Annular infectious dermatoses.

Annular configuration is conspicuous in the clinical manifestation of many skin diseases and can be helpful for the diagnosis and differential diagnosis. Variations may include arciform, ring-form, annular, circinate, serpiginous, gyrated, polycyclic, targeted or figurate forms, in different colors, sizes, and numbers, with various textures and surfaces. In infectious dermatoses, the annular reactions can be specific or nonspecific, while the underlying mechanisms remain largely unknown. In the specific reactions caused by direct invasion of the pathogens, the contest between the centrifugal outspread of the infectious agents and the centripetal impedance of the host immune response is supposed to determine the final conformation. Examples include erythema infectiosum, orf, erythema multiforme, and pityriasis rosea of viral origin. Bacterial infections that may display annular lesions include erythrasma, erythema (chronicum) migrans of Lyme borreliosis, secondary syphilis, cutaneous tuberculosis, and leprosy. Superficial mycosis, such as dermatophytosis, candida intertrigo, tinea imbricata, and subcutaneous mycosis, such as chromoblastomycosis, and algae infection protothecosis, are characterized by annular progression of the skin lesions. The creeping serpiginous extension is an alarming sign for the diagnosis of cutaneous larva migrans. A better understanding of the virulence and pathogenicity of the pathogens and the way and type of immune response will help to clarify the pathogenesis.

Biologics and small molecules in patients with scalp psoriasis: a systematic review.

BACKGROUND: Scalp psoriasis is common in psoriasis patients, difficult to treat and manifests a significant burden on quality of life. OBJECTIVE: Efficacy assessment of biologics and small molecules in scalp psoriasis with reported safety and quality of life. METHODS: Biological therapies and small molecules licensed for treatment of plaque psoriasis are assessed. Fourteen studies reporting results from RCTs are included. Efficacy assessment is measured through improvement of Psoriasis Scalp Severity Index (PSSI), Scalp Physician Global Assessment (ScPGA) and/or Scalp-Specific Investigator's Global Assessment (ss-IGA). RESULTS: Among biologics measured by PSSI, brodalumab, secukinumab and in a subgroup ixekizumab showed high efficacy in moderate to severe scalp psoriasis. Both brodalumab and ixekizumab demonstrated rapid response within 2 weeks. Guselkumab was superior to adalimumab and ixekizumab was superior to etanercept. Apremilast showed long-term efficacy. Only few studies reported quality of life in treatment of scalp involvement which showed improvement. All treatments demonstrated acceptable safety profile. CONCLUSION: Effective treatment of scalp psoriasis is essential for improving the quality of life of psoriasis patients. Both Biologics and small molecules proved efficacy. This review may help choosing the appropriate treatment in cases where scalp psoriasis is the main complaint. A unified measurement tool for scalp psoriasis severity is needed to facilitate comparisons.