Smell is essential sensory function for good quality of life as its preservation helps in
identifying several harmful odors .

Viral URTIs can lead to olfactory disorders of varying degree and duration 70% of URTI
caused by rhinovirus, adenovirus ,influenza and parainfluanza virus Smell disorders are
divided into two types Quantitative (anosmia and hyposmia) Qualitative (parosmia and
phantosmia) Anosmia is a total loss of smell . hyposmia is a decrease in the sense of
smell. parosmia is a distortion of the smell in presence of an existing stimulus .
Phantosmia (Cacosmia) is distortion of the smell in absence of an existing stimulus
severe acute respiratory syndrome coronavirus2 (SARS-coV-2)which is a global pandemic
started in china 2019 one of respiratory tract infection that affect olfaction and cause
varying types of smell impairment.

Smell disorders seem to be more common in SARS-coV2 than other respiratory infections as
in some patient persist for long time after resolution of respiratory symptoms Current
evidence suggest that olfactory impairment results from propensity of SARS-coV2 for
neuroinvasion and neurotrophic activities .

Majority of patients experience some level of smell impairment most often temporary as
olfactory neuroepithelium has regenerative power .

European study published on 16 July 2020 reported that some patient affected by SARS
-coV2 come solely with olfactory symptoms and most of patient recovered within 2 weeks
,smell not recovered in one quarter of patient 15 Once olfactory dysfunction persists
more than 2 weeks a therapy should be considered to avoid persistent impairment of smell
One of therapies can be used in ttt of smell disorders ( Platelet _rich plasma) PRP is a
process in which a small amount of blood from test subject is separated by special
centrifugation process.

PRP contains many growth factor which have a neuroregenerative feature as well as
therapeutic effect