The frequency and characteristics of itching in severe COVID‐19 patients: first report

Dear Editor,

Coronavirus continues to spread without slowing down, and the number of infected people has recently passed 90 million across the world. As of January 21, 2021, the COVID‐19 pandemic has resulted in 1,954,336 deaths in 220 countries. ¹ There are numerous reports regarding the dermatologic manifestations of COVID‐19. ² , ³ However, to the best of our knowledge, there is no adequate information about the frequency and characteristics of itching in COVID‐19. We investigated the frequency and characteristics of itching in patients with severe COVID‐19 at Uşak Training and Research Hospital. Severe COVID‐19 was determined according to the Turkish COVID‐19 guidelines. ⁴

A total of 168 adult patients who had lung involvement and were hospitalized because of COVID‐19 were recruited into this study. The onset of pruritus was defined no more than 3 days before admission to the hospital. Thirty‐three patients receiving medications, having itching‐related systemic diseases, scabies, dermatitis, xerosis cutis, or with a prior history of itching were excluded. Sixty‐one patients (45.2%) of 135 were females, and 74 (54.8%) were males. The mean age of the patients was 66.83 ± 13.09 years. There was no other cutaneous manifestation of COVID‐19 in the patients. The itching was seen in 10 (7.4%) patients. The average time for itching was 1.80 ± 2.39 days. The characteristics of the patients with itching symptoms are shown in Table 1. There was no statistically significant difference in the frequency of itching between females (6.6%) and males (8.1%) (P = 0.732). The mean age of patients with itching was 72 ± 11.68 years, while the mean age of those without itching was 66.42 ± 13.16 years. There was no statistically significant difference between the mean age of patients with and without itching (P = 0.128). Six (60%) of 10 patients had generalized itching while four had localized itching. The involvement sites of localized itching were hand, arm, shoulder, and scalp. Since all the patients had mild courses of pruritus, we took a wait‐and‐see approach for the management of pruritus. None of the patients required systemic antihistamine medication or any other treatment agents for pruritus.

Table 1.

The characteristics of itching symptoms in patients with severe COVID‐19

Number	Age (years)	Gender	Localization	Duration (day)
1	79	Female	Hands	<1
2	71	Female	Shoulders	<1
3	60	Female	Generalized	7
4	74	Female	Generalized	2
5	46	Male	Arm	<1
6	72	Male	Scalp	<1
7	80	Male	Generalized	2
8	87	Male	Generalized	1
9	80	Male	Generalized	1
10	71	Male	Generalized	5

This article is being made freely available through PubMed Central as part of the COVID-19 public health emergency response. It can be used for unrestricted research re-use and analysis in any form or by any means with acknowledgement of the original source, for the duration of the public health emergency.

The itching is associated with certain mediators such as histamine, leukotriene B4 (LTB4) which is a derivative of arachidonic acid, and cytokines including IL‐2, IL‐4, and IL‐13 and especially IL‐31. IL‐31 is one of the main cytokines in the pruritus that is produced by CD4 + T helper cells in the setting of IL‐4 secretion. In addition, IL‐31 is known as the part of the IL‐6 family that has both inflammatory and neuropathic properties. ⁵

In this study, we included COVID‐19 patients who had lung involvement and found the frequency of itching as 7.4% of patients. It is well known that numerous cytokines, such as IL‐2, IFNγ, IL‐6, and IL‐10, increase in patients with COVID‐19, especially in those who have severe lung involvement. ⁶ Although IL‐31 is not among cornerstone cytokines in COVID‐19, increasing of other cytokines, such as IL‐2, IL‐6, and IFN‐γ, may induce itching. Furthermore, secretion of arachidonic acids from lung cells, which results in the release of LTB4, may also contribute to the formation of itching. According to this study, although not statistically significant, itching was more common in older age and men compared to younger age and women. These properties are similar to the clinical characteristics of severe COVID‐19. In this context, it can be speculated that the itching in COVID‐19 may give some hints about the severity of the disease. However, itching in severe COVID‐19 had a mild course. Further studies are required in order to detect the properties of itching in COVID‐19.