[Testing plant products brought in by patients]. / Comment tester les produits végétaux apportés par le patient.

Plant-induced dermatoses involve a variety of mechanisms and result from direct contact with the plant itself, part of the plant or an extract thereof; they may also involve phototoxic or photoallergic reactions. Subjects most exposed are woodworkers, agricultural workers, orchard workers, gardeners, etc. However, many subjects are also exposed during leisure activities (fishing, country walks, gardening, sports, etc.). History-taking is thus essential before beginning testing in order to establish any differential diagnoses. Tests consist of challenges using commercially available allergens, patch-tests using the plant itself or plant extracts, and skin prick-tests or photopatch-tests.

Thaumetopoein: an urticating protein from the hairs and integument of the pine processionary caterpillar (Thaumetopoea pityocampa Schiff., Lepidoptera, Thaumetopoeidae).

Hairs of the Thaumetopoea pityocampa caterpillar (Lepidoptera) cause a cutaneous reaction in man and animals. The irritating fraction extracted from hairs contains soluble proteins which were separated by various electrophoretic and immunoelectrophoretic techniques. Some of these proteins are present also in cuticle and haemolymph. One protein of 28,000 mol. wt is hair specific and caused a reaction in pig skin identical to that produced by hair extract. It is therefore an urticating protein which we have named thaumetopoein. This protein is formed of two subunits of molecular weights 13,000 and 15,000. It is present in large quantities in the glands producing urticating hairs.

[The oak processionary caterpillar (Thaumetopoea processiona L.) and man: urticating apparatus and mechanism of action]. / La chenille processionnaire du chêne (Thaumetopoea processionea L.) et l'homme: appareil urticant et mode d'action.

The urticating apparatus of the oak processionary caterpillar was studied by electron microscopy at times when this species was exceptionally abundant in France. Proteins of urticating hairs were studied by electrophoresis on acrylamide gel and were compared with thaumetopoein, an urticating protein of the pine processionary caterpillar, using immunological techniques. A thaumetopoein-like protein was found to be present in oak processionary urticating hairs. This protein has a histamine-releasing effect in the guinea-pig. Contact dermatitis caused by the oak processionary caterpillar is described and compared to that produced by the pine processionary caterpillar.

[Acute generalized exanthematous pustulosis in a child and epicutaneous tests with mercurials]. / Pustulose exanthématique aiguë généralisée chez un enfant et tests épicutanés aux mercuriels.

Diffuse exanthema with fever followed by superficial nonfollicular aseptic pustules was observed in an 11-year old boy after conducting a thiomersal epicutaneous test and manipulation of a broken medical thermometer. The patient healed within two days without any treatment. The initial responsibility of mercury and its derivatives, and the primary sensitization and relevance of the epicutaneous tests are discussed. Mercury and its derivatives should be limited as much as possible in medicine and cosmetology.

[Sensitization to cockroach allergens evaluated by skin tests in children with atopic dermatitis]. / Sensibilisation à la blatte évaluée par tests épicutanés dans la dermatite atopique de l'enfant.

INTRODUCTION: Cockroach and house dust mites (Dermatophagoides pteronyssinus, Dp and farinae, Df) are the most often implicated aeroallergens in severe asthma, hay fever and conjunctivitis. Cockroach allergy is still unknown in atopic dermatitis. PATIENTS AND METHOD: 146 children with atopic dermatitis-aged 6 months to 15 years- have been patch tested with the European standard series and some aeroallergens. We have studied the sensitisation to cockroach allergens and compared to Dp and Df. RESULTS: 113 children reacted positively at least to one of the 3 aeroallergens (77 p. 100), 61 children had a positive reaction to cockroach (42 p. 100) and 29 simultaneously to the 3 allergens. DISCUSSION: Delayed hypersensitivity to house dust mites in young children with atopic dermatitis suggests early epicutaneous sensitization due to an altered epidermal barrier. For us, cockroach could also be implicated in some flare-ups of atopic dermatitis. Eviction of cockroach and house dust mite should be proposed for children with a positive patch test to cockroach.

[Cutaneous allergy to epichlorhydrine (author's transl)]. / L'allergie cutanée a l'épichlorhydrine.

Allergies due to epichlorhydrin are seen more and more frequently. This product, which has several uses, is one of the essential components in epoxy resins. The follow-up of six cases has enabled us to determine the optimal concentration to be used in epichlorhydrin epicutaneous tests. Since this product is frequently encountered, it ought to be integrated among the other samples in current skin tests.

[Dermatitis caused by estrogens]. / Dermatite aux oestrogènes.

BACKGROUND: We report a case of sensitization to estrogen. CASE REPORT: A 40-year-old woman consulted for skin disorders which followed a cyclic pattern. At each menses, the patient developed pruritus and erythematous papulovesicular lesions over the members and trunk. Estraderm patch contact dermatitis was evident. Prick and patch tests with alcoholic solutions of estrone alone were positive. Serum tests were positive for anti-ethinyl-estradiol antibodies and anti-progesterone antibodies. DISCUSSION: Autoimmune dermatitis can be caused by sensitization to endogenous or exogenous sex hormones. Clinical manifestations and histological findings are variable and non-specific. The cyclic nature of the manifestations is however quite suggestive. Positive prick and patch tests performed with alcohol solutions of the hormones may give the diagnosis and serum tests may be positive for specific anti-steroid antibodies. These complementary explorations are however difficult to perform and interpret and definitive diagnosis is based on an association of clinical findings, skin tests, laboratory tests and the clinical course. In case of progesterone sensitization, the treatment of choice is estrogen inhibition of ovulation. For estrogen sensitization, anti-estrogen treatment appears to be more effective. Finally, bilateral ovariectomy may be required in difficult cases.

[Thaumetopoea pityocampa caterpillar and man. Morphology of its venom apparatus. Epidemiological investigation (author's transl)]. / La chenille processionnaire (Thaumetopoea pityocampa Schiff. lépidoptères) et l'homme. Etude morphologique de l'appareil urticant. Enquête épidémiologique.

The combination of a mechanical phenomenon (penetration of the hair) and a chemical phenomenon (discharge of a toxic substance) accounts for the pathological symptomatalogy induced by the processional pine caterpillar. Epidemiological study has pin-pointed the regions infested by the pine caterpillar and has described in detail the dermatitis inflicted by this caterpillar with special emphasis on the frequency of ocular lesions. Also, a close correlation was noted between the geographical density of the populations of Thaumetopoea pityocampa Schiff and the geographical density of the clinical cases recorded. Skin tests have confirmed that the urticant substance is histamino-liberating. A morphological study of the urticant apparatus of this caterpillar ("mirror" and urticant hairs) was undertaken with the scanning electron microscope. The progressive coming into place of the bristles on the cuticular pads of the "mirror" was followed during the last three larval stages (L3, L4 et L5). The urticant hair, hollow on the inside, carries pointed spikes directed towards its distal end. There is no hole or pores on the hair and the necessity to grind the bristles in order to extract the urticant substance leads us to believe that the hair is really a bulb which must be broken, for example in the skin, in order to release its urticant substance (histamino-liberating).

[Multicenter survey related to the frequency of positive patch tests with mercury and thiomersal]. / Enquête multicentrique relative à la fréquence des tests épicutanés positifs au mercure et au thiomersal.

A multicentric study concerning the frequency of positive allergic patch test reactions to mercury and to thiomersal has been conducted in France and in Belgium among 2,000 adult patients submitted to routine patch testing. 73 (3.6 p. 100) patients had a positive patch test to mercury and 47 (2.3 p. 100) to thiomersal, 22 (1.1 p. 100) reacted positively to both mercurials. These high figures are most probably in relation with a broad use of mercurials in both countries, as antiseptics as well as preservative agents in topical drugs. They lead to a careful use of mercurials, which have to be avoided when they can be advantageously replaced by other antiseptics or preservative agents. As far as cosmetics are concerned, the use of mercurials (chemical nature and concentration) is restricted by a Recommendation of the European Council.

[French Guiana "papillonite" (lepidopterism). Clinical and epidemiological study]. / La papillonite de Guyane Française. Etude clinique et épidémiologique.

Clinical studies by Dr R. Pradinaud (Cayenne) has given prominence to the symptoms of "papillonite": its primary and secondary cutaneous lesions, their localisation and evolution as well as its accompanying symptoms such as respiratory pathology. Epidemiologic survey shows a parallelism between the occurrence of papillonite and the presence of the moth Hylesia urticans. The urticant apparatus of this moth was studied with the scanning electron microscope. "Arrow" (fléchettes) were found and they more or less resemble the urticant apparatus of Thaumetopoea pityocampa Schiff caterpillar. The mechanism of action has been studied in the animal and in humans. Extracts prepared from the "arrows" have been rested in vivo guinea-pigs (bleu Evans, Liacopoulos et al.). The findings seem to incriminate an histamino-liberation.

[Allergy to preservatives]. / Allergie aux conservateurs.

This study concerns 465 patients with dermatitis. The clinical history suggested allergy to cosmetics, drugs, industrial products or clothes. These patients were tested with 29 preservatives chosen among the most frequently employed or most sensitising products. Seven french clinics of Dermatology were involved in this study during one year. The patients' age varied between 2 years old and 80 years old. Positive reactions were seen mostly with formaldehyde (4.7 p. 100), Bronopol (4.7 p. 100), ammoniated mercury chloride (3.8 p. 100), benzoic acid (2.1 p. 100), sodium benzoate (1.9 p. 100), parabens (1.9 p. 100), dichlorophen (1.7 p. 100), chloracetamid (1.5 p. 100), benzyl benzoate (1.5 p. 100), Germall 115 (1.2 p. 100), butylhydroxyanisol (1 p. 100) and Dowicil (0.8 p. 100). The incidence of sensitivity to formaldehyde, Bronopol, ammoniated mercury chloride is too high; their use should decrease. Patients sensitive to benzoic acid, benzyl benzoate are not rare. Chloracetamid whose frequency of uses seems to be rather low is a very sensitising product. Parabens which are widely used were seldom found positive; nearly all cases are caused by topical medications.

[Diagnosis of dermatitis due to plants]. / Diagnostic d'une dermite due aux plantes.

Contact dermatitis from plants may occur by several mechanisms. It may arise as a result of simple irritation or by allergic mechanism; co-exposure to sunlight can evoke the phenomena of phototoxicity or photoallergy. Etiologic diagnosis require botanical, chemical and immunologic knowledges. Patch testing can be performed with pure allergens (primin, sesquiterpene lactones etc.), plant extracts (balsams, oleoresins etc.) or with the plant itself. The validity of patch test results is often difficult to determine: false positive reactions due to the presence of pesticides or herbicides, active sensitizations, cross-reactions.

Molecular aspects of allergic contact dermatitis to plants. Recent progress in phytodermatochemistry.

A classification of plants based on the chemical structures of their skin sensitizers is presented. A whole range of chemical structures of contact sensitizers exists in plants containing sesquiterpene lactones (Compositae, Frullania, Lauraceae etc.), tulipalin (Tulipa, Alstroemeria etc.), quinones (Primula and tropical woods), long chain phenols (Anacardiaceae, Ginkgoaceae) and miscellaneous structures such as aldehydes, ketones, terpene hydrocarbons etc. Knowledge of allergens in various plants allows prediction of cross-reactivity.

Usefulness of the European standard series for patch testing in children. A 3-year single-centre study of 337 patients.

Results of patch tests in 337 children aged 1 to 15 performed in our paediatric unit during the past 3 years have been analysed retrospectively in order to optimize the patch test series and to assess their relevance. This study represents the most important single-centre study reported so far over a short period. We found a positive patch test rate of 66%, with a peak incidence among children less than 3 years of age (88% versus 58.9%). The most common allergens were metals, especially nickel, fragrances and, less frequently, rubber chemicals. Concerning nickel, positive reactions rarely correlated with a relevant exposure and were difficult to interpret, especially in patients with atopic dermatitis, who are probably more likely to have irritant or false-positive reactions to metals. Based on the results and their relevance, we propose a shortened standard series of patch tests for paediatric patients.