Literature Search

As shown in Fig. 1, 367 studies were identified after searching four major databases and performing a manual search of the reference lists of identified studies. We excluded 172 studies as duplicates, and 93 studies were excluded for being unrelated to the study question after assessing the title or abstract. The full texts of the remaining 102 studies were reviewed, and 43 studies were identified as meeting the inclusion criteria for qualitative synthesis. A total of 7 studies reporting new-onset psoriasis, 32 studies reporting psoriasis flares, and 4 studies reporting both new-onset psoriasis and psoriasis flares were included in this study (Tables 1, 2).

Fig. 1

PRISMA flowchart of the selection of studies

Table 1 Characteristics of the included studies reporting new onset psoriasisTable 2 Characteristics of the included studies reporting psoriasis flarePatient Characteristics

Detailed information on the included patients is presented in Tables 1 and 2. The characteristics of the included studies are summarized in Table 3. The new-onset group consisted of 35 patients, mostly from America, ranging from 23 to 79 years in age. Most studies did not document patient sex, but among those that did, women slightly outnumbered men. The majority of patients presented with plaque psoriasis (17 patients), followed by guttate psoriasis (10 patients), and generalized pustular psoriasis (GPP) and nail psoriasis were reported in two patients and one patient, respectively.

Table 3 Summary of characteristics of the included studies

The flare group consisted of 279 patients, ranging from 20 to 84 years in age, who mostly experienced plaque-type psoriasis, followed by pustular, guttate, and erythrodermic psoriasis and PsA. Approximately 52% of patients were from Asian countries, followed by America (25%) and European countries (23%). The youngest patient was 20 years of age and developed pustular psoriasis, but the majority of cases were middle-aged or older patients. Similar to the new-onset group, most studies did not report patient sex, but among those that did, women slightly outnumbered men.

Vaccine Type, Vaccine Dose, and Psoriasis Onset Time After Vaccination

In the new-onset group, 14% of patients were administered the BioNTech/Pfizer vaccine [27, 29, 33,34,35], 6% were administered the Moderna vaccine [14, 28], and 6% the AstraZeneca vaccine [5, 36], although the vaccine type was not reported for the majority of patients [9, 37]. The vaccine dose was only reported for eight patients [5, 27,28,29, 33,34,35,36], with four new-onset psoriasis cases reported after patients received the second vaccine dose [5, 27, 28, 34], and four cases reported after the first dose [29, 33, 35, 36]. A wide range of onset times was observed, ranging from 2 to 21 days following vaccination [33, 36]. The longest onset time was observed in a patient with new-onset GPP [36], with the majority of new-onset psoriasis cases presenting 1–2 weeks following vaccination.

In the flare group, most patients received mRNA vaccines (28%) [8, 10,11,12, 28, 38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58], with the BioNTech/Pfizer vaccine (20%) reported more often than the Moderna vaccine (7%), followed by the AstraZeneca vaccine (7%) [5, 10, 12, 26, 38, 50, 59] and the Sinovac vaccine (1%) [41, 60]. Flares were most commonly reported following the second vaccine dose (23%) [5, 10, 12, 38,39,40,41,42,43,44, 49,50,51, 55, 56, 58], followed by the first vaccine dose (7%) [10,11,12, 26, 28, 38, 39, 48, 50, 53, 54, 59], both the first and second doses (2%) [38, 52], and the third dose (1%) [8, 39]. The onset time in the flare group ranged from 1 day to 90 days. The shortest onset times were reported for a 40-year-old man who experienced a GPP flare following the AstraZeneca vaccine and a 58-year-old woman with erythrodermic psoriasis following the first dose of the BioNTech/Pfizer vaccine [26, 53]. The longest onset time was reported for a 27-year-old woman who experienced a psoriasis flare after the second dose of the BioNTech/Pfizer vaccine [9].

History of COVID-19 Infections or Potential Non-Vaccine Triggers

Most patients denied the possibility of other non-vaccine triggers in both the new-onset and flare groups. However, previous COVID-19 infections were identified in six patients who experienced psoriasis flares after receiving the Moderna and BioNTech/Pfizer vaccines [9, 61]. Similarly, in one patient with new-onset nail psoriasis, a history of asymptomatic SARS-CoV-2 infection 6 months prior to vaccination was reported [27]. One patient who experienced a GPP flare after receiving the AstraZeneca vaccine had a history of experiencing psoriasis flares, with prior triggers including upper respiratory infection, trauma, and pregnancy [26]. An association between COVID-19 vaccination and psoriasis flares was highly suspected, but the study was limited by its retrospective design, and a causal relationship could not be determined [26].

Skin Manifestations, and Laboratory Studies

Typical psoriatic skin manifestations were reported for each psoriasis subtype in both the new-onset and flare groups. Only three studies documented the severity of new-onset psoriasis [5, 9, 27]. A patient who experienced new-onset nail psoriasis was reported by Ricardo and Lipner, characterized by nailfold erythema and degenerative changes in the small joints of the hands after receiving the second BioNTech/Pfizer vaccine dose, with a nail psoriasis severity index (NAPSI) of 18 points [27]. Two cases of new-onset psoriasis involving body surface areas (BSAs) of 30% and 60% were reported after the second AstraZeneca and Moderna vaccine doses, respectively [5, 9]. The severity of psoriasis flares was reported by 15 studies according to either PASI or BSA [8,9,10, 12, 26, 28, 40, 41, 46, 50, 55, 58, 61], ranging from PASI 2.1 to 48.6 and BSA 2–95%.

In the new-onset group, laboratory studies were only reported in three cases, including two cases with guttate psoriasis and one case with GPP [28, 33, 36]. In the two cases with guttate psoriasis, one patient presented with an elevated C-reactive protein (CRP) level [28], whereas the other patient was reported to have a CRP level and an erythrocyte sedimentation rate (ESR) within the normal limits [33]. No patients presented with elevated anti-streptolysin O (ASLO) titers, and a throat culture performed in the case reported by Pesqué et al. [28] was negative. Twelve studies including 14 patients in the flare group documented laboratory findings [