Hidden contact allergy to formaldehyde in imidazolidinyl urea

Perspectives on formaldehyde toxicity: separating fact from fantasy

Formaldehyde (IUPAC name, methanal) is one of the simplest, most ubiquitous molecules in our environment and troposphere. Exposure to large amounts of formaldehyde can produce a variety of respiratory and dermatologic problems in humans, in both the home and the workplace. However, in spite of anecdotal reports on formaldehyde-induced illness over the past 20 years there is a paucity of data regarding its potential as either an allergen or an antigen in humans. In addition, many of our current impressions about formaldehyde are based on studies of dubious scientific validity. In this review, we discuss the biological and chemical properties of formaldehyde and its presence in materials which we come in contact with, and finally attempt to put in perspective our current understanding of the detrimental effects of formaldehyde on our health, or lack thereof. There is no evidence at present that formaldehyde causes immunological diseases. Finally, and unfortunately, many of the studies have drawn invalid conclusions and are based on poorly controlled anecdotal observations.

Allergic contact dermatitis from formaldehyde. A case study focussing on sources of formaldehyde exposure

Formaldehyde is a common contact allergen. The prognosis of formaldehyde-sensitive patients is generally considered to be bad because of widespread exposure to formaldehyde. 11 patients with eczema and a positive patch test to formaldehyde were interviewed by a dermatologist and a toxicologist/chemist and instructed to fill in a questionnaire on exposure to chemical products. The content of formaldehyde and formaldehyde releasers in such products was examined using the database of the Danish Product Register (PROBAS) and by supplemental inquiries of manufacturers or importers. All the patients used one or more products containing formaldehyde or formaldehyde releasers. Sources of exposure were cosmetics and personal care products, dishwashing liquids, water-based paints, photographic products, etc. Patients were advised to use alternatives to those products containing formaldehyde or formaldehyde releasers. The status of 10 out of the 11 patients' eczema at follow-up was about 1/3 healed, 1/3 improved and in 1/3 no change. When the relevance of positive patch test reactions to formaldehyde was based on information obtained on exposure, a very high rate of current relevance was found. Computerized data on product composition allows the screening of products for contact allergens and also generates lists of contact allergens indicated for patch testing, based on the patients' own products.

Sunscreening agent intolerance: contact and photocontact sensitization and contact urticaria

Reports in the literature of sensitization associated with many commonly used sunscreening agents including p-aminobenzoic acid (PABA), PABA derivatives, anthranilates, salicylates, cinnamates, benzophenones, and dibenzoylmethane derivatives are reviewed. Several of these case reports involved subjects with various photodermatoses, implicating enhanced sensitivity of the patient's skin to both light and chemicals. Despite the widespread use of sunscreens, the small number of published reports of contact and photocontact sensitization to these agents suggests that either such sensitization is less than commonly perceived or is underreported. Establishment of a registry for reporting adverse effects associated with sunscreening agents would help to characterize the incidence of sensitization.

Contact allergy to diazolidinyl urea (Germall II)

4 cases of contact allergy to diazolidinyl urea (Germall II) in a "hypoallergenic" brand of cosmetics are described. 2 patients sensitized by these cosmetics were not allergic to formaldehyde. 2 other patients already sensitive to formaldehyde had exacerbations of dermatitis due to diazolidinyl urea. The following tentative conclusions were drawn. (i) Contact allergy to diazolidinyl urea may or may not be due to formaldehyde sensitivity. (ii) Patients allergic to formaldehyde may suffer contact allergic reactions from the use of cosmetics containing diazolidinyl urea. (iii) Patients sensitized to diazolidinyl urea may cross-react to imidazolidinyl urea and vice-versa. (iv) It is suggested that the sensitizing potential of diazolidinyl urea is greater than that of imidazolidinyl urea. (v) Aq. solutions may be preferable to pet. for patch testing with diazolidinyl urea.