Background: The occurrence of acne in patients treated with Janus kinase (JAK) inhibitors for skin diseases is a potential issue, which may reduce treatment adherence.
Purpose: To systematically analyzes randomized clinical trials (RCTs) of JAK inhibitors in dermatological indications for the risk of acne as an adverse event.
Methods: A meta-analysis of odds ratios (ORs) for acne incidence was conducted. Data were quantitatively synthesized using random-effects meta-analysis. Surface under the cumulative ranking curve (SUCRA) values representing the relative ranking probabilities of treatments were obtained. Analyses were performed using R statistical software version 4.4.0.
Results: A total of 11,396 patients were included from 24 studies. The incidence of acne for JAK inhibitors was ranked according to the SUCRA as follows: JAK1 inhibitors > TYK2 inhibitors > combined JAK1 and JAK2 inhibitors > combined JAK1 and TYK2 inhibitors > JAK3 + TEC inhibitors > pan-JAK inhibitors. ORs were higher for longer durations of drug use and larger dosages. Subgroup analyses by disease indication revealed increased ORs for psoriasis (5.52 [95% CI, 1.39-21.88]), vitiligo (4.15 [95% CI, 1.27-13.58]), alopecia areata (3.86 [95% CI, 1.58-9.42]), and atopic dermatitis (2.82 [95% CI, 1.75-4.54]). The use of JAK inhibitors in patients with systemic lupus erythematosus (SLE) may not significantly increase the incidence of acne.
Conclusions: There are higher rates of acne following treatment with JAK inhibitors for dermatologic indications, particularly with longer durations and larger dosages. Pan-JAK inhibitors exhibit the lowest incidence of acne.

Numerous vaccines are under clinical development and implementation for the prevention of severe course and lethal outcomes of coronavirus disease 2019 (COVID-19). This systematic review aims to summarize and integrated the findings of studies regarding cutaneous side effects of COVID-19 vaccines. This systematic review conducted by searching the scientific databases of PubMed, Scopus, Science direct, and Web of knowledge from the beginning of the COVID-19 to May 10, 2021. Articles were reviewed and analyzed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Seventeen studies on cutaneous side effects of COVID-19 vaccines were included after the screening of search results based on to the eligibility criteria. The results showed that the most common injection site reactions and delayed large local reactions, arising from all vaccine types, were redness/erythema (39%), followed by: itchiness (28%), urticarial rash (17%) on the neck, upper limbs, and trunk, morbilliform eruptions (6.5%), Pityriasis rosea (3%), swelling, and burning, and so forth. Most cutaneous reactions occurred in women (84%), and middle-aged people, after the first dose of vaccine, with the onset ranged from 1 to 21 days after vaccination. In addition, cutaneous reactions were generally self-limiting, and needed little or no therapeutic intervention, that were not regarded as a barrier to injecting a second dose. In conclusion, severe cutaneous side effects are very rare and approved vaccines have satisfactory safety profiles. Therefore, mild or moderate cutaneous reactions should not discourage people from vaccination. In certain groups such as patients with allergies and a history of local injection reactions, pre-vaccination counseling and assurance, also use of appropriate medications may be helpful. However, more studies are needed to investigate the side effect profile of all COVID-19 vaccines.