[Nickel allergy and orthodontics]. / Nikkelallergie en orthodontie.

Nickel hypersensitivity is a common problem, especially among young females, with a prevalence of 5 to 10%, increasing to 30%. In comparison with the oral mucosa, skin is more sensitive to an allergic reaction. The oral mucosa is less sensitive to nickel due to the difference in anatomical structure and the presence of pellicle. Nickel is used in many orthodontic appliances. Due to corrosion nickel ions can be released into the oral cavity. The extent of the corrosion of the appliance depends on the pH, the composition of saliva and plaque, temperature and mechanical loading. In spite of the relatively high amount of nickel processed in orthodontic appliances nickel allergies are rare. In cases of nickel-hypersensitivity, nickel-free appliances should be used.

[Latex glove allergy in dental practice]. / Allergie voor latexhandschoenen in de tandartspraktijk.

Skin reactions due to the use of latex examination gloves occur frequently in dental practice. They consist of immediate type I allergy to natural latex protein, type IV delayed hypersensitivity to rubber additives and irritant dermatitis. Type I allergy to latex protein can cause contact urticaria, angioedema, rhinoconjunctivitis and asthma in the dentist, the dental assistant and also in the patient. Exceptionally, latex allergy can cause a life-threatening anaphylactic reaction. Cross reactions to tropical fruit can occur in the latex allergic patient. Type IV allergy causes allergic contact dermatitis. Rubber additives are also present in synthetic rubber. Glove advice for latex allergic patients are presented.

Methyldibromoglutaronitrile is an important contact allergen in The Netherlands.

From 15 May to 15 December 1994, 2943 patients suspected of having contact dermatitis (1955 women, 988 men) were patch tested with methyldibromoglutaronitrile 0.3%, 0.1% and 0.05% pet. 119 patients (4.0%; women 4.1%, men 3.8%) proved to be allergic. 71% of the reactions were considered to be relevant. In 2/3 of the patients, causative products were cosmetics, in 1/3 moistened toilet tissues. Testing with methyldibromoglutaronitrile at lower concentrations (0.05% and 0.1%) and with commercial allergens (Euxyl K 400 and methyldibromoglutaronitrile, both containing methyldibromoglutaronitrile 0.1%), resulted in a number of false-negative reactions. All preservatives in the European standard series had lower scores than the 4% positive reactions to methyldibromoglutaronitrile (formaldehyde 2.0%, MCI/MI (Kathon CG) 3.2%, parabens 1.0%, quaternium-15 1.3%). It is concluded that methyldibromoglutaronitrile (present in the commercial preservative Euxyl K 400) is an important contact allergen in the Netherlands in cosmetics and moistened toilet tissues. It should be added to cosmetics series and to proctological series. The optimal test concentration is unknow, but may be 0.3% pet. The concentration of 0.1% methyldibromoglutaronitrile in the currently available commercial allergens appears to be too low, resulting in a number of false-negative reactions.

Cross-reaction pattern of the cationic emulsifier oleamidopropyl dimethylamine.

13 patients allergic to the cationic emulsifier oleamidopropyl dimethylamine were tested with a series of related amide-amine type surfactants in order to investigate its cross-reaction pattern. With 1 exception, all patients reacted to at least 4 of the test materials. Most reactions were observed to ricinoleamidopropyl dimethylamine lactate and tallowamidopropyl dimethylamine (11 patients, 85%); 9 patients (of 12 tested, 75%) reacted to lauramidopropyl dimethylamine and 6 (46%) to myristamidopropyl dimethylamine. A certain pattern of cross-reactivity was recognised.

The allergens in cosmetics.

The ingredients responsible for allergy to cosmetics were determined in 119 patients suffering from cosmetic-related contact dermatitis. Most reactions (56.3%) were caused by skin care products, followed by nail cosmetics (13.4%), perfumes (8.4%), and hair cosmetics (5.9%). Preservatives were most frequently implicated (32.0%), followed by fragrances (26.5%) and emulsifiers (14.3%). By far the most important cosmetic allergen was Kathon CG, (a preservative system containing, as active ingredients, a mixture of methylisothiazolinone and methyl chloroisothiazolinone) reacting in 33 patients (27.7%). Other frequent causes of cosmetic-related contact allergic reactions were toluenesulfonamide/formaldehyde resin in nail hardener and/or nail lacquer (15 patients [12.6%]), and oleamidopropyl dimethylamine, an emulsifier in baby body lotion (13 patients [10.9%]).

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.

Contact allergy to 4-isopropyl-dibenzoylmethane and 3-(4'-methylbenzylidene) camphor in the sunscreen Eusolex 8021.

10 cases of contact allergy from the sunscreen Eusolex 8021 are reported. 5 patients were sensitized to a lipstick, 4 to a sunscreen cream, and 1 reacted to several cosmetic creams. Of 9 patients tested with the 2 ingredients of Eusolex 8021, 5 proved to be allergic to both (chemically unrelated) constituents: 4-isopropyl-dibenzoylmethane and 3-(4'-methylbenzylidene) camphor; 4 were allergic to 4-isopropyl-dibenzoylmethane only. Contact allergy to this recently introduced broad spectrum sunscreen may not be rare. The relevant literature is reviewed.

Contact allergy to preservatives--II.

To determine whether the prevalence of allergic reactions to certain preservatives warrants their inclusion in a routine series for patch testing, a tray of 14 preservatives was tested in 501 consecutive suspected contact dermatitis patients. More than 1% positive reactions were found with DMDM hydantoin, Kathon CG, and alkyl trimethyl ammonium chloride only. The concentration of alkyl trimethyl ammonium chloride (0.1% aqua) was considered too high. Of 6 patients reacting to the formaldehyde releaser DMDM hydantoin, 4 were positive to formaldehyde. Kathon CG may be an important allergen in the Netherlands, and it is worthwhile for dermatologists there to add it to the standard test series. The recent inclusion of quaternium-15 in the ICDRG standard series appears to be of little value to them.

[Elasticity of the skin in chronic venous insufficiency]. / Etude de l'élasticité de la peau dans l'insuffisance veineuse chronique.

The results of our measurements of skin elasticity at the level of the calf, show that the existence of a cutaneous pump is unlikely. In addition, they are not consistent with the suggestion that the skin acts as an elastic stocking. In case of chronic venous insufficiency (CVI), the loss of elasticity which is demonstrated, is probably secondary to a persisting dermal edema. In patients with essential varicosities, a significant loss of elasticity is only noted in case of reticular varicosities. Essential truncular varicosities are not accompanied with a significant loss of elasticity. It is therefore highly likely that truncular varicosities and reticular varicosities do not have the same etiology.