Cutaneous delayed-type hypersensitivity in patients with atopic dermatitis: reactivity to topical preservatives.

BACKGROUND: Patients with atopic dermatitis (AD) have chronic dry skin to which they frequently apply skin care products containing preservatives, and they are predisposed to developing cutaneous delayed-type hypersensitivity. OBJECTIVE: We sought to compare the rates of positive patch test reactions to allergens on the North American Contact Dermatitis Group (NACDG) standard tray among patients with and without AD and to assess whether atopic patients in our database were more likely to patch test positive to preservatives. METHODS: A total of 2453 patients underwent patch testing to the NACDG standard screening series. The incidence of positive patch test reaction among patients with AD (n = 342) and without AD (n = 2111) was assessed. Statistical analysis was done using a χ(2) test. RESULTS: Compared with nonatopic patients, patients with AD were statistically more likely to have positive patch tests. AD was associated with contact hypersensitivity to quaternium-15, imidazolidinyl urea, DMDM hydantoin, and 2-bromo-2-nitropropane-1,3-diol but not to parabens, formaldehyde, or diazolidinyl urea. LIMITATIONS: Only patients suspected of having allergic contact dermatitis were tested. Our population was geographically limited to metropolitan Kansas City, MO, and metropolitan New York City, NY. CONCLUSIONS: Patients with AD should avoid the use of skin care products preserved with formaldehyde releasers.

Preparation of polyclonal antibodies to a derivative of 1-aminohydantoin (AHD) and development of an indirect competitive ELISA for the detection of nitrofurantoin residue in water.

Nitrofurans are used widely to treat animal diseases and were identified as the major compounds in many worldwide drug residue violations. To develop a rapid and convenient detection method to measure the residue of nitrofurantoin, we designed an immunogen and prepared a polyclonal antibody to develop an immunoassay in this study. The antibodies obtained were characterized by an indirect cELISA method and showed excellent specificity and sensitivity with IC50 of 3.2 ppb and no cross-reaction with most related species and compounds. Considering that nitrofurans often are used illegally to feed animals through drinking water, we measured the residue of nitrofurantoin in water spiked by the drug. The recovery rates are in the ranges of 88-103% for interassay and 90-103% for intra-assay. The CVs are in the ranges of 3.1-11.4% for interassay and 2.7-6.2% for intra-assay. The detection limit was determined to be 0.2 ppb. The immunoassay developed in this study is suitable to be used as a screening method to detect residues of nitrofurantoin in drinking water for animals.

Patch test reactivity to DMDM hydantoin. Relationship to formaldehyde allergy.

The relationship between contact allergy to formaldehyde and positive patch test reactions to DMDM hydantoin was investigated. 35 formaldehyde-allergic patients were patch tested with serial dilutions of formaldehyde (0.1%-0.3%-1.0% aq.) and DM hydantoin (the non-formaldehyde-containing parent compound of DMDM hydantoin). 21 were also patch tested with MDM hydantoin (1 molecule formaldehyde) in serial dilutions: 7 (33%) reacted to 1 or more concentrations. The other 14 were also tested with DMDM hydantoin (2 molecules formaldehyde) in serial dilutions: 8 (57%) reacted to 1 or more concentrations. Patients patch-test-positive to formaldehyde 0.1% and/or 0.3% tended to show more patch test reactivity to (D)MDM hydantoin than those who reacted only to 1%. Aqueous solutions of (D)MDM hydantoin in concentrations as used in cosmetic products therefore contain enough free formaldehyde to cause dermatitis in a patch test system in some formaldehyde-allergic patients: 12 such patients applied a cream containing 1% DMDM hydantoin to the flexor aspect of the lower arm twice daily for 1 week; 4 (33%) developed dermatitis. The use of a cream containing 0.25% DMDM hydantoin in these 4 patients still caused dermatitis in 1 and provoked itching in another. An increase in the use of DMDM hydantoin in cosmetic products will also inevitable increase the risk of cosmetic dermatitis in consumers allergic to formaldehyde.

IgA deficiency, epilepsy, and hydantoin medication.

Serum-immunoglobulin concentrations were measured in 364 patients with epilepsy. On dividing the patients into those treated with or without hydantoins, and according to possible aetiological factors, a characteristic pattern emerged. Irrespective of the treatment given, the mean values of IgA were significantly reduced in patients in whom constitutional factors were apparent, including those with familial prevalence of seizures. While IgA was rarely found below 0-6 mg/ml, a limit chosen to define IgA deficiency in patients not treated with hydantoins, the IgA level was subnormal in 20-25% of the patients treated with such drugs. In contrast, the mean concentration of IgA was normal and no individual subnormal values were observed in epileptic patients treated with or without hydantoins whose disease was thought to be secondary to traumatic or infectious events or to metabolic disturbances. The data suggest that epilepsy with constitutional characteristics might predispose to low IgA, but that IgA deficiency only occurs when hydantoins are given. Whether this postulated predisposition is relevant to the aetiology or pathogenesis of epilepsy remained unresolved.