Epidemiological, Clinical, and Allergic Profile of Psoriatic Patients. Evaluation of the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC). / Perfil epidemiológico, clínico y alérgico en pacientes con psoriasis. Evaluación del Registro Español de Dermatitis de Contacto (REIDAC).

BACKGROUND: Psoriasis is a chronic inflammatory dermatosis whose clinical and topographic distribution requires differential diagnosis, or the possible association with allergic contact dermatitis (ACD), requiring patch testing (PT) as part of the diagnostic procedure. OBJECTIVES: To describe the epidemiological, clinical, and allergic profile of patients with a primary or secondary diagnosis of psoriasis undergoing PT and compare them with patients with a diagnosis of ACD at the end of the diagnostic process. METHODS: Cross-sectional study with data from REIDAC from 2018 through 2023 of selected patients with a diagnosis of psoriasis and/or ACD. RESULTS: A total of 11 502 patients were included, 513 of whom had been diagnosed with primary or secondary psoriasis, 3640 with ACD, and 108 with both diseases. Men were more predominant in the groups of patients with psoriasis, psoriasis+ACD, and lesions were more predominantly seen in the hands with little association with atopic factors vs the ACD group. The rate of positivity in PT to the 2022 Spanish battery of allergens was lower in the group with psoriasis only in 27% of the patients. The most common allergens found in the psoriasis group were also the most common ones found in the overall ACD population. CONCLUSIONS: Overall, 36.2% of psoriatic patients tested positive in PT to the 2022 Spanish battery of allergens, which proved that this association is not uncommon. Overall, psoriatic patients had a higher mean age, were more predominantly men, and showed more hand involvement.

Allergic contact dermatitis due to nickel: descriptive study in a tertiary hospital, 2000-2010.

OBJECTIVE: The aim of this study based on the records of the dermatology department of a tertiary referral hospital was to describe patients treated for allergic contact dermatitis induced by nickel between 2000 and 2010. MATERIALS AND METHODS: From records of the skin allergy section of the dermatology department we extracted and analyzed information for patients who underwent patch testing with the standard series of the Spanish Contact Dermatitis Research Group (GEIDAC), which includes a patch with 5% nickel sulfate in petroleum jelly. The possibility that nickel release from various objects might have triggered the patient's dermatitis was assessed with the dimethylglyoxime spot test, which reveals a reddish precipitate if the metal is present. RESULTS: A total of 3,404 patients underwent GEIDAC patch testing during the study period; 24.2% had positive reactions to the patch containing 5% nickel sulfate in petroleum jelly. However, the contact dermatitis could be attributed to nickel in only 57 of the 824 patients (6.9%) who showed sensitization to nickel. CONCLUSIONS: Patch-test evidence of sensitization was found to be clinically relevant in only a small percentage of patients. We emphasize the usefulness of the dimethylglyoxime test to help establish the relevance of a positive nickel patch test. This test is even useful for identifying the specific object responsible for a patient's dermatitis.

Is p-Phenylenediamine Still a Prevalent Contact Allergen in Spain? / ¿Sigue siendo la parafenilendiamina un alérgeno de contacto prevalente en España?

OBJECTIVES: To analyze trends in the prevalence of contact sensitization to p-phenylenediamine between 2004 and 2014, taking into consideration that the concentration of this product in cosmetics was regulated in 2009. To explore risk factors for contact allergy to p-phenylenediamine. MATERIAL AND METHODS: Retrospective observational study of patients suspected of having contact dermatitis from allergy to p-phenylenediamine during the years between 2004 and 2015 in 8 tertiary level hospitals. The patients underwent patch testing (TRUE-test) with the standard series of the Spanish Research Group on Contact Dermatitis and Skin Allergies. This series included p-phenylenediamine 1%. We followed international recommendations for the statistical analysis of data related to contact allergies. RESULTS: Three hundred eighty-six out of 9341 patients (4.1%) had positive reactions to p-phenylenediamine. The prevalence tended to decrease in the early years (2004-2007) and then leveled off at around 4%. Risk factors for developing contact dermatitis from p-phenylenediamine were sex, age over 40 years, multiple sensitivities, and profession, notably workers in hair salons and those who handle rubber and plastics. CONCLUSIONS: The prevalence of p-phenylenediamine allergy remains high among patients with contact eczema. Risk factors for p-phenylenediamine contact allergy are consistent with previous reports.