Hyaluronic acid (HA) is a glycosaminoglycan, a natural component of the extracellular matrix. The identical structure of the molecule in all living organisms is its main advantage, as it translates into the minimal probability of immunogenicity. Therefore, it is the closest to the ideal preparation used as a filler, due to its biocompatibility and stability at the site of implantation. This paper includes the discussion of the potential mechanisms of adverse immune reactions to HA along with the mechanisms of reaction following vaccinations against SARS-CoV-2. Based on the literature, we tried to systematize adverse immune reactions with systemic manifestations to HA. The occurrence of unpredictable reactions to hyaluronic acid indicates that they may not be treated as neutral or non-allergenic. The modifications of the chemical structure of HA, additives and individual tendencies in a patient may be the cause of unpredictable reactions, leading to serious health consequences. Preparations of unknown origin, poorly purified, or including bacterial DNA are particularly dangerous. Therefore, long-lasting follow-up of the patient and the selection of a preparation approved by the FDA or EMA are of high importance. Patients are often unaware of the consequences of cheaper procedures performed by persons without suitable knowledge with the use of unregistered products, so the public should be educated and legal regulations should be introduced.

IntroductionMany recent epidemiological studies have shown the influence of treatment with anti-TNF-α on body mass of patients with psoriasis but there are no reports in the literature on the influence of ustekinumab on that parameter.AimTo review the effect of ustekinumab therapy on body weight in patients with psoriasis.Material and methodsThe examined group consisted of 11 patients with psoriasis treated at the Department and Clinic of Dermatology in Olsztyn. Patients’ body mass and body mass index (BMI) were evaluated prior to the first administration of the ustekinumab dose and at week 28 of treatment (the day of the fourth dose).ResultsBody mass increase was determined in 7 patients (64%), on average by 2.27 kg (p < 0.05), and the BMI increased by 3.35% (p < 0.1).ConclusionsObserving a correlation between ustekinumab application and body mass increase, similar to the treatment with anti-TNF-α preparations, an attempt was undertaken at explaining that correlation by analysing the role of IL-12 and IL-23 in psoriasis pathogenesis. IL-12 and IL-23, by influencing the naïve lymphocytes T and stimulating their diversification towards Th1 and Th17, also, indirectly, cause an increase in TNF-α and other cytokines production (IL-2, IFN-γ, IL-17, IL-10, IL-22). Ustekinumab will then have a significant influence on decreasing the production of cytokines, which are important for metabolism and body mass.

Under physiological conditions, skin mast cells play an important role as guardians that quickly react to stimuli that disturb homeostasis. These cells efficiently support, fight infection, and heal the injured tissue. The substances secreted by mast cells allow for communication inside the body, including the immune, nervous, and blood systems. Pathologically non-cancerous mast cells participate in allergic processes but also may promote the development of autoinflammatory or neoplastic disease. In this article, we review the current literature regarding the role of mast cells in autoinflammatory, allergic, neoplastic skin disease, as well as the importance of these cells in systemic diseases with a pronounced course with skin symptoms.

Cyclitols are widely available natural sugars which do not exert toxic effects. Their anti‐inflammatory and antioxidant properties may be used in the treatment of psoriasis. The aim of this placebo‐controlled, double‐blind study was to evaluate the clinical effects of D‐chiro‐inositol (DCI) in mild plaque psoriasis (46 psoriatic patients and 10 healthy volunteers). Three stable psoriatic plaques were selected for evaluation in every patient. Different samples were applied on each lesion twice a day: vehiculum without an active agent, containing 1% DCI and 0.25% DCI. The lesions were assessed using the PSI, VAS scale, and the objective measurement of hydration, transepidermal water loss (TEWL), elasticity, and thickness (DermaLab Combo) at 0, 3, and 6 weeks. PSI and VAS were improved in all groups without significant statistical differences. 1% DCI sample presented the highest statistically significant increase in the hydration of 50%, but it was still significantly lower than in healthy controls. TEWL increased for 1% DCI, which was a statistically significant difference compared to 0.25% DCI and still higher than in controls. An improvement in elasticity was observed in all lesions—it was statistically significant for 1% DCI. The thickness of the lesion decreased for 1% DCI, but the change was not statistically significant. Subepidermal low‐echogenic band showed a decreasing tendency in all groups, but it was not statistically significant. Favorable 1% DCI sample results indicate that it may be used as an adjuvant to the local treatment of psoriasis.

Botulinum toxin (BoNT) is a valuable therapeutic tool with several medical indications and the most popular of all cosmetic procedures worldwide. This is the reason for the growing number of unregistered products that may be the reason for adverse reactions. We present a case of a 51‐year‐old woman, who developed a pyoderma gangrenosum‐like reaction at injection sites after the administration of an unregistered BoNT product by a beautician. The clinical course, the morphology of the lesions, the result of histopathological biopsy, and the response to the treatment meets the criteria for diagnosis of pyoderma gangrenosum. The case presented by us is the first adverse reaction of this type after BoNT administration.