<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>2795-5001</journal-id>
<journal-title><![CDATA[Portuguese Journal of Dermatology and Venereology]]></journal-title>
<abbrev-journal-title><![CDATA[Port J Dermatol Venereol.]]></abbrev-journal-title>
<issn>2795-5001</issn>
<publisher>
<publisher-name><![CDATA[Permanyer Publications]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2795-50012022000100002</article-id>
<article-id pub-id-type="doi">10.24875/pjd.m22000002</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Histopathological study of allergic contact dermatitis]]></article-title>
<article-title xml:lang="pt"><![CDATA[Estudo histopatológico da dermite de contacto alérgica]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Mendes]]></surname>
<given-names><![CDATA[Rita Bouceiro]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Lobo]]></surname>
<given-names><![CDATA[Marta Aguado]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Lara]]></surname>
<given-names><![CDATA[Pablo Espinosa]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[de Almeida]]></surname>
<given-names><![CDATA[Luís Soares]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
<xref ref-type="aff" rid="Aaf"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Centro Hospitalar e Universitário Lisboa Norte Dermatology Department ]]></institution>
<addr-line><![CDATA[Lisbon ]]></addr-line>
<country>Portugal</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Molecular Medicine Institute, Lisbon Medical School  ]]></institution>
<addr-line><![CDATA[Lisbon ]]></addr-line>
<country>Portugal</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>03</month>
<year>2022</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>03</month>
<year>2022</year>
</pub-date>
<volume>80</volume>
<numero>1</numero>
<fpage>2</fpage>
<lpage>8</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://scielo.pt/scielo.php?script=sci_arttext&amp;pid=S2795-50012022000100002&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.pt/scielo.php?script=sci_abstract&amp;pid=S2795-50012022000100002&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.pt/scielo.php?script=sci_pdf&amp;pid=S2795-50012022000100002&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract  Introduction: Allergic contact dermatitis (ACD) has a wide spectrum of clinical presentations, which mimic diverse dermatological conditions. When patch tests do not identify that the relevant allergens or treatment is not effective, a skin biopsy is warranted. However, there are few descriptive series on the histopathology of ACD. The purpose of this study was to characterize microscopic changes in ACD and to identify features that may help in the differential diagnosis.  Methods: We retrospectively included 20 skin biopsies of ACD cases. Slides were reviewed, and microscopic changes analyzed.  Results: We reported a clinicopathologic concordance of 80%. The main histological differential diagnosis was drug eruption (DE). Common epidermal findings included acanthosis (95%), parakeratosis (85%), and spongiosis (80%). Necrotic keratinocytes were observed in only three cases. The most common dermal change was the presence of a superficial perivascular inflammatory infiltrate. Lymphocytes were present in all cases and eosinophils in 80% of the biopsies, although in much smaller number. Neutrophils and atypical lymphocytes were absent.  Conclusion: In ACD, isolated pathological findings are nonspecific and clinicopathological correlation is essential. Eosinophilic spongiosis is the typical pattern, but findings depend on the stage of evolution. Several histological features (including parakeratosis and epidermal hyperplasia with signs of spongiosis, superficial dermal infiltrate, absence of both apoptotic keratinocytes, and vacuolar degeneration), may aid in the differential diagnosis with DE.]]></p></abstract>
<abstract abstract-type="short" xml:lang="pt"><p><![CDATA[Resumo  Introdução: A dermite de contacto alérgica (DCA) possui um amplo espectro de apresentações clínicas, que podem mimetizar outras patologias. Quando as provas de contato não identificam os alergénios relevantes ou o tratamento se releva ineficaz, deve ser realizada uma biópsia cutânea. No entanto, há poucos estudos descritivos sobre a histopatologia da DCA.  Objetivo: Caracterizar as alterações microscópicas da DCA e identificar características que ajudem no diagnóstico diferencial.  Métodos: Realizámos um estudo retrospetivo que englobou 20 biópsias cutâneas de casos de DCA. As lâminas foram revistas e as alterações microscópicas analisadas.  Resultados: Nas lâminas estudadas, verificou-se uma concordância clínico-patológica de 80% sendo o principal diagnóstico diferencial histológico, toxidermia. Na epiderme, as alterações mais comuns incluíram acantose (95%), paraqueratose (85%) e espongiose (80%). Apenas em 3 casos se identificou necrose de queratinócitos. Na derme, a presença de um infiltrado inflamatório perivascular superficial foi o achado mais frequente. Em todos os casos se observaram linfócitos e, em 80%, eosinófilos. Em nenhuma das lâminas se identificou a presença de neutrófilos ou de linfócitos atípicos.  Conclusão: Na DCA, as alterações histopatológicas são inespecíficas e a correlação com a clínica é essencial. O padrão típico é a espongiose com eosinófilos, mas os achados dependem do tempo de evolução das lesões. Várias características histológicas (incluindo paraqueratose e hiperplasia da epiderme com evidências, ainda que subtis, de espongiose; infiltrado dérmico superficial; ausência de queratinócitos apoptóticos e de degeneração vacuolar) podem auxiliar no diagnóstico diferencial com toxidermias.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Biopsy]]></kwd>
<kwd lng="en"><![CDATA[Dermatitis]]></kwd>
<kwd lng="en"><![CDATA[Allergic contact/diagnosis]]></kwd>
<kwd lng="en"><![CDATA[Allergic contact/pathology]]></kwd>
<kwd lng="pt"><![CDATA[Biopsia]]></kwd>
<kwd lng="pt"><![CDATA[Dermatite alérgica de contato/diagnóstico]]></kwd>
<kwd lng="pt"><![CDATA[Dermatite alérgica de contato/patologia]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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