Koplik Spots

Clinically described as resembling “grains of salt on a red background,” these enanthems are a crucial early diagnostic sign that facilitates preemptive isolation and control of one of the most infectious viral diseases known to medicine.

Koplik spots remain a valued clinical sign — especially during outbreaks or in settings where access to confirmatory testing is limited — and are frequently referenced in paediatrics, infectious diseases, and public health literature.

Though eponymously associated with American paediatrician Henry Koplik (1858–1927), despite earlier descriptions predating his 1896 publication. Koplik’s contribution lay in emphasizing the diagnostic significance of these lesions during the pre-eruptive phase of measles, thus marking a turning point in early measles diagnosis and public health management.

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History

1854 (possible) – Reubold (Würzburg) may have been the earliest to mention intraoral lesions associated with measles, though sources are inconsistent.

1874 – Carl Jakob Adolf Christian Gerhardt (1833–1902) reportedly noted buccal enanthems in measles. Gerhardt mentions early mucous membrane involvement in measles, though the lesions were not identified as pathognomonic or with precision

1879 – Nikolai Flindt (1843-1913) described spots on the palate and buccal mucosa, though without distinguishing them diagnostically.

1895 – Russian pediatrician Nil Fyodorovich Filatov (1847-1902) published a description of buccal mucosal spots in measles prior to the appearance of the rash. These lesions, though not clearly defined as pathognomonic, were later termed “Filatov spots” in Russian medical literature.

Filatov described точечные серовато-белые высыпания на слизистой оболочке губ и щек, pinpoint grayish-white eruptions on the mucous membrane of the lips and cheeks, during the catarrhal period, 1–2 days before the onset of the skin rash

1896 – Henry Koplik (1858–1927) published “The diagnosis of the invasion of measles from a study of the exanthema as it appears on the buccal mucous membrane” in Archives of Pediatrics, highlighting “minute bluish-white specks” as pathognomonic for early measles.

If we look in the mouth we see…a few spots on the soft palate. On the buccal mucous membrane and the inside of the lips, we invariably see a distinct eruption. It consists of small, irregular spots, of a bright red color. In the centre of each spot, there is noted, in strong daylight, a minute bluish whites peck. These red spots, with accompanying specks of a bluish white color, are absolutely pathognomonic of beginning measles, and when seen can be relied upon as the forerunner of the skin eruption

…the buccal eruption is of the greatest diagnostic value at the outset of the disease before the appearance of the skin eruption

Koplik 1896

1899 – Koplik reinforced his claims in a second publication (1898) and third (1899) with an illustration, further clinical observations. He emphasised differences between his sign and other enanthems and increased the differential diagnosis to exclude erythema multiforme, catarrhal angina and drug rashes. He provided brief clinical details of 16 measles patients, 8 of whom were seen early enough to recognise the spots

It will be seen that in the spots which I have described the profession has a pathognomonic sign of measles at an early stage of the disease of the highest diagnostic value. It enables one to isolate the measles patients with certainty at a much earlier period than was formerly possible. Epidemics both in hospitals and institutions can be promptly limited if not aborted. At the same time, one has a means of distinguishing measles from a variety of similar eruptions of the skin resembling the measles exanthema.

Koplik 1899

1901 – Debate around priority continued; English-language clinicians often adopted “Koplik spots,” while Russian and some European sources credited “Filatov”.

20th Century – Koplik’s sign became embedded in textbooks (e.g., Nelson’s Pediatrics) as a classic early indicator of measles.

21st Century – Koplik spots remain key in outbreak control and appear in WHO, CDC, and textbook guidelines; diagnostic relevance continues despite the availability of molecular testing.

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Associated Persons

• Carl Gerhardt (1833–1902) – German internist; noted oral signs in measles as early as 1874.
• Nikolai Flindt (1843-1913) – Danish physician; described mucosal lesions in 1879
• Nil Fyodorovich Filatov (1847-1902) – Russian paediatrician; independently observed similar intraoral lesions in 1895
• Henry Koplik (1858–1927) – American paediatrician; described the enanthem now bearing his name; emphasized its early diagnostic utility in measles.

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Alternative names

• Koplikshe Flecken
• Flindt-Koplikshe Flecken
• Flindt-Koplik spots
• Filatov spots
• Belsky–Filatov–Koplik spots

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References

Original articles

• Filatov NF. Otdel’nye formy korovyh zabolevanii [Distinct Forms of Measles Disease]. Russkii Vrach [The Russian Physician], 1895
• Koplik H. The diagnosis of the invasion of measles from a study of the exanthema as it appears on the buccal mucous membrane. Archives of Pediatrics, New York, 1896; 13: 918-922. [Classic Re-Print 1997]
• Falkener L. Filatow’s Spots in Morbilli. Lancet 1901; 157(4040): 315-317

Review articles

• Markel H. Henry Koplik, MD, the Good Samaritan Dispensary of New York City, and the description of Koplik’s spots. Arch Pediatr Adolesc Med. 1996 May;150(5):535-9
• Baxby D. The diagnosis of the invasion of measles from a study of the exanthema as it appears on the buccal mucous membrane. Rev. Med. Virol. 1997;7:71–74
• Steichen O, Dautheville S. Koplik spots in early measles. CMAJ. 2009 Mar 3;180(5):583.
• Markel H. Koplik’s Spots: The Harbinger of a Measles Epidemic. Milbank Q. 2015 Jun;93(2):223-9.
• Н.Ф. Филатов важный диагностический признак кори. Справочник о здоровье человека