Pityriasis rubra pilaris (type I) following ChAdOx1 COVID-19 vaccine: A report of two cases with successful treatment with oral isotretinoin.

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Dear Editor,

Pityriasis rubra pilaris (PRP) is a rare chronic papulosquamous dermatosis that can be triggered by multiple factors (e.g. drugs, infection) and influenced by a genetic background. PRP was also reported following vaccination (e.g. measles‐mumps‐rubella, oral poliovirus, diphtheria‐pertussis‐tetanus and influenza). Multiple cutaneous adverse events were associated with COVID‐19 and its vaccines, to date, there are four reports of PRP related to COVID‐19 vaccination. , , , Here, we report two cases of PRP after ChAdOx1 (AstraZeneca) vaccine, compare them with other similar cases and highlight a satisfactory response with oral isotretinoin.

Case 1; A 31‐year‐old man presented with itching salmon to erythematous scaly plaques on his upper trunk, upper and lower extremities for 60 days (Fig. 1a), sparing the periumbilical area, with palmoplantar keratoderma (Fig. 1b), without nail involvement. On 30 May 2021, he received the first dose of the immunization for SARS‐CoV‐2 with AstraZeneca vaccine. The patient noticed low fever and headache in the same day. After 10 days, he noticed a cutaneous rash on abdomen and face that progressed to dorsum, upper and lower limbs. There was no history of drug intake, except losartan 50 mg QD for systemic arterial hypertension during the past four years. Histopathological analysis was compatible with pityriasis rubra pilaris (Fig. 1d). The patient was treated with isotretinoin 30 mg QD and emollients for three months with total remission.

Figure 1

Clinical and histopathological features of PRP induced by COVID‐19 vaccination (ChAdOx1 ‐ AstraZeneca). (a) Case 1. Erythematous scaly plaques with areas of healthy skin; (b): Case 1. Plantar hyperkeratosis; (c). Case 2. Erythematous‐citrine scaly plaques all over the body with evident areas of healthy skin in the trunk; (d): Follicular plugging, alternating orthokeratosis and parakeratosis (vertical and horizontal), epidermis with broader rete ridges than expected in a psoriasiform reaction (HE, 200X).

Case 2; A 42‐year‐old man was vaccinated with two doses of AstraZeneca vaccine, without intercurrences. After 8 days of the second dose, scaly reddish plaques were observed on his face and then progressed all over the body in one week, leaving healthy skin areas, especially on the trunk, with a citrine colour (Fig. 1c), without nail involvement or palmoplantar hyperkeratosis. There was no history of drug intake or comorbidities. The histopathological analysis was analogous to the first case (Fig. 1d) and he was treated with isotretinoin 40mg/day in two months with partial clearance and then, 20mg/day in the third month with mild erythema.

The causal relationship between COVID‐19 vaccines and cutaneous immunological reactions is still not understood, but they can be due to an upregulated inflammatory immunological pathway or cross‐reactivity between vital or adjuvant molecules and self‐antigens.

Familiar cases of PRP revealed gain of function at CARD14 gene, which codifies the scaffold protein CARMA2, leading to the activation of (NF‐κB) by the complex CARMA2‐BCL10‐MALT1. As long as CARD14 can be induced by IL17 and PAMPS, inflammatory and infectious stimuli are thought to elicit PRP in genetically predisposed individuals.

The seven patients who developed PRP after COVID‐19 vaccination are listed at the Table 1. Their age varied from 31 to 82 years, both sexes were affected and different types of PRP have been presented. , , , Four patients presented the onset of adverse reactions in a mean time of 13 days after the first dose, , , one presented flare after the first and second dose and two of them after a medium of 6,5 days after the second dose. Four patients (57.14%) received (AstraZeneca), , one (14.28%) mRNA‐1273 (Moderna) and two (28,58%) BNT16B2b2 (BioNTech/Pfizer). ,

Table 1

Main characteristics of the reported patients with pityriasis rubra pilaris induced by COVID‐19 vaccines, , , , including our cases

Authors and country	Vaccine	Age (years)/ Sex (F, female; M, male)	Dose (1st/2nd) and time interval of first symptoms/signs	Treatment and prognosis
Criado et al. (Brazil)	ChAdOx1 (AstraZeneca)	31 y/M	1st, 15 days	Total clearance after 2 months of 20 mg/day oral isotretinoin and emollients
	ChAdOx1 (AstraZeneca)	42 y/M	2nd, 8 days	Total clearance after 2 months of 40 mg/day and then, 20 mg/day oral isotretinoin and emollients
Sechi, et al. (Italy) 3	mRNA‐1273 (Moderna)	62y/F	2nd, 5 days	Progressive remission with Prednisone (1 mg/kg/day for 2 weeks), then tapered until the use of topical corticosteroids
	BNT16B2b2 (BioNTech/Pfizer)	82y/F	1st, 7 days	Clinical improvement achieved with methotrexate 15 mg/weekly with residual scaly plaques on head and neck and PP hyperkeratosis after 4 months of follow up
Sahni, et al. (India) 4	ChAdOx1 (AstraZeneca)	72y/M	1st, 3 weeks	Total clearance after emollients and topical corticosteroids without recurrence after the 2nd dose
Lladó, et al. (Spain) 5	ChAdOx1 (AstraZeneca)	63y/F	1st, 9 days	Acitretin 20 mg/day; no follow up
Hunjan, et al. (United Kingdom) 6	BNT16B2b2 (BioNTech/Pfizer)	51y/M	1st, 3 days, and 2nd, few days after.	Improvement with acitretin 20 mg/day and topical corticosteroid

Despite the PRP might be, in most cases, persistent, in these series patients seem to improve mostly with retinoids but also with oral and topical corticosteroids. , , , The majority of cases occurred after the first dose, , , , but one had resolved prior to the second dose and there was no recurrence. These reactions occur in a close range of time (≤15 days), suggesting a pattern that could be linked to vaccination.

PRP can be elicited by COVID‐19 vaccination. , , , , Clinicians must be aware of this adverse event, probably facilitated by a genetic background, but prone to respond to treatment with a good prognosis.