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We have all experienced it: you are trying to write a word, but suddenly do not remember the correct spelling. None of the versions you write down looks right, and you end up googling it to find out the spelling you have been looking for. You are definitely not alone. This is so common it even has a name: wordnesia.

Wordnesia is not the only reason why someone might have a hard time spelling a word. When a certain term is commonly misspelt, all spellings suddenly seem kind of right, since you have actually seen all of them in use. Although misspelling might not seem to affect the general message of a text, in medical writing it may have severe consequences. Misspelt words make the expert reader doubt the author’s competence and potentially confuse a more general audience. Moreover, during literature review, researchers may reject or overlook an article due to the misspelling of a keyword.

Two medical conditions are especially commonly misspelt or mistranslated, as most people working in healthcare and pharmaceuticals will recognise. This blog post explains why that is, and how to spell them correctly.

Stevens-Johnson syndrome

Commonly listed among the (rare) side effects of many medications and some illnesses, Stevens-Johnson syndrome seems to be a tough nut to crack. Being comprised of two proper names, the structure of the term is complex and easy to spell incorrectly.

The disorder was named after Albert Mason Stevens and Frank Chambliss Johnson, two American paediatricians, who signed their names under their description of it in the American Journal of Diseases of Children in 1922.

Many of the issues with spelling stem from the way the disease was named. As you may know, the combination of an apostrophe and letter s (’s) in English denotes possession, so many may understand the privilege of naming a disease as right to possession – resulting in misspelling examples 1 and 4 below. Additionally, some authors erroneously think the last name of Mr Frank Chambliss was Johnsons, leading to the misspellings in example 2 and 5 below.

Orthography is another problem: the length of the dash between the two last names, as in examples 3–5 below. Namely, three basic lengths of dashes are used in English writing: a short one (-), called ‘hyphen’, a longer one (–), called ‘en dash’, and a very long one (—), called ‘em dash’. The first two are very common, but all three serve distinct purposes, and are not interchangeable. In the case of Stevens-Johnson syndrome, the hyphen should be used, as hyphens are usually placed between words to form a single concept.

So far, we have encountered the following incorrect spellings:

  • Stevens-Johnson’s syndrome
  • Stevens-Johnsons syndrome
  • Stevens–Johnson syndrome
  • Stevens–Johnson’s syndrome
  • Stevens–Johnsons syndrome

In short: the only correct spelling of this disease is Stevens-Johnson syndrome.

Lapp lactase deficiency

Lapp lactase deficiency is a rare hereditary condition; people who have it find it difficult to digest lactose, i.e. have lactose intolerance. Why is this condition not simply called “lactase deficiency”? The symptoms of both conditions are similar but not their origin. The inhabitants of Lapland (a region stretching across Northern Sweden, Finland and Norway) the Sami people used to be called Lapps. Lapp is now considered a derogatory term, so some would say it is racist and should not be used. Lapp lactase deficiency is still used as the name for a form of lactose intolerance that Sami people developed due to insufficient genetic distance.

Lapp lactase deficiency is mentioned on the package leaflet of practically every medicinal product containing lactose. Terminologically speaking, the meaning commonly leads to mistranslations. English can be an incredibly concise language and phrases can consequently be ambiguous. Lapp lactase deficiency can be described in plain language as “lactase deficiency typically observed among the Sami (formerly called Lapp) people”.

The problem arises if the translator does not know what “Lapp” means. It could be the surname of a person or institution that discovered this condition (like Stevens-Johnson syndrome). In each of these cases, the translation would be different – and wrong. In the mistranslations below, the translator thought “Lapp” was a proper name. In the second French example, the translator even thought there was a type of lactase called “Lapp lactase” that a person could have a deficiency from.

  • Spanish: insuficiencia de lactasa de Lapp
  • Italian: deficiência de lactase de Lapp
  • French: déficit en lactase de Lapp or déficit en Lapp lactase

And how should “Lapp lactase deficiency” be translated, taking into account the geographical etymology of the word “Lapp”?

  • Spanish: insuficiencia de lactasa de los lapones, insuficiencia de lactasa propia de los lapones
  • French: déficit en lactase propre des lapons, déficit en lactase propre des populations lapones
  • Italian: carenza di lattasi propria dei lapponi, carenza di lattasi propria della popolazione lappone
  • Slovenian: laponska oblika zmanjšane aktivnosti laktaze

Are there any other medical terms that you find commonly mistranslated or misunderstood? We would be delighted to know them and pay special attention to them in our translations. You can always reach us at