We were pleased that the first national guidelines for paediatric Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN) were published in your journal last year1 . They highlighted the higher rate of infectious triggers in children compared to adults. This message is especially important for us, as author SW's son had SJS/TEN triggered by Mycoplasma pneumoniae, which accounts for up to 50% of infectious causes. SW experienced first-hand the frustration of aetiological uncertainty in this disease. Accurate diagnosis of Mycoplasma-induced SJS/TEN is important as it allows for continuation of simple analgesia (otherwise implicated as a possible trigger), possible avoidance of further drug allergy testing (which can be inconclusive), focused treatment of Mycoplasma with antibiotics, and management of recurrence risk.