Allergic contact dermatitis from potassium sorbate and sorbic acid in topical pharmaceuticals and medical devices.

BACKGROUND: The preservatives sorbic acid (SA) and potassium sorbate (PS) are considered rare skin sensitizers. PS-containing products always contain SA to a certain extent, and positivity to PS may reflect sensitization to SA. Their optimal patch-test conditions are unknown. OBJECTIVES: To report on the outcome of testing with SA and PS in various concentrations and/or vehicles. PATIENTS AND METHODS: Seventeen patients with allergic contact dermatitis from PS/SA-containing topical pharmaceuticals and medical devices were patch tested to SA 2% and 5% pet.; SA 1%, 2%, 3%, 5%. eth.; and/or SA 2% aq., whereas PS was patch tested 5% pet. and/or 5% aq. RESULTS: Only one patient, not tested to the ethanol preparations, presented with a (doubtful) positive reaction to SA 2% pet., while this remained negative in 13 patients who reacted to SA 2% eth. The preparations containing SA 5% pet.; 1%, 3%, and 5% eth.; and SA 2% aq. had little or no additional value. PS 5% pet. performed better than 5% aq., and always mirrored SA sensitization. CONCLUSIONS: Sensitization to SA and PS is probably underestimated. SA 2% eth. and PS 5% pet. are preferred for patch testing, and patients sensitized to SA should avoid PS-containing products. HIGHLIGHTS: Potassium sorbate (PS) and sorbic acid (SA) are widely used preservatives. PS-containing products always contain some SA. Both are considered rare skin sensitizers, but contact allergy in response to them might be underestimated. SA 2% eth. and PS 5% pet., rather than SA 2% pet. and PS 5% aq., respectively, may be required to diagnose contact allergy from PS/SA-containing topical pharmaceuticals and medical devices. A positive patch test to PS reflects sensitization to SA, and patients sensitized to SA should also avoid PS-containing products.

The dramatic increase in the rate of methylisothiazolinone contact allergy in Belgium: a multicentre study.

BACKGROUND: The rate of contact allergy and allergic contact dermatitis caused by methylisothiazolinone (MI) is dramatically increasing throughout Europe. OBJECTIVES: To report on methylchloroisothiazolinone (MCI)/MI and MI allergy in Belgium. PATIENTS AND METHODS: Between January 2010 and December 2012, the medical charts of 6599 patients of the Belgian Contact and Environmental Dermatitis Group were retrospectively reviewed for MCI/MI and MI sensitization by use of a standardized questionnaire. Available data on sensitization in 2081 patients tested in 2013 were also included. RESULTS: In 2012, the sensitization rate for MCI/MI had increased to 4.5% and that for MI to 6.0%; the latter showed a further increase to 7.2% in 2013. The people mainly affected were women with a median age of 49 years with hand and/or facial dermatitis, most often resulting from the use of cosmetics. Simultaneous reactions to octylisothiazolinone were observed. CONCLUSION: A dramatic increase in the rate of contact allergy caused by MI in cosmetics is occurring in Belgium. Notwithstanding the recent recommendation to discontinue the use of MI in leave-on cosmetics, safer use concentrations should also be determined for rinse-off products. Close monitoring of MI sensitization in the near future will be necessary, and the highest test concentrations reported for MI and MCI/MI should be included in the baseline series.

Occupational airborne contact dermatitis from benzodiazepines and other drugs.

BACKGROUND: Healthcare workers (or relatives) crushing drug tablets for patients with difficulties in swallowing are at risk of developing sensitization via airborne exposure. Tetrazepam, in particular, is increasingly being described as an important occupational allergen in this regard, although other drugs are also involved. OBJECTIVES: To identify the allergenic culprits in 4 patients, namely 2 nurses, 1 pharmacy assistant, and 1 spouse, who all regularly crushed tablets of systemic drugs and presented with severe airborne dermatitis. METHODS: The patients were patch tested with all of the drugs that they handled, as well as with potential cross-sensitizing molecules. RESULTS: All 4 patients reacted to tetrazepam and other benzodiazepines, some of which they had not previously come into contact with, which favours cross-reactivity rather than concomitant sensitization. These patients also had positive reactions to several other non-structurally related drugs for which, in some cases, there was no history of exposure. CONCLUSIONS: Subjects having to crush drugs, in either an occupational or a non-occupational context, and who present with dermatitis suspected of being airborne-induced, should be patch tested with all contacted medicaments, as well as with possible cross-reacting molecules. Prevention by the use of crushing devices and protective measures (gloves and masks) when medications are handled should be advised.

Methylisothiazolinone, an emerging allergen in cosmetics?

BACKGROUND: A few cases on primary sensitization by, and occupational contact dermatitis from, methylisothiazolinone in paints and glues have been published. In cosmetics, methylisothiazoline (MI) is permitted in a concentration of 100 p.p.m., while 15 p.p.m. for the mixture of methylchloroisothiazolinone and methylisothiazoline (MCI/MI). OBJECTIVES: To present cases of sensitization to, and allergic contact dermatitis from, cosmetic products containing methylisothiazolinone only. PATIENTS, MATERIALS, AND METHODS: Seven patients with suspected contact dermatitis - six of them with (peri-)anal lesions and one with facial dermatitis - were patch tested with the baseline series, the own products exposed to, cosmetic ingredients, as well as with methylisothiazolinone 1000 p.p.m. and MCI/MI 200 p.p.m. RESULTS: The patients with anal lesions had become sensitized by wipes for intimate hygiene, and one patient with facial dermatitis by a make-up remover, all containing methylisothiazolinone only. Three out of seven cases would have been missed if only MCI/MI 100 p.p.m., as present in the baseline series, had been tested. CONCLUSION: The inclusion of methylisothiazolinone as a preservative in cosmetics might not represent the solution to the problem of allergic contact dermatitis from isothiazolinones, since it leads to primary sensitization.

Occupational allergic contact dermatitis from tetrazepam in nurses.

BACKGROUND: Tetrazepam is a muscle relaxant belonging to the benzodiazepine group. Drug eruptions following ingestion of tetrazepam tablets are well known. OBJECTIVE: To draw the attention to occupational airborne dermatitis and/or hand dermatitis in nurses resulting from crushing of tablets for elderly or disabled people. METHODS: Since 2003, 16 nurses with facial (eyelid) and/or hand dermatitis, suspected to be of occupational origin, were patch tested with the medication they handled during work. RESULTS: Ten nurses presented with a positive patch test reaction to tablets containing tetrazepam, 14 controls remaining negative. Some of them also reacted to other drugs. CONCLUSION: Occupational airborne and/or hand contact dermatitis from tetrazepam might be much more common than suspected by dermatologists, particularly in view of the short period in which all cases have been observed.

Transfusion-induced serum sickness.

BACKGROUND: Transfusion-induced serum sickness reactions are rarely reported in the literature. The Type III hypersensitivity reaction to heterologous proteins involves deposition of complement and immune complexes in small vessel walls resulting in a leukocytoclastic vasculitis. A case of a multiply transfused patient with several episodes of serum sickness reactions is presented. CASE REPORT: A 61-year-old man with myelodysplastic syndrome type refractory anemia presented with fever, rash, and polyarthralgia 5 days after transfusion of red blood cells (RBCs). By transfusing plasma-free "washed" RBCs, similar serum sickness reactions were avoided. RESULTS: Laboratory investigation showed an increase of serum creatinine, hematuria, and proteinuria. Levels of circulating immune complexes immunoglobulin G and immunoglobulin M were increased. Hypocomplementemia could not be demonstrated. Histopathologic examination of the skin showed leukocytoclastic vasculitis, compatible with serum sickness. CONCLUSION: The importance of early recognition of transfusion-induced serum sickness reactions is emphasized, because this can reduce unnecessary morbidity from this unusual complication of transfusion. To prevent this type of transfusion reaction, patients who experienced serum sickness-like reactions after transfusion should only receive plasma-free washed RBCs.

Allergic contact dermatitis to DMDI in an office application.

Contact dermatitis to isocyanates is a problem and is usually described within industrial settings. A patient who developed an acute allergic contact dermatitis using a dicyclohexylmethane-4,4'-diisocyanate (DMDI)-charged cartridge to create resin-coated '3D labels' within an office environment is described.