RESUMEN
Traction alopecia (TA) is hair loss caused by prolonged pulling or repetitive tension on scalp hair; it belongs to the biphasic group of primary alopecia. It is non-scarring, typically with preservation of follicular stem cells and the potential for regrowth of early lesions especially if traction hairstyles are stopped. However, the alopecia may become permanent (scarring) and fail to respond to treatment if the traction is excessive and prolonged. Hence, the ability to detect fibrosis early in these lesions could predict patients who respond to treatment. Histopathological diagnosis based on scalp biopsies has been used as a gold standard to delineate various forms of non-scarring alopecia and to differentiate them from scarring ones. However, due to potential discrepant reporting as a result of the type of biopsy, method of sectioning, and site of biopsy, histopathology often tends to be unreliable for the early recognition of fibrosis in TA. In this study, 45 patients were assessed using the marginal TA severity scoring system, and their biopsies (both longitudinal and transverse sections) were systematically assessed by three dermatopathologists, the aim being to correlate histopathological findings with clinical staging. Intraclass correlation coefficients were used to determine the level of agreement between the assessors. We found poor agreement of the identification and grading of perifollicular and interfollicular fibrosis (0.55 [0.23-0.75] and 0.01 [2.20-0.41], respectively), and no correlation could be drawn with the clinical severity score. Better methods of diagnosis are needed for grading and for recognition of early fibrosis in TA.
RESUMEN
BACKGROUND: Isoniazid and ethionamide are important first- and second-line anti-TB drugs (FLDs and SLDs), respectively. Ethionamide is a structural analogue of isoniazid and the two drugs share other similarities, including their metabolism, therapeutic targets, hepato-toxicity patterns and drug resistance. As a result, there has always been concern about possible cross-reactivity between them. METHODS: Among 69 patients with drug rash with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) to FLDs, FLDs were stopped and SLDs added when the skin and laboratory parameters had settled. This was followed by sequential and additive rechallenge with FLDs. We report 25 consecutive cases that developed confirmed cutaneous adverse drug reactions (CADRs) to isoniazid or ethionamide used as FLD and SLD, respectively. RESULTS: Sixty-nine participants who developed CADRs on FLDs were enrolled in the study. Twenty developed a rechallenge reaction to isoniazid and five reacted to ethionamide. Four of the 20 isoniazid cases were patch test positive, 3/20 were skin prick test positive and 13/20 reacted to oral rechallenge. All seven cases that were patch and skin prick test positive were associated with systemic reactions. Twenty of the 25 cases had DRESS and 5 had SJS/TEN. Twenty-three of the 25 cases with rechallenge reactions were HIV infected. Importantly, none of the cases that reacted to ethionamide during the rechallenge reacted to isoniazid and none who subsequently reacted to isoniazid reacted to ethionamide. CONCLUSIONS: Our findings strongly suggest that the risk of cross-reactivity of isoniazid and ethionamide in DRESS syndrome and SJS/TEN is low. These findings have implications for clinical management.
