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Biomedical subjects

H Degreef

Publications and source records attributed to H Degreef.

At least 91 records · Page 5Linked to original sources
PubMed1989

Identification of cross-reaction patterns in allergic contact dermatitis from topical corticosteroids.

Contact allergy to topical corticosteroids occurs more frequently than previously supposed. Cross-allergic phenomena are common. On the basis of a review of the literature and our own patch test data on 15 patients, we conclude that positive patchtests to corticosteroids occur approximately six to seven times more frequently in well-defined groups of structurally-related substances than between corticosteroids of different groups. An analogous substitution pattern on the steroid D-ring or the carbon side chain (C20, C21) seems to have a significant influence on the association of positive patchtest results. This is not the case for other structural variables, such as the presence of a double bond in the steroid A-ring or fluoride substitutions on the B-ring. The effect of other factors such as concomitant sensitization and steroid metabolism in the skin on the development of a corticosteroid polyallergy are analysed, and the specificity and sensitivity of cross-allergy phenomena are evaluated. These are important in the selection of a topical steroid in the future treatment of a corticosteroid sensitive patient.

Administration, Topical↗
PubMed1989

Local anesthetic intolerance due to metabisulfite.

The case of a 40-year-old woman with severe edema of the face and neck after the injection of a local dental anesthetic is presented. The reaction is attributed to the presence of sodium metabisulfite, and antioxidant, in the local anesthetic. Both the anesthetic and the sodium metabisulfite gave a delayed positive patch-test response.

Adult↗
PubMed1988

Epidermal Langerhans cells, dermal dendritic cells, and keratinocytes in viral lesions of skin and mucous membranes: an immunohistochemical study.

We wanted to evaluate the eventual expression of viral antigens and MHC class II products by keratinocytes as well as the alterations of epidermal Langerhans cells and dermal dendritic cells in viral lesions of skin and mucous membranes. Therefore we investigated 68 biopsy specimens of protracted viral lesions, such as warts, condylomas, and mollusca contagiosa, and of rapidly resolving viral lesions such as herpes simplex virus infection. For this we used immunohistochemical staining techniques and several monoclonal and polyclonal antisera. In most cases investigated viral antigens (human papilloma virus antigens or herpes simplex virus type 1 antigens) could be demonstrated in keratinocytic nuclei. Except for a few viral lesions in which epidermal Langerhans cells were rather numerous, epidermal Langerhans cells were reduced in number or absent in almost all viral lesions. Moreover, epidermal Langerhans cells and dermal dendritic cells showed changes in morphology, distribution, and immunophenotype. These alterations may be caused by a toxic effect of the virus on dendritic cells. HLA-DR+ keratinocytes could be identified in few viral lesions only; HLA-DQ+ keratinocytes were not seen. Possible explanations for this lack of MHC class II expression by keratinocytes are discussed.

Antigens, Viral↗
PubMed1988

Drug-induced skin reactions and acute cutaneous graft-versus-host reaction: a comparative immunohistochemical study.

Skin biopsies from eight patients with drug-induced dermatitis have been compared with skin biopsies from 16 patients developing skin lesions (acute graft versus host-reaction and/or drug-induced reaction) after bone marrow transplantation. Biopsies were investigated using immunohistochemistry and several monoclonal antibodies. Morphological and immunohistochemical patterns in skin biopsies of both groups were very similar. The only difference seen was a reduced number of epidermal Langerhans cells with poorly developed dendrites in skin biopsies taken from patients who underwent bone marrow transplantation. If the latter finding is due to the cytotoxic drug regimen administered before bone marrow transplantation, as previously stated, we doubt the usefulness of skin biopsies in the differential diagnosis of acute graft-versus-host reaction and drug-induced skin lesions.

Adolescent↗
PubMed1988

Pharmacokinetic profile of orally administered itraconazole in human skin.

Itraconazole is an orally effective antifungal agent with a high affinity for tissues. The skin kinetics in human volunteers have been studied after administration of 100 and 200 mg of itraconazole daily. From day 7 onward, tissue levels in the beard region and on the back were consistently higher than the corresponding plasma levels. The levels in the palmar stratum corneum were lower than the corresponding plasma levels but persisted for 3 weeks after discontinuation of therapy. Stratum corneum levels in the beard area were still measurable 4 weeks after the end of therapy. With the 200-mg dose, sweat levels became detectable 24 hours after the first drug intake. The sweat levels were usually lower than the corresponding plasma levels and followed the same curve as the plasma levels. Sebum levels of itraconazole were 10 times as high as the corresponding peak plasma levels. Sebum levels were undetectable 14 days after discontinuation of therapy. The results indicate that oral intake of itraconazole will result in therapeutic levels in the skin and these levels vary, depending on the region of skin tested. There are at least three routes of delivery of itraconazole to the skin: (1) passive uptake by keratinocytes in the basal layer (as shown by the continued presence of the drug in the palmar stratum corneum at a moment when plasma, sebum, and sweat levels are again undetectable); (2) a less significant excretion through the sweat glands (as shown by the lower drug levels compared with the plasma levels); and (3) a massive excretion through the sebaceous glands (as shown by the sebum levels compared with the plasma levels).

Administration, Oral↗
PubMed1988

UV sunlight and patch test reactions in humans.

No seasonal influence of UV sunlight on patch test reactions in humans over a period of 9 years of clinical practice was found in this retrospective study of almost 8000 patients. Although the mean UV monthly dose varies seasonally, up in the summer and down in the winter, no significant differences could be identified for patch test reactions, either for the mean number of positive test reactions or for the intensity of the skin reaction or for the id-like spread reactions seen in summer or winter. Furthermore, no short-term influences of UV exposure during the weekend preceding patch testing could be demonstrated. Therefore, reliable patch-test results can be expected at any season of the year from a general population, at least in Belgian-type climates.

Belgium↗
PubMed1988

[Bullous pemphigoid in hypernephroma].

The case is reported of a 75-year-old man with bullous pemphigoid that was resistant to conventional treatment with prednisone and azathioprine. A hypernephroma was discovered and surgically excised, whereafter the skin lesions healed completely without any other therapeutic measures being taken.

Aged↗
PubMed1987

Contact and photocontact sensitivity problems associated with thiourea and its derivatives: a review of the literature and case reports.

Thiourea and its derivatives have been widely used in industry since the beginning of this century, but it was only in the late 1960s that reports of cases of contact dermatitis to these compounds began to appear in the literature. This literature is reviewed. We have observed eight cases of diphenylthiourea sensitivity in patients sensitive to adhesive tape. Four cases are presented of sensitivity to thiourea compounds in diazo-sensitized paper. Three of these patients were contact allergic to dimethylthiourea, and the other was contact and photocontact allergic to thiourea. These skin problems were mainly induced by airborne contact.

Adult↗
PubMed1987

Pityriasis versicolor and Pityrosporum ovale. Morphogenetic and ultrastructural considerations.

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been performed on skin material of patients with pityriasis versicolor who were orally treated with itraconazole. Before as well as after therapy, variously sized spherical structures were observed on the surface of the keratinocytes with SEM. TEM examination revealed Pityrosporum ovale, predominantly in its mycelial phase, inside keratinocytes. The spherules as observed by SEM appeared to be amorphous, lipid-like droplets originating from the inside of the keratinocytes. The cytoplasm of the keratinocytes was at least partly occupied by the same amorphous material. It is therefore suggested that P. ovale penetrates the keratinocyte where degradation of the normal keratinous content to amorphous material takes place. This newly formed lipidic substrate may be an essential nutritive factor. The lipidified state of the stratum corneum persisted for at least 3 weeks after eradication of the fungus by itraconazole. It is speculated that the presence of large quantities of this lipid-like material might be the cause of hypopigmentation because it may constitute an ultraviolet light block.

Humans↗