Well, if ever there were a great out-of-the-blue case, this is it. This patient was scheduled to see us for an unspecified rash, and when we scheduled him, he forgot to keep the appointment. When we saw him, he had this rash in a necklace distribution, rash on the dorsal hands, also on the back of his neck. He had been complaining of diarrhea and lethargy, and all this despite eating a relatively varied diet.
His PCP says he's in pretty good shape, but I'm not so convinced. The rash is classic for Casal's Necklace, and the diarrhea and confusion (pre-dementia?) would certainly make one think this patient has pellagra. In that case, two things to do: First, start him on Niacin supplementation. Second, get him a workup for a carcinoid tumor. That's the PCP's job, but we advised the PCP on the reasonable route to evaluation.
What else could it be? Well, photoallergic contact dermatitis could theoretically give one this kind of rash, should he be allergic to something he is applying to the skin, such as sunscreen, but he is unlikely to have this problem since he is African American. Other than that, and ESPECIALLY in the face of the associated symptomatology, this is pellagra until proven otherwise.
This month's winner is Karen, from the Tampa area. She will be hoovering up some fine Pinot Noir wine from her local wine distributer, and will forward a picture soon.