To the Editor: World Health Organization (WHO) has included the tourniquet test as a criterion for probable dengue, and a positive test reflects both capillary fragility and thrombocytopenia [1]. However, this test has a greater positivity rate in individuals with more severe forms of the disease but cannot exclude dengue infection [2,3,4]. Moreover, the test requires a sphygmomanometer and a time duration of at least 5 min. We describe here a simpler alternative to the tourniquet test, the arm blanch test (ABT) which may be useful in making a clinical diagnosis of dengue early.

The physician should make a firm grip of the child’s arm with his/her bare hand, sustain the pressure for 30 s and then release the grip. The skin surface of the arm beneath the physician’s fingers will be blanched and with release of pressure, erythematous margins will be noted around the blanched areas. These children with a positive ABT developed other clinical features of dengue including skin and palmar erythema on follow-up. They also had hematological and serological investigations supporting the diagnosis of dengue. Normal fair-skinned children may have mild transient erythema with ABT. However, the erythema noted with children with dengue will be striking. As we blanch the skin, ABT can be useful even in children with a dark tan. ABT can be quicker than the tourniquet and can be a potential screening test even before the appearance other obvious signs of dengue. This clinical observation should be validated by a well-designed study. If we can do ABT and the tourniquet test in different arms of the same child with probable dengue, and correlate the clinical findings with serological parameters (in a good sample size), we can derive more meaningful conclusions.