Reply to "Dermatoses caused by face mask wearing during the COVID-19 pandemic".

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Editor,

We read with interest the paper of Yu Olisova et al. recently published on JEADV about different dermatoses caused by face mask wearing during the COVID‐19 pandemic. The authors warned on the localization of lesions, typically observed only under the mask on cheeks, chin, and nasal bridge. We present a case series observed in our centre, which adds some hints of discussion.

Ten patients (four females and six males, aged 32–74 years) presented with psoriasis on retro‐auricular area induced by COVID mask. Eight of them were affected by psoriasis and received biological treatment, including etanercept (2/8 pts), adalimumab (2/8 pts), brodalumab (1/8 pt), ustekinumab (1/8 pt), secukinumab (1/8 pt) and guselkumab (1/8 pt). The patients had good control of the psoriasis with 5/8 patients with complete remission, while 3/8 patients presented a minimal residual psoriasis on the scalp and/or face. Two other patients were under adalimumab for Crohn’s disease (CD) and denied a history of psoriasis. All the patients reported that the skin manifestation had appeared after the use of ear‐looped masks, and all of them showed bilateral involvement of retro‐auricular area. Therefore, a diagnosis of retro‐auricular Koebner phenomenon (KP) was made in psoriatic patients, while a diagnosis of paradoxical psoriasis induced by KP was made in CD patients (Fig. 1).

Figure 1

(a, b) Retro‐auricular Koebner phenomenon in psoriatic patients wearing ear‐looped masks.

The KP, also known as isomorphic reaction, describes the appearance of new lesions induced by an injury on unaffected skin totally identical to the underlying cutaneous disease in a predisposed patient. This condition is well known in psoriatic patients. KP is strictly related to the underlying skin disease affecting the patient. It is usually of modest entity, although more severe forms have been reported. , In general, the management of the skin lesions induced by KP does not differ from the treatment of the underlying condition, although removing the cause represents the first step.

Our patients developed KP in the retro‐auricular area due to the prolonged use of ear‐looped masks. Interestingly, none of them had experienced KP before, not only in the retro‐auricular area or on the adjoining scalp, but neither anywhere on the whole‐body surface. The trauma causing KP may be mild, such as a scratch or injection, and the pressure exerted by the elastic of the mask behind the ear can be considered a minor injury, even though it is protracted over time.

Generally, koebnerization can be considered a clinical indicator of a relatively active or eruptive phase of the underlying dermatological condition. On the contrary, all our psoriatic patients were in a remission phase or showed minimal psoriasis, suggesting that even a minimal injury, if protracted, can induce a KP, also in psoriatic patients under treatment with total or almost total control of the disease. The use of ear‐looped masks induced a paradoxical psoriasis by KP in CD patients under anti‐TNFs. An increasing number of skin manifestations secondary to face mask use have been reported among health care workers and in the general population. Bothra et al. reported retro‐auricular dermatitis in individuals with prolonged use of ear‐looped masks.

Topical steroids were prescribed in all cases, but the treatment solved the problem only temporarily. Consequently, the patients were invited to use masks without ear loops or to position them on the occipital area and nape. We also suggested using gaiters in order to by‐pass the ears. After these changes in the use of the mask, all patients experienced retro‐auricular psoriasis remission.