Faculty Bibliography

BACKGROUND:Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) allergy has increased for the last decade, mostly not only because of high concentrations in cosmetics but also because of its use as a biocide in industrial settings. OBJECTIVE:We report an outbreak of allergic contact dermatitis in 8 workers at a water bottling plant secondary to excess levels of MCI/MI in the cooling system, found to be at levels 5 times the manufacturer's recommendations. METHODS:Of 15 workers in the plastic bottle manufacturing area, 8 developed dermatitis, and 4 were referred for patch testing using a 100-allergen panel applied and interpreted in the standardized method according to the North American Contact Dermatitis Group. RESULTS:Four workers had a positive reaction to MCI/MI. An investigation at the plant revealed that the concentration of MCI/MI was 365 ppm. The manufacturer's recommended level was 48 ppm. The cooling system was subsequently flushed, and biocide levels decreased to recommended levels. Afterward, all the affected workers experienced clearance of their allergic contact dermatitis. CONCLUSIONS:Occupational sensitization to MCI/MI is on the rise, in this instance, because of excess levels in the cooling system. Our findings demonstrate the continued need for awareness of the allergenicity of this preservative in the occupational setting.

BACKGROUND:SOX10 immunostaining has been considered a highly sensitive and specific marker for melanoma. But there is evidence suggesting that SOX10 positive cells can be present in dermal scars. Therefore, we investigated whether non-melanocytic cell types present in chronic inflammatory processes or benign lymph nodes express SOX10. METHODS:We retrospectively selected 20 benign lymph nodes and 20 cutaneous granulomatous dermatoses. SOX10, CD68, and Melan-A immunohistochemistry was performed in all cases. RESULTS:Scattered SOX10 positivity was found in 85% of lymph nodes, specifically in subcapsular and medullary sinuses and in 85% of granulomatous dermatoses. In granulomatous dermatoses, the Melan-A stain did not label the scattered SOX10 positive cells and it was difficult to determine if CD68 was co-expressed on the SOX10 positive cells. In the lymph nodes, the SOX10 positive cells did not co-express Melan-A or CD68. CONCLUSIONS:We report SOX10 positive cells detected in granulomatous dermatoses and benign lymph nodes. In lymph nodes, SOX10 positive cells were exclusively in subcapsular and medullary sinuses. Therefore, SOX10 is an excellent stain for evaluation of metastatic melanoma with the caveat that positivity in subcapsular and medullary sinuses can be of non-melanocytic origin; the use of additional melanocytic markers is recommended in this situations.

Nonmelanoma skin cancers, typically induced by ultraviolet light, are rarely found on the palmar aspects of the hands. Here, we describe a case of a basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) collision tumor on the palm of a 71-year-old woman. A brief review of literature regarding basal cell carcinoma of the palm and hand are provided, including etiology, diagnosis, and treatment recommendations.

Poison ivy, poison oak, and poison sumac are the most common causes of clinically diagnosed allergic contact dermatitis in North America. Approximately 50% to 75% of the US adult population is clinically sensitive to poison ivy, oak, and sumac. We reviewed the botany and history of these plants; urushiol chemistry and pathophysiology, clinical features, and the prevalence of allergic contact dermatitis caused by these plants; and current postexposure treatment and preventive methods, including ongoing investigations in the development of a vaccine (immunotherapy). Although extensive efforts have been made to develop therapies that prevent and treat contact dermatitis to these plants, there lacks an entirely effective method, besides complete avoidance. There is a need for a better therapy to definitively prevent allergic contact dermatitis to these plants.