Biomedical subjects
Publications and source records attributed to P G Van der Valk.
Toxic pustuloderma is an acute pustular eruption of the skin occurring a few days after the initiation of treatment with the responsible drug. A case of toxic pustuloderma following treatment with the antihistamine clemastine is now reported.
Application of sodium dodecyl sulphate (SDS) on the skin of healthy volunteers was used as a model for acute chemical injury. The time course of the response with respect to cell proliferation was studied using ornithine decarboxylase (ODC) activity. Erythema, polymorphonuclear leucocyte (PMN) infiltration, and the induction of epidermal antiproteinase activity (SKALP/elafin) were used as markers for the inflammatory response. ODC induction was similar to that in other models of acute skin injury, such as tape-stripping and ultraviolet light radiation. The amount of PMN infiltration correlated with erythema, but not with ODC induction. In contrast with findings in the tape-stripping model, no induction of SKALP/elafin activity was found after SDS application. We conclude that cell proliferation as measured by ODC induction is a common feature in the various models for skin injury. Both the kinetics and the intensity of the inflammatory response, and the induction of epidermal antiproteinase activity, appear to vary, depending on the specific model.
The effect of site on the irritant dermatitis potential was studied in 10 subjects using the volar surface of the forearm. Erythema scoring and transepidermal water loss (TEWL) measurements were used to assess irritation at different levels on the forearm. A sodium lauryl sulphate (SLS 2 g/v%) solution was used as a standard irritant in a patch test procedure and on open tests. Both the erythema scores and measurements of the TEWL of exposed skin showed significant localization differences, and demonstrated that the same sites on the forearm should be used for irritancy tests and possibly physiological studies.
Occlusion often, but not always, enhances percutaneous absorption and thus may facilitate skin irritation. Quantitative data about the impact occlusivity may have on minimal irritant stimuli to which the skin is exposed in daily life, and which may lead to chronic irritant contact dermatitis, are however lacking. Irritant stimuli were administered by repeated application of sodium lauryl sulfate (SLS) in an open application procedure. After the open exposure, the skin was either left open or occluded with plastic. Skin irritancy was assessed by means of visual grading and by transepidermal water loss (TEWL) measurements. Post-exposure occlusive treatment markedly enhanced the irritant response. 5 consecutive daily applications produced more irritation, with or without occlusion, than alternate day application. Occlusion may be a relevant factor in the development of irritant contact dermatitis from certain chemicals.
Dithranol short contact treatment is usually applied once a day. For some patients this does not fit their possibilities or needs. Therefore we investigated the efficacy of two other treatment strategies in two small groups of patients. In the attempt to shorten the treatment time, one group of patients was treated twice daily. In order to not withhold short contact dithranol treatment from patients who are unable to perform the treatment daily or at home, a thrice-weekly treatment regimen was studied. 8 patients were treated twice daily and all achieved at least a 90% reduction of the area of involved skin (clearance) within 12.3 (+/- 1.6) weeks. In the thrice weekly group six out of eight patients achieved a clearance of their psoriasis within 13.1 (+/- 4.2) weeks. The aim of shortening the treatment period was not achieved by twice daily treatment in a day-care centre. However, the thrice-weekly treatment regimen certainly appeared to be an effective one. Further studies are needed on larger populations of patients to find out the optimal regimen for intermittent dithranol short contact treatment.