First report in China! The disease is related to clothing disinfectant

Jingchu.com (Hubei Daily Online) (Reporter Huang Tao, Correspondent Zhang Mengshi, Qiao Lingling, Hu Bin) On March 4, the reporter learned from Wuhan First Hospital (Wuhan Hospital of Integrated Traditional Chinese and Western Medicine) that the hospital's dermatology department was the first in China to report "disinfectant benzalkonium chloride induced granular keratosis incompleteness", and many patients benefited from it. This achievement was recently awarded the hospital's Outstanding Medical Achievement Award.

Since 2022, the Department of Dermatology of Wuhan No. 1 Hospital has successively admitted a number of patients with flexural pellagra-like erythema as the main manifestation. The course of the disease ranges from 1 month to 1 year. The main sites of disease are located in the armpits, scapular area, waist, buttocks, groin, and around the female breasts. The primary rash manifests as erythema first and then desquamation. After local healing, erythema and desquamation recur. Some patients have been hospitalized for repeated treatment in multiple hospitals.

During the same period, domestic dermatologists have repeatedly initiated discussions on the diagnosis and treatment of similar cases: In previous years, we only saw one case every few years, so how come there are so many cases all of a sudden?

Chen Liuqing, director of the Department of Dermatology at Wuhan No. 1 Hospital, paid great attention to this and formed a team with many experts including Hu Bin, Su Fei, Huang Meng, and Xia Yun. They performed skin tissue biopsy, PAS staining, and direct immunofluorescence examination on the first seven patients and finally confirmed that they were suffering from Granular Parakeratosis (GP).

Literature search revealed that many foreign articles linked the disease to contact with clothing disinfectants containing benzalkonium chloride. After a detailed inquiry into the medical history, the expert team found that the confirmed patients had been exposed to disinfectant products containing benzalkonium chloride before the onset of the disease. The patients were then advised to stop using disinfectants, stop contacting disinfected clothing, and stop using all topical medications except moisturizers. After 4 to 6 weeks, the rashes of the patients all subsided, and no recurrence was found in subsequent follow-up.

Chen Liuqing reported the first case of axillary granular parakeratosis in the country in 2009. This time, after searching major domestic databases, Chen Liuqing and his team found that there were no similar case reports caused by benzalkonium chloride in China. In order to fill this knowledge gap, the team summarized the clinical and pathological characteristics of 7 patients. In April 2023, the team published the "Analysis of Clinical Characteristics of 7 Cases of Granular Parakeratosis after Exposure to Benzalkonium Chloride" in the form of a monograph in the "Chinese Journal of Dermatology", and published a popular science article for dermatology colleagues and patients on the online platform "The Secret Behind Disinfectants-From 7 Cases of Recurrent Pellagra-like Erythema". Many dermatology colleagues initiated exchanges after reading the article. One doctor said: "I also encountered two cases this year, and I haven't found the answer yet", "Our doctors have also encountered similar cases, and there is light on this question."

Chen Liuqing, director and chief physician of the Department of Dermatology at Wuhan No. 1 Hospital, said that when encountering erythema and wrinkled leaf-like scales in the intertriginous area in clinical practice, the possibility of this skin disease should be considered, and the correct diagnosis can be made by further questioning the medical history and understanding the history of contact with benzalkonium chloride. Patients develop a rash 3-4 weeks after contact with benzalkonium chloride, and the rash disappears 4 weeks after stopping contact, which is very close to the 28-day epidermal turnover time.

In the past year, the Department of Dermatology of Wuhan No. 1 Hospital has diagnosed nearly 50 cases of paragranular keratosis. Chen Liuqing reminded that patients with paragranular keratosis induced by benzalkonium chloride only account for a very small part of the users of this type of disinfectant. Among the same family members, even if the same washing machine is used to wash clothes, only one family member will have symptoms, indicating that there is a genetic susceptibility to this type of disease. Therefore, the value of benzalkonium chloride as a disinfectant should not be denied because of the appearance of a few cases of paragranular keratosis. Benzalkonium chloride is widely used in skin disinfectants and detergents. Since the outbreak of the new crown epidemic, the frequency of people using disinfectants has increased significantly, which may be one of the reasons for the increase in the incidence of paragranular keratosis.