Pityriasis rosea-like cutaneous eruption as a possible dermatological manifestation after Oxford-AstraZeneca vaccine: Case report and brief literature review.

Pityriasis rosea (PR) has been manifested in patients suffering from COVID-19 as well as after vaccine protocols against SARS-CoV-2. It has a possible association with the HHV-6B virus (roseola infantum) and can be controlled by antivirals such as acyclovir as well as by the amino acid l-Lysine that showed a positive result in reducing the number of lesions and healing time. The aim of this study was to report a case of PR after a second dose of Oxford-AstraZeneca, the adopted therapy and a brief literature review. A 53-year-old woman, phototype II, presented an erythematous lesion in the posterior right thigh 15 days after the second dose of Oxford-AstraZeneca vaccine. Eight days after the initial injury, new injuries appeared in the calf, buttocks and thighs. The diagnosis was PR with a 5-week eruption cycle. The treatment consisted of the use of l-Lysine, 3 grams loading dose and 500 mg for 30 days and moisturizing/healing lotion, starting 14 days after the herald patch. After the 5th week of the disease cycle, there were no new eruptions and the repair cycle continued for up to 8 weeks leaving some residual skin spots. It is concluded that the patient may be a carrier a latent virus, HHV-6, and the vaccine administration with immune system stimulation, would have activated the possible virus causing PR. l-Lysine helped to control the manifestation by limiting the number of lesions and their location, which were restricted to the legs, thighs and buttocks.

Synthesis of pH and Glucose Responsive Silk Fibroin Hydrogels.

Silk fibroin (SF) has attracted much attention due to its high, tunable mechanical strength and excellent biocompatibility. Imparting the ability to respond to external stimuli can further enhance its scope of application. In order to imbue stimuli-responsive behavior in silk fibroin, we propose a new conjugated material, namely cationic SF (CSF) obtained by chemical modification of silk fibroin with ε-Poly-(L-lysine) (ε-PLL). This pH-responsive CSF hydrogel was prepared by enzymatic crosslinking using horseradish peroxidase and H2O2. Zeta potential measurements and SDS-PAGE gel electrophoresis show successful synthesis, with an increase in isoelectric point from 4.1 to 8.6. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) results show that the modification does not affect the crystalline structure of SF. Most importantly, the synthesized CSF hydrogel has an excellent pH response. At 10 wt.% ε-PLL, a significant change in swelling with pH is observed. We further demonstrate that the hydrogel can be glucose-responsive by the addition of glucose oxidase (GOx). At high glucose concentration (400 mg/dL), the swelling of CSF/GOx hydrogel is as high as 345 ± 16%, while swelling in 200 mg/dL, 100 mg/dL and 0 mg/dL glucose solutions is 237 ± 12%, 163 ± 12% and 98 ± 15%, respectively. This shows the responsive swelling of CSF/GOx hydrogels to glucose, thus providing sufficient conditions for rapid drug release. Together with the versatility and biological properties of fibroin, such stimuli-responsive silk hydrogels have great potential in intelligent drug delivery, as soft matter substrates for enzymatic reactions and in other biomedical applications.