There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Dear Editor,
Coronavirus disease 2019 (COVID‐19) pandemic continues to spread across the world
since early December 2019. To date, the number of confirmed COVID‐19 cases has exceeded
70 million according to WHO data. At the present time, Turkey is among the top countries
with highest daily new cases of COVID‐19.
1
Although hydroxychloroquine was the first recommended drug in COVID‐19 at the beginning
of the pandemic, nowadays, favipiravir is the most common recommended drug that is
used for COVID‐19 in Turkey. Currently, we observed numerous COVID‐19 patients who
have fingernail lunula luminescence under wood lamps. There are also some viral videos
on the Internet from UV‐based industry workers who previously had COVID‐19 that claim
fingernail lunula luminescence is a novel manifestation of COVID‐19 under UV light.
The current Turkish COVID‐19 treatment guideline recommends giving favipiravir 2 × 1600 mg/day
on the first day and then 2 × 600 mg/day for 9 days in symptomatic COVID‐19 patients.
2
According to our data, COVID‐19 patients not receiving favipiravir did not show luminescence
under the wood lamp. On the other hand, almost all patients receiving favipiravir
had fingernail lunula luminescence (Figure 1). The luminescence may last until 2 weeks
after the onset of the favipiravir. However, there should be a long‐term follow‐up
to detect the exact luminescence time.
Figure 1
Two real‐time polymerase chain reaction–confirmed COVID‐19 cases. A patient receiving
favipiravir (left) and a patient not receiving favipiravir (right)
Favipiravir is an anti‐viral agent that inhibits the RNA‐dependent RNA polymerase.
Its half‐life is about 5 hours. Favipiravir tablets have certain inactive ingredients
including titanium dioxide and yellow ferric oxide. Titanium dioxide and yellow ferric
oxidase have photostabilization effects to protect favipiravir from light sensitivity.
In addition, titanium dioxide and ferric oxides are strong absorbers of radiation
wavelengths below 365 and 400 nm, respectively.
3
,
4
These absorption wavelengths are related to both UV and wood lamp‐related wavelengths.
As it is known that peak absorption wavelengths of UVA and UVB lamps are under 400 nm.
In addition, barium silicate and 9% nickel oxide‐based wood lamp absorbs light between
320 and 360 nm with a peak at 365 nm.
Given these pieces of information, we believe that nail luminescence under UV or wood
lamps is not related the COVID‐19. Certain inactive ingredients such as titanium dioxide
and yellow ferric oxidase are the possible responsible agents for fingernail lunula
luminescence in COVID‐19 patients. Further studies are required to illuminate the
exact cause of fingernail lunula luminescence of COVID‐19 patients. Herein, we discussed
fingernail lunula luminescences under Wood and UV lamps in COVID‐19 patients.
CONFLICT OF INTEREST
None declared.