How big is your hand and should you use it to score skin in cutaneous T-cell lymphoma?

Assessing burn surface area is essential to triage patients and determine fluid resuscitation. The three commonly used methods are: (i) the palmar method, where palmar surface area is assumed to equal 1% of body surface area (BSA); (ii) the rule of nines; and (iii) the Lund and Browder method, where body parts are assigned a percentage surface area. Calculation of BSA involvement in dermatological disease is used to measure disease severity and treatment responses. The grid-point counting method may also be used. Mycosis fungoides (MF), a form of cutaneous T-cell lymphoma, typically presents with patches and plaques with progression to tumours and erythroderma in advanced disease. Quantifying skin involvement in MF requires assessment of both BSA involvement and lesion type. The severity-weighted assessment tool (SWAT) was designed for this purpose, using grid-point counting, and weighting patch as x1, plaque as x2 and tumour as x3. The SWAT was modified in an international consensus paper to use Lund and Browder charts, and the weighting of tumours was increased to x4. The patients' palm or hand is frequently the method of choice for skin scoring. However, both the definition of the palm and whether this includes the fingers or even the thumb, and the percentage BSA assigned to the palm, vary in the literature. A review of published planimetry studies found that the most consistent measure across age and race was the palm without fingers reflecting 05% total BSA. We recommend the use of the patient's palm to represent 05% BSA as the most convenient and reliable tool to measure surface area, and we introduce an iPhone application to record BSA electronically and calculate modified SWAT.