New described dermatological disorders

Aquaporin-3 in the epidermis: more than skin deep

The skin is essential for terrestrial life. It is responsible for regulating water permeability and functions as a mechanical barrier that protects against environmental insults such as microbial infection, ultraviolet light, injury, and heat and cold, which could damage the cells of the body and compromise survival of the organism. This barrier is provided by the outer layer, the epidermis, which is composed predominantly of keratinocytes; keratinocytes undergo a program of differentiation to form the stratum corneum comprising the cornified squame "bricks" and lipid "mortar." Dysregulation of this differentiation program can result in skin diseases, including psoriasis and nonmelanoma skin cancers, among others. Accumulating evidence in the literature indicates that the water-, glycerol-, and hydrogen peroxide-transporting channel aquaporin-3 (AQP3) plays a key role in various processes involved in keratinocyte function, and abnormalities in this channel have been observed in several human skin diseases. Here, we discuss the data linking AQP3 to keratinocyte proliferation, migration, differentiation, and survival as well as its role in skin properties and functions like hydration, water retention, wound healing, and barrier repair. We also discuss the mechanisms regulating AQP3 levels, localization, and function and the anomalies in AQP3 that are associated with various skin diseases.

Erythema papulatum centrifugum and new diagnostic criteria

Erythema papulatum centrifugum (EPC), also known as erythema papulosa semicircularis recidivans (EPSR), is distinct from eczema and other well-described figurate erythemas characterised by annular erythematous lesions. We report 7 cases of EPC and propose new diagnostic criteria including the following: (i) EPC is characterised by single or multiple recurrent expanding annular or semi annular erythema with central regression, surrounded by tiny red papules; (ii) the lesions regularly relapse and resolve; (iii) the histopathologic feature shows superficial perivascular inflammation with or without mild inflammation around sweat glands in the mid dermis and (iv) patients lack other associated cutaneous or internal abnormalities.

Disease course and treatment effects of a JAK inhibitor in a patient with CANDLE syndrome

BACKGROUND

CANDLE syndrome (an acronym for Chronic Atypical Neutrophilic Dermatosis with Lipodystrophy and Elevated Temperature) is a recently described rare autosomal recessive disorder charaterized by systemic autoinflammation. Clinical manifestations include presentation in the first year of life, episodes of fever accompanied by erythematous skin lesions, progressive lipodystrophy, violaceous periorbital swelling and failure to thrive. This syndrome is caused by loss of function mutations and malfunction of the immunoproteasome complex. Most patients have biallelic mutations in the PSMB8 gene that encodes the β5i catalytic subunit of the immunoproteasome. Examples of digenic inheritance have been also described in CANDLE. CANDLE patients have strong type I interferon gene expression signature and they are responsive to treatment with JAK inhibitors. However, possible serious side-effects remain a concern. Here, we report another patient with CANDLE whose disease activity was well controlled by the treatment with baricitinib.

CASE PRESENTATION

We report a Bulgarian patient of the Turkish ancestry who carries biallelic mutations in the PSMB8 gene: p.Ala92Val and p.Lys105Gln. The pathogenic variant p.Ala92Val has not been previously described in patients with CANDLE. We also comment on the unusual feature in this patient, nephrolithiasis, that has not been described in other patients, however it might be related to the positive family history for kidney stones. We have treated the patient with the JAK inhibitor baricitinib for the past year and we observed a significant amelioration of his inflammatory episodes, skin and joint manifestations, and improvements in physical activities and growth. The treatment with glucocorticoids (GC) was completely discontinued. No side effects have been observed, however they remain in consideration for a life-long therapy of this disease.

CONCLUSIONS

CANDLE should be suspected in patients with early-onset systemic inflammatory disease and prominent skin manifestations. Molecular testing can confirm the clinical diagnosis and is very important in guiding therapies. Treatment with JAK inhibitors is highly efficacious and appears to be safe in children with CANDLE and other intereforonopathies.

[Severe acne in autoinflammatory diseases]

BACKGROUND

In recent years, acne has been described as a symptom of autoinflammatory diseases, such as PASH (pyoderma gangrenosum - PG, acne and suppurative hidradenitis - SH) and PAPASH (PG, acne, pyogenic arthritis, and SH). The pathogenesis of autoinflammatory diseases is not fully understood; however, based on the possible involvement of IL-1β, the recombinant human interleukin-1 receptor antagonist anakinra has been used in the treatment of certain autoinflammatory diseases.

METHODS

We describe two patients with severe acne and associated symptoms which led to the diagnosis PAPASH and PASH syndrome and who were treated with anakinra.

RESULTS

In the patient with PASH syndrome, inhibition of inflammation and almost complete healing of ulcers was observed. In the patient with PAPASH syndrome, partial response was achieved.

CONCLUSION

The therapeutic effect of anakinra in PASH syndrome and partly in PAPASH syndrome indicates an involvement of IL-1β in acne-associated autoinflammatory diseases.

CANDLE syndrome: chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature-a rare case with a novel mutation

We described herein a patient with chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome and a novel mutation in PSMB8 gene. This patient had multiple visceral inflammatory involvements, including rare manifestations, such as Sweet syndrome and pericarditis. A 3-year-old male, Caucasian, was born to consanguineous healthy parents. At the age of 11 months, he presented daily fever (temperature >40 °C), irritability, hepatomegaly, splenomegaly; and tender and itching, erythematous papular and edematous plaque lesions. Echocardiogram showed mild pericarditis. Skin biopsy revealed a neutrophil infiltrate without vasculitis suggesting Sweet syndrome. Mutational screening of PSMB8 gene revealed homozygous c.280G>C, p.A94P mutation. He responded partially to high doses of oral glucorticoid and intravenous methylprednisolone. Colchicine, azathioprine, methotrexate, cyclosporine, and intravenous immunoglobulin were not efficacious. At the age of 3 years and 1 month, tocilizumab was administered resulting in remission of daily fever and irritability. However, there was no improvement of the skin tenderness and itching lesions.

CONCLUSION

A new mutation in a CANDLE syndrome patient was reported with pericarditis and mimicking Sweet syndrome. The disease manifestations were refractory to immunosuppressive agents and partially responsive to tocilizumab therapy.

WHAT IS KNOWN

• Proteasome-associated autoinflammatory syndromes (PRAAS) include four rare diseases. • Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome was seldom reported. What is New: • We described a Brazilian patient with CANDLE syndrome possessing a novel mutation in the PSMB8 gene. • This patient had multiple visceral inflammatory involvements, including rare manifestations, such as pericarditis and mimicking Sweet syndrome.