What is the appropriate duration of a therapeutic trial in cutaneous tuberculosis? Further observations.

BACKGROUND: Laboratory tests for the diagnosis of cutaneous tuberculosis lack adequate sensitivity and specificity and a trial of therapy is often used as a diagnostic test in difficult cases. However, the duration for which the trial should be undertaken is not clearly defined. Our previous study indicated that one month of therapy was adequate to detect a clinical response to treatment. However, about half the patients first reported after one month of treatment, some much later. METHOD: We therefore analysed the treatment records of 107 patients who received four-drug, short course, antitubercular therapy for a diagnosis of cutaneous tuberculosis in our hospital and who were asked to return for follow-up at biweekly intervals in the first month of treatment. RESULT: Twenty-one patients did not return for any follow-up visit, nine patients did not respond to treatment and treatment was stopped in one patient. Of the remaining 76 patients, 72 patients were recorded to have distinct clinical improvement within five weeks of starting treatment while only four patients showed improvement after 60-123 (8-17 weeks) days of therapy. CONCLUSION: These findings indicate that five weeks appears to be an adequate duration of a therapeutic trial in patients suspected to have cutaneous tuberculosis, with the exception of tuberculids and patients showing minimal clinical activity before treatment. Patients who have not responded by this time are unlikely to do so with further treatment and should have their diagnosis reviewed.

Failure of titer of contact hypersensitivity to correlate with clinical severity and therapeutic response in contact dermatitis caused by parthenium.

BACKGROUND: The titer of contact hypersensitivity (TCH) has been used to determine the degree of contact hypersensitivity in patients with contact dermatitis. The values have been found to vary in different individuals and also in the same individual at different times apparently due to the varying severity of the disease. We evaluated the correlation of TCH with disease severity and therapeutic response in patients of contact dermatitis caused by the plant Parthenium hysterophorus. METHODS: Forty-two patients, 30 (71.4%) males and 12 (28.6%) females, aged between 30-75 years, having air-borne contact dermatitis to Parthenium hysterophorus for 0.5-20 years were included in the study. The disease severity and TCH at baseline were recorded in all the patients. They were treated with azathioprine and followed up every month for 4-69 months. The TCH was repeated every 3 months and the last recorded TCH value was taken for analysis in each patient. RESULTS: The baseline clinical severity score (CSS) varied from 10-80 (mean +/- SD: 35.47 +/- 19.41) in these patients. It ranged from 10-30 in 22 (52.4%) patients, from 31-50 in 14 (33.3%) patients, and was more than 50 in 6 (14.3%) patients. The baseline TCH to Parthenium was undiluted (UD) in 2 (4.8%), 1:10 in 15 (35.7%), 1:100 in 20 (47.6%), and 1:1000 in 5 (11.9%) patients respectively. At the end of the study, the clinical severity of the disease decreased in most of the patients. The CSS came down to 0 in 31 patients, to 10-20, and to 50 in 4 patients each, but remained stable in three patients who had baseline CSS from 20-40. The overall mean CSS came down from 35.47 +/- 19.41 to 4.76 +/- 9.43 (p = 0.002). However, there was no significant change in the TCH levels over time (p = 0.153). The last TCH value was negative in 2 (4.8%) patients, undiluted in 5 (11.9%), 1:10 in 10 (23.8%), 1:100 in 18 (42.9%), and 1:1000 in 7 (16.7%) patients. There was no change in the TCH values in 16 (38.1%) patients while it increased or decreased by 1-2 dilutions in 12 (28.6%) patients each. CONCLUSIONS: We therefore conclude that the TCH does not correlate with the clinical severity of contact dermatitis or response to treatment.