CASE PRESENTATION
A 50-year-old female presented to the dermatology clinic for her initial
visit, with a concern of multiple dark spots on her skin. The patient
reported that approximately 1 year prior to presentation, she noticed an
erythematous tender patch on her left upper back 2 days following her
second dose of the Pfizer-BioNTech COVID-19 mRNA vaccine. Of note, both
doses of the vaccine had been administrated in her right arm. Over the
next several days, the lesion gradually lost its erythematous hue and
became a nontender round hyperpigmented patch. Approximately 1 month
later, she noticed similar tender erythematous plaques gradually
developing on her trunk and upper extremities. These lesions similarly
progressed to non-tender hyperpigmented patches over the next several
days. She continued to develop new lesions over the course of 9 months.
No bullous lesions were reported.
Her past medical history was notable for breast cancer treated with left
mastectomy and chemoradiation 3 years prior to presentation.
Additionally, she started taking amlodipine for hypertension 1 week
prior to presentation. She denied taking any other medications both at
the time of presentation and for the past year, including over the
counter medications such as acetaminophen or NSAIDs. She reported a
history of pruritus after taking a sulfa antibiotic many years prior to
presentation, but she did not remember the name of that medication. She
denied any history of vaccine allergies. Her family history was
noncontributory.
On examination, multiple round hyperpigmented patches ranging from 2 to
8 cm in size were seen on the left upper back (Figure 1a) ,
right forearm, right and left anterior chest wall ((Figure 1b) ,
left abdomen, and left axilla. The remainder of the cutaneous and
mucosal exam was unremarkable. A punch biopsy was obtained from the
round hyperpigmented patch on the left upper back. Histopathological
examination was notable for post-inflammatory pigmentary alteration with
rare eosinophils consistent with a resolving FDE (Figures 2a +
2b ). The patient was reassured and advised to weigh the potential
benefits and harms prior to receiving any booster doses of the COVID-19
vaccine.
DISCUSSION :
COVID-19 vaccination has been associated with an array of cutaneous
adverse effects, ranging from a localized pruritic erythematous eruption
to a case of Stevens-Johnson syndrome. FDE following Covid-19
vaccination has only been reported in a handful of cases [9]. The
pathogenesis of FDE following Covid-19 vaccination has yet to be
determined. One potential mechanism is an immune response to the
polyethylene glycol (PEG) excipient of the mRNA vaccine [8].
Similarly, a reaction to ChAdOx1 nCoV-19 virotopes in adenoviral
vectored vaccines [4] has been proposed as a possible mechanism.
Notably, polysorbate 80, the vaccine excipient, does not seem to be the
culprit allergen [4, 7].
FDE following COVID 19 vaccination appears to have a very low incidence
rate, and its outcome is generally favorable. However, our case
illustrates the potential for prolonged cosmetic sequelae following FDE
secondary to the Pfizer-BioNTech Covid-19 vaccination. As such, a clear
conversation about the risk of FDE should be included in the informed
consent discussion when weighing the risks and benefits of Covid-19
vaccination and booster doses.