An elderly man sought dermatology consultation for gradually progressive, mildly itchy, photosensitive rash on dorsum of hands for a month. Apart from the skin lesions, he also complained of intermittent diarrhoea which he attributed to his underlying Crohn's disease. He additionally had difficulty in recalling recent events for last few months. On examination (Fig. 1), well demarcated erythematous to dusky edematous plaques were noted symmetrically on dorsal aspect of hands and fingers. Skin of no other part was involved.