COVID-19 versus Allergic Rhinitis

COVID-19 is a new contagious, deadly viral/immunological systemic disorder with predominantly respiratory features caused by human infection with SARS-CoV-2, which is rapidly spreading from person-to-person all around the world as a pandemic, whereas, Allergic Rhinitis is an old non-contagious, non-deadly, and non-viral disorder with nasal inflammation which occurs when the immune system overreacts to allergens. Mild to moderate COVID-19 can be mistaken with Allergic Rhinitis. Fever, dry cough, dyspnea, fatigue, body ache, anosmia, and lack of taste are the cardinal feature of COVID-19, whereas runny nose, stuffy nose, sneezing, postnasal discharge, itchy eyes, and itchy skin are the cardinal feature of Allergic Rhinitis. Some of the cardinal feature of COVID-19 can be accessory feature of Allergic Rhinitis and vice versa. These two diseases are usually distinguishable by an expert physician. At the same time, an inexperienced physician will easily confuse them. The known cases of Allergic Rhinitis have allergies in this spring or year similar to previous years, not COVID-19, unless this time the symptoms are sudden, new, or more severe, and with previous conventional allergy treatment; don’t give up and get even worse. In fact, the mission of this article is to provide the easiest way to differentiate these two diseases. In the SARS-CoV-2 epidemics in the Red zones, when we cannot differentiate these two diseases; Allergic Rhinitis should be discarded in favor of COVID-19.


Introduction
The novel Coronavirus disease or COVID-19 is a new contagious, dangerous, and deadly viral/immunological systemic disorder with predominantly respiratory features caused by human infection with SARS-CoV-2, which is rapidly spreading from person-to-person all around the world as a pandemic, whereas, Allergic Rhinitis is an old non-contagious, non-dangerous, non-deadly, and nonviral/allergic non-systemic disorder with nasal inflammation which occurs when the immune system overreacts to allergens/irritants. These two diseases are similar in a significant number of clinical findings and they can easily be confused with each other, and this error can lead to irreparable damages, therefore, it is important to distinguish between the two diseases. In fact, the mission of this article is to provide the easiest/main way to differentiate these two diseases.

Method
Clinical and laboratory judgement of an experienced and knowledgeable physician in the field of these two diseases is the main method of distinguishing them from each other.  [4]. Lung involvement can be presented with high fever, severe dry cough, shortness of breath, sputum expectoration, chest pain, tachypnea, expulsion of blood along with intractable cough and cyanosis due to; pneumonia, pneumonitis, acute respiratory distress syndrome (ARDS), diffuse small vessel vasculitis, and respiratory failure. Many cases of COVID-19 with lung involvement require artificial respiration by ventilator machine and must go to the ICU, but they do not necessarily come out of the ICU alive [5] [6]. Other causes of death in COVID-19 are including; acute myocarditis, acute heart failure, acute myocardial infarction, cardiogenic shock [7] [8], acute renal failure due to acute tubular necrosis [9], hepatitis and hepatic failure [10], sudden cerebrovascular accident or stroke [11], and hemo-phagocytic lympho-histiocytosis (HLH) [12], Skin manifestations of cases with severe COVID-19 such as; erythematous rash, generalized urticaria, livedo-reticularis, petechial rash, acute generalized pustulosis, Raynaud imaging is limited to one lobe in one-third of cases and not seen at all in one-fifth of cases [16]. Elevated ESR/CRP along with low lymphocyte count and abnormal liver function tests are compatible with mild to moderate cases of COVID-19, but high level of LDH, very high blood ferritin, D-Dimer, blood oxygen saturation ≤ 93% and high serum level of IL-6 will be in favor of severe to critical cases [12]. We breathing and dark circle under the eyes, runny nose causes post nasal discharge which is why the patient repeatedly performs the maneuver of throat clearing, and frequent rubbing at the nose is due to itchy nose. It is called hay fever too, but you don't have to be exposed to hay to have symptoms, and hay fever does not necessarily cause fever. But it seems that the best name for this disease is

Discussion
Because COVID-19 can lead to dry coughs, runny nose, stuffy nose, sneezing, and fatigue it should be differentiated from Allergic Rhinitis. In Allergic Rhinitis, sneezing, runny nose, stuffy nose and postnasal discharge, itchy eyes, and itchy skin are most common, while in COVID-19; itchy eyes and skin are not seen and sneezing, runny nose, and stuffy nose are less common. Allergic Rhinitis do not cause weakness, body aches, tingling all over the body, fever, chills, and gastrointestinal features such as nausea, vomiting, diarrhea, abdominal pain, and bowel obstruction although they do occur in COVID-19, within fever is very common [17] [18] [19]. Shortness of breath, the loss of smell, and the lack of taste occasionally occur in Allergic Rhinitis, while they are very important findings in COVID-19 [22]. Intractable cough accompanied by expulsion of blood from lungs and cyanosis along with respiratory distress are seen in severe to critical cases of COVID-19, but they are not seen in Allergic Rhinitis. Tonsillitis and quinsy can be seen in COVID-19, but not in Allergic Rhinitis. Skin features such as; erythematous rash, generalized urticarial, livedo reticularis, petechial rash, acute generalized exanthematous pustulosis, Raynaud phenomenon, COVID-19 toes, acro-ischemic lesions, and extensive darkening of skin due to hemosiderosis in HLH secondary to COVID-19 can be seen in severe to critical COVID-19, but they are not seen in Allergic Rhinitis [13]. Severe headache, loss of speech, delirium, seizure, coma, loss of movement, stroke, meningitis, and encephalitis can be seen in severe to critical COVID-19, but they are not seen in Allergic Rhinitis [11]. Cardio-vascular involvements, acute renal failure, hepatitis and hepatic failure can be seen in severe to critical COVID-19, but they are not seen in Allergic Rhinitis [17] [18] [19]. Positive RT-PCR, positive Quick COVID-19 test, elevated ESR/CRP, low lymphocyte count, abnormal liver function tests, high serum level of LDH, ferritinemia, D-Dimer, blood oxygen saturation < 93%, and high serum level of IL-6 will be in favor of the diagnosis of COVID-19, whereas; high serum levels of IgE and blood/nasal eosinophilia are compatible with the diagnosis of Allergic Rhinitis [20] [21]. An abnormal lung imaging including each one of; GGO, crazy-paving pattern, consolidations, and linear opacities especially white lung is in favor of COVID-19, whereas, the lung imaging is usually normal in Allergic Rhinitis [16].

Conclusion
People with the past medical history of Allergic Rhinitis have allergies in this spring or year similar to previous years, not COVID-19, unless this time the symptoms are sudden, new, or more severe, and with previous conventional allergy treatment, don't give up and get even worse. These two diseases: COVID-19, and Allergic Rhinitis, have many common clinical findings, and it may be difficult to distinguish them clinically, so we usually need to use para-clinics to differentiate them from each other. Because COVID-19 is very dangerous, deadly, and pervasive, but Allergic Rhinitis is most often harmless; therefore, the corresponding author believes that in the SARS-CoV-2 epidemics in the Red zones, when we cannot differentiate these two diseases; Allergic Rhinitis should be discarded in favor of COVID-19. By this decision, we are preventing the spread of the SARS-CoV-2 epidemic as much as possible and significantly reducing COVID-19 mortality rate.

Author Contributions
ISA conceptualized the study, overall guidance, and manuscript writing. SK reviewed the manuscript draft.