Derm SAQs ·
Wood lamp / fluorescence examination — SAQ
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A registrar hands you a Wood lamp in a poorly lit corridor and asks you to “check if this rash fluoresces.” The patient has axillary brown patches, scattered hypopigmented truncal macules with fine scale, and a school-age child at home with patchy scalp scale.
Questions
a) State the radiation band used and two essential technical conditions for a valid examination. (2 marks)
b) Give the classic Wood-lamp colour association for erythrasma and for pityriasis versicolor. (2 marks)
c) The child’s scalp does not fluoresce. Does this exclude tinea capitis? Explain with reference to organisms. (3 marks)
d) List three causes of false-positive fluorescence and one situation in which urine fluorescence should trigger further tests. (3 marks)