ABSTRACT
BACKGROUND: Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and methylisothiazolinone (MI) contact allergies are rising dramatically. Moreover, 100 ppm of MCI/MI patch test might not detect an important number of MCI/MI and MI allergies. OBJECTIVES: This study aimed to present the prevalence of contact allergy to both preservatives in an area of Spain and to investigate if 100 ppm of MCI/MI is an adequate concentration for a proper diagnosis. METHODS: A prospective study was conducted from October 2011 to September 2013. All patients were patch tested with the Spanish baseline series (containing 100 ppm of MCI/MI) and with 200 ppm of MCI/MI and 2000 ppm of MI. RESULTS: A total of 490 patients were patch tested. The MCI/MI prevalence was 10% and increased from 7.8% in last term of 2011 to 14.3% in the first 9 months of 2013. The MI prevalence was 4.5% and increased from 1% to 7.7% in the same period. One hundred parts per million of MCI/MI could not diagnose 24.5% of MCI/MI allergies. All MI allergies were detected by 200 ppm of MCI/MI, whereas only 68.2% were positive to 100-ppm concentration. CONCLUSIONS: For a correct diagnosis of MCI/MI and MI contact allergies, we advocate increasing the MCI/MI patch test concentration to 200 ppm along with a temporal inclusion of MI in the North American Contact Dermatitis Group baseline series.
Subject(s)
Dermatitis, Occupational/diagnosis , Thiazoles/adverse effects , Adult , Causality , Cosmetics/adverse effects , Dermatitis, Allergic Contact/diagnosis , Dermatitis, Allergic Contact/epidemiology , Dermatitis, Allergic Contact/etiology , Dermatitis, Occupational/epidemiology , Dermatitis, Occupational/etiology , Female , Humans , Male , Middle Aged , Patch Tests/statistics & numerical data , Preservatives, Pharmaceutical/adverse effects , Prevalence , Prospective Studies , Spain , Young AdultABSTRACT
A 78-year-old woman diagnosed with rheumatoid arthritis without a history of skin tumors or immunosuppressive medication, started treatment with leflunomide. One month after the introduction of the drug, and for two consecutive years, she developed multiple crateriform nodules and papules on her lower extremities . Biopsy specimens showed keratoacanthomas and squamous-cell carcinomas. Owing to suspicion that the drug could be implicated in the appearance of these tumors, the patient decided to suspend the drug. No new skin lesions have appeared in seventeen months of clinical follow-up. There have been several published case reports of multiple keratoacanthomas associated with immunosuppressive therapy such as sorafenib and imiquimod. However, we found no mention in the literature of the eruption of multiple keratoacanthomas in patients with rheumatoid arthritis treated with leflunomide. We suggest, that the the sudden appearance of skin tumors in our patient is related to the introduction of leflunomide, but additional case reports are required to confirm this association.
