New insights into pustular dermatoses in pediatric patients

Neutrophil extracellular traps and neutrophilic dermatosis: an update review

Neutrophils have both antimicrobial ability and pathogenic effect in the immune system, neutrophil extracellular traps (NETs) formation is one of the representative behaviors of their dual role. NETs formation was triggered by pathogen-related components and pathogen non-related proteins as cytokines to exert its effector functions. Recent studies indicate that the pathogenicity of NETs contributed to several skin diseases such as psoriasis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and neutrophilic dermatosis. Especially in neutrophilic dermatosis, a heterogeneous group of inflammatory skin disorders characterized with sterile neutrophilic infiltrate on dermis, NETs formation was reported as the way of participation of neutrophils in the pathogenesis of these diseases. In this review, we describe the different processes of NETs formation, then summarized the most recent updates about the pathogenesis of neutrophilic dermatosis and the participation of NETs, including pyoderma gangrenosum and PAPA syndrome, Behçet syndrome, hidradenitis suppurativa, Sweet Syndrome, pustular dermatosis and other neutrophilic dermatosis. Furthermore, we discuss the link between NETs formation and the development of neutrophilic dermatosis.

Acute generalized exanthematous pustulosis in children and adolescents in Singapore: A ten-year retrospective review

BACKGROUND

Acute generalized exanthematous pustulosis (AGEP) is a rare, severe, cutaneous adverse reaction. Although most commonly caused by drugs, it can also be triggered by infections, especially in children.

METHODS

This is a retrospective study involving children and adolescents aged 16 years or younger, diagnosed with AGEP between January 2010 and March 2020 in our tertiary pediatric hospital. Information pertaining to the patient's demographics, clinical presentation and progress, biochemical, microbiological, and histopathological investigations, treatment, and outcomes was analyzed.

RESULTS

Eight patients were diagnosed with AGEP with mean age 8.2 years (range: 1.7-16.0 years). None of the patients had a personal or family history of psoriasis. Almost all patients had fever (n = 7, 87.5%). Although all 8 patients had intercurrent illness, 5 cases were attributed to infection, while the other 3 were likely precipitated by drugs. Abnormal hematological and biochemical parameters included a raised absolute neutrophil count (mean: 11.5 × 10⁹ /L, range: 5.0-30.9 × 10⁹ /L), C-reactive protein (mean: 52.5 mg/L, range: 5.0-143.7 mg/L), and erythrocyte sedimentation rate (mean: 38.6 mm/h, range: 6-64 mm/h). All patients developed post-pustular desquamation and subsequently recovered. The mean duration from onset to cessation of acute pustulation was 5.6 days (range: 3.0-10.0 days). One patient developed a recurrent episode of AGEP.

CONCLUSION

AGEP is rare and may be more commonly caused by infections in children. The condition is self-limiting with overall good outcomes in this age-group. In cases with concomitant infection and drug use, formal allergy testing should be arranged after resolution of the infection to confirm the underlying etiology.

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

Genetic Testing in Dermatology: A Survey Analyzing Obstacles to Appropriate Care

BACKGROUND/OBJECTIVES

The past several decades have witnessed unprecedented advances in genomic technology, bringing genetic testing to the forefront of medical practice and moving us towards the practice of personalized medicine. Genetic testing has become an important aspect in preempting and successfully treating diseases in dermatology, yet difficulty remains in regards to obtaining genetic testing for patients. We conducted a survey for pediatric dermatologists in order to try to gauge and understand where difficulties lie in obtaining genetic testing and to analyze how best these issues can be resolved.

METHODS

An 18-question survey was emailed to 480 dermatologists who have attended at least one of the last three annual Society for Pediatric Dermatology (SPD) meetings.

RESULTS

Virtually all providers encountered at least one situation in which they required genetic testing for a patient (97.3% [n = 108]) and 37.4% indicated needing genetic testing more than six times per year. Of the respondents who had attempted to obtain genetic testing, half were unsuccessful in obtaining coverage more than 75% of the time (45% [n = 32]) and only 7.0% (n = 5) achieved success 75% to 100% of the time. The most common reasons for obtaining genetic testing included the need to provide an accurate diagnosis, followed by the need to provide prognostic information and appropriate medical management.

CONCLUSION

The role of genetic testing in the practice of dermatology is expanding, yet obtaining coverage for genetic testing remains a challenge. We propose several solutions as to how this can be remedied.

Acute Pustular Dermatosis, Following Topical Treatment With Pimecrolimus, in a Child Affected With Atopic and Contact Hand Dermatitis

Atopic dermatitis is considered an important risk factor for chronic hand dermatitis, which can be seen in children too. Pimecrolimus cream 1% is approved to treat atopic dermatitis in children aged 2 years or older. In adults, this drug has been used for some clinical indications other than atopic dermatitis, such as chronic hand dermatitis. Here, we describe an adverse drug reaction in a 2-year-old child affected with atopic dermatitis, who was treated with topical pimecrolimus in order to ameliorate her concomitant hand dermatitis. The use of topical pimecrolimus led to a previously undescribed hand pustular dermatosis, being consistent with a form of pustular leukocytoclastic vasculitis, which required the permanent discontinuation of topical pimecrolimus.