Physiopathology of acetylcholine delayed blanch in atopics. Thermographic study (author's transl)

Controversy subsists about interpretations of "delayed cholinergic blanch" in atopic dermatitis. A physical approach of this vasomotor phenomenon using infrared and cholesteric thermography and direct recording of skin temperature shows that the delayed blanch is hyperthermic and cannot be the effect of a paradoxal cholinergic vasoconstriction. In the light of the beta-adrenergic blockade theory of Szentivanyi a new physiopathological interpretation is proposed.     

Expression of CD30 on T helper cells in the inflammatory infiltrate of acute atopic dermatitis but not of allergic contact dermatitis

The CD30 molecule has been proposed as a marker for a subset of CD4+CD45RO+ (memory) T cells with potent B cell helper activity producing IL-5 and IFN-gamma and as a specific marker for Th2 cells. Recently, an association has been demonstrated between elevated serum levels of soluble CD30, which is shed by CD30+ cells in vitro and in vivo, and atopic dermatitis but not respiratory atopic disorders or allergic contact dermatitis. We studied the expression of CD30 in the inflammatory infiltrate of atopic dermatitis compared with that of allergic contact dermatitis, with special regard to skin disease activity (acute vs subacute/ chronic). Biopsies were obtained from 16 patients suffering from atopic dermatitis (acute n = 6, subacute/ chronic n = 10), from 7 patients with acute allergic contact dermatitis and from 5 positive patch-test reactions. Paraffin-embedded as well as snap-frozen material was stained with anti-CD30 and anti-CD45RO mAbs according to standard procedures. Double-staining procedures for CD30CD3, CD30CD4, CD30CD45RO and CD30CD68 were also performed. Abundant CD45RO+ cells were detected both in atopic dermatitis and in allergic contact dermatitis lesions. We found scattered CD30+ cells in only one of six formalin-fixed paraffin-embedded acute atopic dermatitis biopsies, but in all of the respective snap-frozen specimens, possibly because CD30 expression on atopic dermatitis infiltrating cells is weak and sensitive to formalin fixation and paraffin embedding. CD30CD3 and CD30CD4 double staining identified CD30+ cells to be helper T lymphocytes. No significant CD30 expression (either in paraffin-embedded or in frozen material) could be found in subacute/chronic atopic dermatitis lesions or in any of the specimens of allergic contact dermatitis. The results suggest a specific regulatory function of CD30+ T cells in acute atopic dermatitis. With respect to the view that CD30 is a marker for Th2 cells, our observations confirm previous findings that Th2 cells predominate in the infiltrate particularly of acute atopic dermatitis. CD30 expression in acute atopic dermatitis but not in acute allergic contact dermatitis might be helpful in the histological differentiation of these disorders and in the further characterization of atopy patch testing.     

Percutaneous electrical nerve stimulation (PENS): a complementary therapy for the management of pain secondary to bony metastasis

BACKGROUND: Metal skin clips are used in surgery. They may contain metals that might cause allergic reactions and delayed wound healing. METHODS: The metal composition of 18 different surgical clamps was examined. The allergy status of 184 patients was determined by patch tests and was correlated with the clinical outcome of wound healing after application of skin clips. RESULTS: Skin clips contained chromium, nickel, molybdenum, cobalt, and titanium in concentrations high enough to cause allergic reactions. Eighteen percent of the men and 23% of the women were sensitive to nickel and 16% of the men to chromium. We found a positive correlation between the grade of nickel allergy and the reaction to the skin clips. CONCLUSIONS: Our study suggests that allergic reactions and delayed wound healing can be caused by the use of surgical skin clips. Therefore skin clips are not recommended for patients with a history of contact dermatitis to metals and/or atopy.     

Induction of atopic dermatitis by inhalation of house dust mite

BACKGROUND: The pathogenetic role of house dust mite in atopic dermatitis remains controversial. Recent studies have shown that intensive epicutaneous contact of house dust mite allergen with premanipulated skin may induce dermatitis. It is, however, uncertain whether such conditions are met during natural contact with house dust mite. In the past, allergen inhalation has been suggested to induce exacerbation of atopic dermatitis. The aim of this study was to investigate whether dermatitis could be induced in patients with atopic dermatitis by inhalation of house dust mite. METHODS: Twenty patients with atopic dermatitis underwent bronchial provocations with house dust mite. Challenge tests were performed with four concentrations of a standardized house dust mite extract in a double-blind, randomized, placebo-controlled fashion. Spirometry was performed, and FEV1 was measured before and after each challenge dose. Changes in severity or localization of itching or erythema were recorded. RESULTS: In nine of 20 patients with atopic dermatitis bronchial challenge with house dust mite induced unequivocal skin symptoms after 1.5 to 17 hours. Pruritic erythematous lesions on noninvolved sites together with exacerbations of existing lesions were seen in three patients. Three patients had an exacerbation only, and three other patients had new lesions only. In eight of nine patients with house dust mite inhalation-induced dermatitis, skin symptoms were preceded by an early bronchial reaction. All patients with house dust mite-induced dermatitis had a history of asthma, and as a group they had a higher mean blood total IgE level compared with the "negative skin responders." One patient had pruritic erythema on the placebo challenge day, without a preceding bronchoconstrictive reaction. The number of patients who had a skin response on the house dust mite challenge day was significantly higher than the number of patients who had a skin response on the placebo day (p = 0.011 [Prescott's test]). CONCLUSIONS: The respiratory route may be relevant in the induction and exacerbation of dermatitis in a subset of patients with atopic dermatitis who have early bronchial reactions after house dust mite inhalation, a history of asthma, and an elevated blood total IgE level. Furthermore, these findings suggest a possible causal relationship between bronchial reactions and skin reactions.     

Bronchial and cutaneous responses in atopic dermatitis patients after allergen inhalation challenge

BACKGROUND: Atopic dermatitis (AD) is often associated with allergic asthma (AA). Inhalation of allergens influences the activity of AA but the effect on the skin in AD is unclear. OBJECTIVES: We evaluated the degree of bronchial hyperresponsiveness to methacholine in eight AD patients with AA (AD+) and eight AD patients without AA (AD-) and studied bronchial and cutaneous responses after allergen inhalation challenge. METHODS: All patients were treated in hospital for their eczema with tar ointment (pix liquida) and orally administered antihistamines (mean hospital stay 37 days). After clearing of the skin lesions allergen inhalation challenge was performed. Cutaneous responses were studied by measuring the 'Costa' score before and 24 h after allergen inhalation challenge. RESULTS: The median value of the provocative concentration of methacholine causing a 20% fall (PC20 Mch) in forced expiratory volume in 1 second (FEV1) was significantly higher in the AD- group compared to the AD+ group with median values of 10.70 and 0.60 mg/mL, respectively. These values did not change significantly in both groups during hospital stay. After challenge all AD+ patients showed early and late asthmatic responses whereas only four AD patients showed early asthmatic responses (mean values of the maximal fall in FEV1 during the EAR 37%/16% and in PEF during the LAR 27%/4% for AD+ and AD-patients, respectively). The 'Costa' score increased in both groups (mean score before 19.1/24.4 and after challenge 26.8/26.9 for AD+ and AD- patients, respectively). The increase in the AD+ group was significantly higher compared with the AD- group (P=0.016). CONCLUSION: We conclude that allergen inhalation challenge causes a flare up of the skin lesions in atopic dermatitis patients. This was more prominent in atopic dermatitis patients who already suffered from an IgE-mediated allergic inflammation in the lung.     

Isolation of three species of mites from house dust of atopic dermatitis patients in Qualyobia Governorate, Egypt

Dermatitis or inflammation of the skin caused by an outside agent, is a condition with many causes. It may result from direct irritation of the skin by a substances (chemical or insecticide) or it may be an allergic reaction to a particular substance that has been in contact with the skin as soap or detergent or insect urticating hairs; injected as insect saliva or faeces or sting or taken by mouth as food or drug. In general, treatment of dermatitis depends mainly upon the cause. In the present study, three species of mites were isolated from the dust collected from houses of atopic dermatitis patients. These mites were Dermatophagoides pteronyssinus, Ornithonyssus bacoti and Haemogamasus pontiger. The former species was the predominant one which is known to produce the most potent allergen. It was concluded that house dust mites are one of the aetiological factors of atopic dermatitis and that genera of mites other than Dermatophagoides may be considered as allergen in house dust mites.     

Immunopathologic disorders in atopic dermatitis

The atopic dermatitis is a multifactorial inheritable disease, in which pathogenesis in addition to environmental factors (climate, allergens, clothing) genetically determined multiplex metabolic differences (arachidonic acids, essential fatty acids) and immunologic alterations play an important role. Within immunologic findings the disturbances of balance in Th1 and Th2 subclasses, the increased degranulation activity of mast cells and the increased antigen presentation activity of Langerhans cells can be stressed. The clinical immunological alterations shown in the diseases, the increased production of IgE and so the type I. allergic reactions (urticaria, gastrointestinal manifestation of food allergy, allergic rhinitis, asthma bronchiale), the difference of cellular immunity of the skin can be explained by the above mentioned main immunological changes. In understanding of immunological origin of atopic dermatitis the IgE receptors expressed on the surface of Langerhans cells (connecting the immediate and delayed type of immune response) mean significant help.     

Hospital infections and their prevention in dental clinics

The normal flora is typified by the yeast-like fungi Malassezia (Pityrosporum). Successful attempts at treating patients with atopic and seborreic dermatitis, pityriasis versicolor, and psoriasis with antifungicides confirm the involvement of these fungi in the etiology and development of these diseases. In patients with various skin diseases, an immune response to M. furfur is specific. In those with psoriasis, it is characterized by the higher chemoatractant activity of polymorphonuclear leukocytes stimulated by a M. furfur extract and by the immune response of IgG antibodies with immunoreactive proteins having a molecular weight of 100-120 kD. Patients with atopic dermatitis show a hyperimmune IgE-mediated response to M. furfur, with its specific Th2-lymphocytes inducing the atopic cytokines (IL-4, IL-10) that stimulate allergic reactions to other allergens. Those with pityriasis versicolor had impaired keratinocytic pigment exchange due to azelainic acid produced by M. furfur. The cause of transformation of the yeast phase of M. furfur to the mycelial one is presumably to be changes in the composition of fatty acids of the sebaceous glands due to increased androgen concentrations.     

Mechanisms of resolution of allergic contact dermatitis

Photoallergic and allergic contact dermatitis are examples of type IV hypersensitivity reactions that involve T cell-mediated immune responses against haptens that come into contact with the skin. These two types of allergies differ in that for routine contact allergens, the hapten is usually a chemically reactive species that readily couples to host proteins; for photoallergic reactions, UV light (320 - 400 nm) is necessary to generate ("photoactivate") the chemically reactive hapten. From this point on, both photoallergic and allergic contact dermatitis are likely to proceed along the same pathways. For both types of cutaneous delayed-type hypersensitivity, there are naturally occurring mechanisms that terminate this type of T cell-mediated inflammation (tolerance induction). An important tolerance mechanism in the skin involves the induction of T-cell clonal anergy by "amateur" antigen-presenting cells such as keratinocytes. Advances in the understanding of the molecular pathways of T-cell activation and inactivation by antigen-presenting cells have identified critical signaling molecules such as B7/BB-1 antigen. The overexpression of these signaling molecules by the keratinocytes of transgenic mice disrupts the normal kinetics of resolution of murine contact hypersensitivity. These animals have prolonged contact hypersensitivity reactions that resemble some chronic dermatologic conditions in humans. This animal model may be a useful tool to better understand chronic allergic and photoallergic contact dermatitis.     

Active immunization of Merino ewe lambs with recombinant bovine alpha inhibin advances puberty and increases ovulation rate

The incidence of allergic contact dermatitis from neomycin evaluated in relation to 1381 verified cases of allergic contact dermatitis showed a progressive increase (5.00, 7.69, 10.18%) over a three-year period (1990-1992). Sensitivity to neomycin was investigated with special reference to possible cross-reactions between neomycin and the allergens that are commonly used in the manufacture of cosmetic products. Contact sensitivity to neomycin was found to be present with the other diagnoses, such as atopic dermatitis, seborrhoeic dermatitis, hypostasic dermatitis and psoriasis vulgaris.     

Hypothalamic self-stimulation and operant activity in the mottled mutant mouse

Cell-mediated immunity to bacterial antigens was studied by intradermal testing, and to contact antigens (cosmetics, environmental chemicals and topical medicaments) by patch testing in 270 children with atopic dermatitis. The incidence of delayed-type immune cutaneous reactions in these patients was lower than in the controls. Contact allergy is a rare finding in the first 4 years of life but its incidence increases subsequently. In subjects with atopic dermatitis the incidence of sensitization by contact with allergens contained in topical medicaments proved to be lower than in subjects with eczema of other types. The data collected points to a reduced cell-mediated immune reactivity in a proportion of subjects with atopic dermatitis.     

Allergic contact dermatitis: clinical features and profile of sensitizing allergens in Riyadh, Saudi Arabia

BACKGROUND: No reports are available on allergic contact dermatitis in Saudi Arabia, although it seems to be a common skin problem. We attempted to explore certain clinical aspects in addition to the profile of sensitizing allergens in our area. As no standard panel for patch testing is available in our geographic region, we examined the suitability of the European Standard Series. METHODS: Patch testing was performed on 271 consecutive patients with various forms of dermititis, referred for evaluation of possible allergic contact dermatitis. The study included 147 women and 124 men. The patients were between 12 and 75 years of age. RESULTS: Out of 271 subjects, 152 (56.1%) showed one or more positive reactions. Of these, 80 (52.6%) were women and 72 (47.4%) were men. Almost one quarter of the patients (25.7%) presented with hand dermatitis. Positive reactions to 21 out of the 22 allergens were found. Sensitization was most common to nickel sulfate (39.5%), potassium dichromate (32.9%), and cobalt chloride (30.9%). Reactions to the other allergens ranged between 14.5% and 1.3%). Less than one percent of the patients (0.66%) reacted to benzocaine and showed no reaction to primin. CONCLUSIONS: Allergic contact dermatitis is a common skin problem in Saudi Arabia. Further studies that address the prevalence and incidence of the disease are indicated. The European Standard Series is suitable for patch testing patients in our community; however, we suggest exclusion of benzocaine and primin. The addition of three allergens of local relevance, black seed oil, local perfume mix, and henna, are presented and discussed. The formulation of a regional standard series for patch testing dermatitis patients in our geographic area requires further collaborative studies.     

Circulating skin-homing T cells in atopic dermatitis. Selective up-regulation of HLA-DR, interleukin-2R, and CD30 and decrease after combined UV-A and UV-B phototherapy

BACKGROUND: As the cutaneous lymphocyte-associated antigen appears to detect circulating T cells that migrate to the skin in atopic dermatitis but not T cells that migrate to mucosal sites in allergic asthma and rhinitis, we investigated T-cell activation markers and CD30 on the cutaneous lymphocyte-associated antigen-positive circulating T-cell subset in atopic dermatitis to see whether these markers are different from those in normal controls and related to disease activity. DESIGN: Open study. SETTING: University referral center. PATIENTS: Twelve patients with atopic dermatitis and 12 healthy controls. INTERVENTION: Combined UV-A and UV-B treatment for 2 months. MAIN OUTCOMES MEASURES: Percentage of circulating cutaneous lymphocyte-associated antigen-positive T cells that express HLA-DR, interleukin-2 receptor, CD69, CD71, and CD30 (triple-color flow cytometric analysis). Clinical score, Dermatology Life Quality Index, pruritus score, and consumption of topical corticosteroids were determined. RESULTS: Increased relative numbers of cutaneous lymphocyte-associated antigen-positive T cells expressing HLA-DR, interleukin-2 receptor, and CD30 were found in patients with atopic dermatitis before treatment. Treatment with UV-A and UV-B was associated with clinical improvement and a decrease of levels of HLA-DR, interleukin-2 receptor, and CD30 in cutaneous lymphocyte-associated antigen-positive T cells. HLA-DR on cutaneous lymphocyte-associated antigen-positive T cells correlated significantly with the clinical score. CONCLUSION: Expression of HLA-DR and interleukin-2 receptor is a sensitive marker of disease activity in atopic dermatitis. Apart from giving information on disease activity in atopic dermatitis, the availability of skin-seeking T cells in the blood offers the opportunity to obtain further information on T cells that may have effector function in the skin.     

Allergic and immunologic skin disorders

The skin represents a unique immunologic organ poised to protect the host from invading organisms and environmental antigens. The skin is also an important target for a variety of allergic and autoimmune responses. Mast cells are key to the pathogenesis of urticaria, angioedema, and mastocytosis. Atopic dermatitis is the consequence of an immunoregulatory abnormality resulting in a skin-directed T helper type 2 response. Allergic contact dermatitis is an example of classic delayed type hypersensitivity. Circulating autoantibodies against the epidermis are a key mechanism by which bullous skin diseases occur.     

Persulfate hair bleach reactions. Cutaneous and respiratory manifestations

Ammonium persulfate is widely used to "boost" peroxide hair bleaches. These persulfates can produce a variety of cutaneous and respiratory responses, including allergic eczematous contact dermatitis, irritant dermatitis, localized edema, generalized urticaria, rhinitis, asthma, and syncope. Some of these reactions appear to be truly allergic while others appear to be due to the release of histamine on a nonallergic basis. Patch tests may be performed with 2% to 5% aqueous solution of ammonium persulfate. Scratch tests may result in asthma and syncope. In some patients, merely rubbing a saturated solution of ammonium persulfate into the skin will evoke a large urticarial wheal. Hairdressers should be made aware that these ammonium persulfate hair bleach preparations may provoke severe reactions and should seek medical attention if the client complains of severe itching, tingling, a burning sensation, hives, dizziness, or weakness.     

On the resident aerobic bacterial skin flora in unaffected skin of patients with atopic dermatitis and in healthy controls

In 14 patients with atopic dermatitis the superficial bacteria from unaffected skin were extracted with the scrub method, aerobically cultured, and analysis qualitatively and quantitatively. For comparison, 12 healthy subjects served as control group. Staphylococcus aureus, as well as coagulase-negative staphylococci were significantly increased in patients with atopic dermatitis. It is assumed that special characteristics of the horny layer in atopic dermatitis favor the growth of aerobic bacteria. The qualitative biotyping and phage typing gave no support to the claim that special bacteria dominate the microbial flora of the skin of patients with atopic dermatitis.     

Latent sources of contact allergy]

In individuals sensitized to many contact allergens in the course of 4th immunological mechanism, in whom allergic contact dermatitis develops at the site of exposure to haptens, disseminated eczematous skin lesions might be provoked by latent source of hapten, which penetrates to the body omitting the skin. The most frequent clinical situations include: allergy to drugs, food additives, inhaled chemicals originated from plants, allergic reactions to metal endoprostheses used in orthopaedics and/or dentistry, and all conditions facilitating penetration of hapten directly to the blood through damaged skin (erosions, ulcers, etc.) and/or under occlusive dressings.     

Allergic contact dermatitis to quinones in Paphiopedilum haynaldianum (Orchidaceae)

An eczematous eruption developed on the hands and forearms of a 68-year-old man after frequent contact with homebred specimens of the lady slipper Paphiopedilum haynaldianum. Patch tests with leaves, petals, and stems, as well as with two quinones isolated from the plant by thin-layer chromatography, gave strongly positive reactions. The results demonstrated that the recurrent skin lesions were the expression of an allergic contact dermatitis due to the quinoid constitutnets, which are the main contact allergens in this orchid species.     

Abdominal aortic aneurysms in heart transplanted patients

BACKGROUND: Protein contact dermatitis is a form of contact dermatitis possibly triggered by proteinaceous allergens. MATERIALS AND METHODS: We report two patients with a history of erythematous and urticarial skin reactions followed by transformation into prolonged papular symptoms upon contact with proteinaceous material. RESULTS: The symptoms reported by the patients were reproducible by skin testing with meat (cow) and fish (salmon). Both patients experienced extracutaneous manifestations after ingestion of meat and fish, as proven by oral challenge. Specific immunoglobulin E (IgE) antibodies were detected in the patients' blood. CONCLUSIONS: Both cases meet all major criteria of protein contact dermatitis, suggesting IgE-mediated immediate-type hypersensitivity with late-phase cutaneous reactions.