Diagnosis

The clinical picture may be sufficient to confirm the diagnosis of CDLE. If in doubt, skin biopsy may be performed. The presence of red, scaly circular lesions on light-exposed skin is suggestive. Detachment of an adherent scale from a lesion will reveal the characteristic plug that has occupied the pilosebaceous follicle - the carpet tack or tin tack scale. In a small number of cases, circulating antinuclear antibodies may be detected.

If in doubt, a skin biopsy of

• a fresh lesion - for histopathology
• an old lesion - for immunofluoresence may be performed to confirm the diagnosis (1)

Reference:

• 1. Nayla Idriss et al. Dark brown scaly plaques on face and ears. JFP 2006; 55(6)