Rash (or other dermatologic complaints) are often difficult for internists to deal with, as we often lack a lot of experience with them. However, going back to basics, a few key points to make are:
(1) A description of the rash is important. This includes the features of the lesions (i.e. macules, papules, plaques, nodules, bullae, etc), a description of the distribution (localized vs. diffuse, major regions of the body affected, areas spared) and the progression of the lesions over time. It is also important to describe the associated symptoms - fever, pruritis, pain, parasthesia or anasthesia, etc.
(2) Rule out acutely dangerous things. A few key rashes internists should know about are:
- Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis
- Pemphigus
- Infections of skin/soft tissue (in particular, necrotizing fasciitis)
- Purpura fulminans (meningococcemia)
- Staphylococcal toxic shock
- Viral exanthems (Note that varicella, measles, etc can be severe and even fatal in adults, especially the elderly)
(3) If in doubt, stop all possible offending drugs and get an urgent dermatology opinion and biopsy.
We talked in more detail about leukemia cutis, a disease caused by infiltration of the skin with leukemic cells. The Canadian Medical Association Journal recently published a short case report with images (although in a child) on this syndrome. Leukemia cutis may portend a worse prognosis in adults with AML.
