at Rhône‐Poulenc lab in Lyon France, and by 1942 had synthesized Phenbenzamine – first anti-histaminic for human use.

Later, Halpern also synthesized most powerful anti-histamine (Promethazine or Phenargan) we use today. By 1970s we discovered more ways by which histamine would act. This action is in different tissues and pathways (H1, H2, H3 and now H4 receptors). These pathways have opened doors for newer anti-histamine medicines.

From Sneezes to Wheezes

While concept of Allergy is recent, both sneezes as well as wheezes are ancient. Ancient Greeks believed sneeze to be signal for divine endorsement. However, in middle ages sneeze was believed to indicate imminent death. Thus, began the practice of saying “bless you” after one had a sneeze. Across Asia, sneeze means that the person is being remembered by someone behind their back. Wiki even has a typical sneeze response listing, across various cultures.

Sneeze may be trivial, but wheeze is not. While wheeze is often equated with Asthma, it really is not. Ancient usage of word “Asthma” was for panting, or being breathless. Amongst various named “asthmas”, one we attribute to lungs is better termed as bronchial asthma – only remaining use of this word today. While most with asthma wheeze, a 1865 medical quote “All that wheezes is not asthma” is a popular medical-teaching point till date. Wheeze is an abnormal cry or a whistling sound, we may hear on breathing. This whistle comes from narrowed smaller wind-pipes or bronchioles. Asthma and many other conditions of lung can affect our wind-pipes, and hence this sound.

Most asthmas that begin in childhood are due to an allergy. While dust, pollen, hay or mite are common allergens – this is a growing list. In 1970s, many countries in Europe and North America had a dramatic rise in allergic asthma. Other Low and middle income countries seem to be following this trend.

End game in sight ?

As of today, no end game for allergies is in sight. We do-not know well, why some Immune systems are more tolerant than others. The aggressive ones, fight the allergen hard and also tend to harm themselves in the process. Behaviour of immune systems is sometimes similar to human societies over the years !!!!