Allergology in dermatology

Lucie Van Esbeen (1), Anne Herman (2) Published in the journal : October 2024 Category : Peause dermatologique

In this article, we report on the “PEAU’se dermatologique” meeting held at the Cliniques universitaires Saint-Luc, dedicated to allergic contact dermatitis (ACD). Professor Anne Herman reminded us of the main contact allergens involved, depending on skin location.

ACD, which affects approximately 25% of the general population, is an acquired immunological disorder resulting from exposure to sensitizing substances (contact allergens) in previously exposed and sensitized individuals. The article describes the various allergological tests available, in particular patch tests, repeated open application test (ROAT), and glove repeated application test (GRAT), specifying their indications and procedures.

The article reviews different clinical topographies frequently encountered in consultations (eczema of the hands, feet, eyelids, and lips) and identifies the most frequently implicated allergens for each. The specificities of ACD in children are also discussed, as well as the emergence of new allergens.

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Spitzoid lesions – Reminders and novelties in dermoscopy and anatomopathology

Nina Nielens, MD.1, Pascal Van Eeckhout, MD.2, Pauline Richez, MD.3, Liliane Marot, MD.1-2 Published in the journal : December 2021 Category : Peause dermatologique

Spitzoid lesions represent a dermoscopic and anatomopathological challenge. While the spitzoid phenotype is easily recognizable, the differential diagnosis between Spitz nevus, atypical Spitz tumor, and spitzoid melanoma is difficult, requiring the integration of clinical, dermoscopic, histological, and molecular biological criteria.

Three main dermoscopic patterns define the Spitz nevus without asserting its benignity: the starburst pattern, the globular pattern and the vascular pattern. Symmetrical distribution of colors and structures, nodularity, ulcerations, shiny white streak, and age (>/≤ 12 years) must also be taken into account before deciding whether to reassure these patients, monitor the lesions or excise them. Based on these criteria, the International Society of Dermoscopy proposed a management algorithm (Figure 4).

Histologically, the Spitz nevus is composed of multiple epithelioid cells with nucleated nucleoli packed within hyperplastic epidermis. The following criteria must be integrated to enable the histological differential diagnosis between typical or atypical spitzoid tumors, including symmetrical distribution of structures, patient’s age, lesion diameter, infiltration of subcutaneous tissue, ulceration, mitotic index, and presence of genetic alterations.

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