Abstract Background Atopic dermatitis is the most common inflammatory skin disease in childhood and has an important impact on quality of life, especially severe cases or those that are recalcitrant to treatments. Sensitization to allergens with the potential for allergic contact dermatitis is a factor associated with cases of recalcitrant atopic dermatitis. Understanding the relationship between atopic dermatitis, allergens, and allergic contact dermatitis is essential. In Brazil, there are no studies on sensitization to allergens found in patch tests with pediatric batteries in patients with atopic dermatitis. Objectives To verify the main sensitizing agents, the prevalence of allergic contact dermatitis and the epidemiological and clinical profile of children and adolescents with atopic dermatitis. Methods Cross-sectional, prospective study in patients between 4 and 18 years of age, with recalcitrant atopic dermatitis, treated at the Sanitary Dermatology Outpatient Clinic (RS). All patients underwent patch tests with a battery of pediatric allergens. Results The prevalence of sensitization and allergic contact dermatitis in the evaluated patients was 37.07% (20/54) and 27.7% (15/54), respectively. The most frequent allergens were: nickel sulfate (16.7%), disperse blue (5.6%), and fragrance mix I (5.6%). Nickel was associated with the female sex (p = 0.019). Study limitations Sample size and selection, absence of a control group. Conclusions A proportion of patients with recalcitrant atopic dermatitis may be sensitized to different allergens and may even have developed allergic contact dermatitis. Recognizing this context is important in the prevention strategy and management of the disease.

Abstract Background: Despite being widely used in different areas of dermatology, there have been few studies evaluating the benefit of dermoscopy in the interpretation of patch tests, especially in weak and doubtful reactions. Objectives: To evaluate the role of dermoscopy in the interpretation of patch tests and describe the main findings of the reactions. Method: Prospective study, carried out in dermatology reference centers in southern Brazil, which evaluated the final results of patch tests analyzed with the aid of dermoscopy. Results: 77 patients and 160 reactions were included. The most prevalent substances were nickel sulphate (23.8%), kathon CG (9.4%), and perfume mix (8.8%). The main dermoscopic findings were reaction area greater than half of the chamber site (90%), homogeneous erythema (86.9%), vesicles (30%), crusts (21.3%), perifollicular erythema (35%), pore reaction (19.4%) and pustules (8.8%). Dermoscopy was found to facilitate the definition of erythema in reactions on black skin and when due to substances with deposition of pigment. Of the 64 weak or doubtful reactions, 36 (56.25%) showed a change in the final result after dermoscopy evaluation; of the 36 doubtful reactions, 33 (91.6%) showed a change in the final result after dermoscopy evaluation (p < 0.001). Study limitations: The probable limitation of the study is its sample size. Though certain significance levels have been reached, other possible relationships may not have been observed. Conclusion: Dermoscopy improves significantly the interpretation of patch tests, especially in weak and doubtful reactions.

Abstract: Verrucous hemangioma is a rare vascular skin disorder with an immune profile similar to vascular neoplasms, but with behavior and evolution of vascular malformations. Its main differential diagnosis is angiokeratoma circumscriptum neviforme, with an almost indistinguishable clinical presentation because both diseases appear as erythematous patches that evolve to violaceous plaques, becoming scaly and even verrucous, most commonly affecting the lower limbs. Histopathology is crucial for the correct diagnosis: while in angiokeratoma the vascular alterations are limited to the papillary dermis, verrucous hemangioma extends deep into the dermis, reaching the subcutaneous tissue.

Abstract: Pyoderma gangrenosum (PG) is an uncommon neutrophilic dermatosis, with variable clinical features, nonspecific histopathology and multifactorial pathogenesis, posing a challenging diagnosis for the dermatologist. Pyoderma gangrenosum is a diagnosis of exclusion and should be included in the differential diagnoses of the verrucous syndrome. We report a granulomatous variant affecting the face.

Paciente do sexo masculino, 33 anos de idade, foi investigado por apresentar um quadro de dor abdominal em flanco direito, proteinúria, hematúria e níveis elevados de creatinina sérica. A ultrassonografia evidenciou rins de tamanhos assimétricos, e a biópsia renal confirmou o diagnóstico de oligomeganefronia (OMN). OMN é uma forma muito rara de hipoplasia renal, e ainda mais infrequente na faixa etária adulta. Na população pediátrica, OMN culmina com insuficiência renal terminal em poucos anos. Este é o sexto caso de oligomeganefronia de início tardio relatado na literatura, que ainda não teve evolução para insuficiência renal crônica.

A 33-year old caucasian man was investigated for pain in the right flank, proteinuria, hemathuria and an elevated serum creatinine level. He also presented an abnormal ultrasonography, which revealed asymmetric kidneys. Through renal biopsy, the diagnosis of oligomeganephronia (OMN) was confirmed. OMN is a very rare form of renal hypoplasia, and late-onset in adulthood is even rarer. In the pediatric population, OMN leads to end-stage-renal-failure(ESRF) in a few years. This is the sixth case related in the literature of a late-onset OMN who have not yet developed ESRF.