Reply to "COVID vaccine-induced lichen planus on areas previously affected by vitiligo".

Conflicts of interest

The authors have no conflicts of interest to declare.

Dear Editor,

We have read with interest the letter by Piccolo et al. on COVID vaccine–induced lichen planus (LP) on vitiligo‐affected areas. Since the beginning of the immunization programs, COVID vaccine–induced rashes have been documented in several cases.

We report the case of a 29‐year‐old woman with vitiligo on her hands that appeared more than 10 years ago. One week after administration of Pfizer‐BioNTech COVID‐19 vaccine, she developed LP‐suggestive lesions on depigmented areas, which progressed after the second vaccine administration, involving skin areas not previously affected by vitiligo. At the time of consultation, erythematous, polygonal papules were seen on the dorsum of the hands, wrists, eyelids, submammary region, and lower extremities. Oral mucosa examination revealed reticular white marking and white plaques (Fig. 1).

Figure 1

COVID‐induced LP. (a, b) LP lesions on depigmented areas of both hands, (c) Reticular white plaques on oral mucosa. (d, e) LP lesions on normal skin of trunk and extremities.

The skin biopsy of abdominal lesions confirmed LP diagnosis, showing acanthosis and basal cell degeneration with civatte bodies and band‐like dermal lymphocytic infiltrate. Blood tests including biochemical and hematological parameters were normal. Antinuclear antibodies (ANAs) and serologies for hepatitis B, C, and HIV were negative. Topical clobetasol propionate and systemic prednisone were prescribed, with partial resolution of the lesions. Subsequently, treatment with methotrexate 10 mg a week was started with progressive improvement.

Considering the clinical and histopathological findings, and the onset and worsening of the skin eruption in relation to the COVID‐19 vaccine, diagnosis of vaccine‐induced LP was rendered.

The exact pathogenesis of the association of LP and COVID‐19 vaccinations is still unknown. A recent review of this association found 33 cases of LP arising after various vaccinations, including hepatitis B, influenza, and herpes zoster vaccines. It is known that LP dermatitis is induced by CD8+ cytotoxic T cells and maintained by the release of IL‐2, TNF‐α, and IFN‐γ by CD4+ lymphocytes. All COVID‐19 vaccines induce a T‐cell driven response with B‐cell activation, antibody production, and increased levels of cytokines, including IL‐2, TNF‐α, and IFN‐γ. ,

In addition to the case described by Piccolo et al, there are four other published reports of oral or cutaneous LP in association with COVID‐19 vaccination (Table 1). , , , , Here, we report a new case of LP triggered by COVID‐19 vaccination with development of cutaneous lesions, initially on vitiliginous depigmented areas, and subsequently on normal skin and oral mucosa. In our case, because of the clinical exacerbation following the administration of the second dose of the vaccine, immunomodulatory treatment with methotrexate was required. We encourage dermatologists to screen patients presenting with recent onset of dermatologic disease or sudden worsening of preexisting conditions to inquire about COVID‐19 vaccination to increase awareness in this particular area.

Table 1

Reported cases of lichen planus associated with COVID vaccination

	Sex/Age	COVID‐vaccine	LP onset	Successive doses	Type of LP	Diagnosis	Treatment
Troeltzsch M, et al. 5	Male/49 year	Ad26.COV2.S (Johnson & Johnson)	6 days after	NA	Oral	Oral mucosa biopsy	Topical clobetasol
Merhy R, et al. 6	Female/56 year	Pfizer‐BioNTech COVID‐19 vaccine	1 week after 1st dose	NR	Cutaneous	Skin biopsy	NR
Hiltun I. et al. 7	Female/56 year	Pfizer‐BioNTech COVID‐19 vaccine	2 days after 2nd dose	NA	Flare of preexisting cutaneous LP	Skin biopsy	High‐potency topical corticosteroids
Sharda P, et al. 8	Female /35 year	NR	2 weeks after	NA	Oral	Oral mucosa biopsy	NR
Piccolo V, et al. 9	Female 64 year	Pfizer‐BioNTech COVID‐19 vaccine	5 days after 1st dose	Recurrence	Cutaneous LP over vitiligo areas	Clinical findings	Topical and systemic corticosteroids
Present report	Female/29 year	Pfizer‐BioNTech COVID‐19 vaccine	1 week after 1st dose	Exacerbation	Cutaneous LP over vitiligo and normal skin areas	Skin biopsy	Topical and systemic corticosteroids methotrexate

NA, non‐applicable; NR, non‐registered.

Funding source

This article received no specific grant from any funding agency in the public, commercial, or not‐for‐profit sectors.