Lichen planus

•  clinical features of lichen planus can be summarized by the five "P’s"
                  - papules (usually 2-5 mm size)
                  - pruritus (intense)
                  - purple
                  - polygonal
                  - planar (flat-topped)
                  
                  - in addition, individual lesions may show fine white lines on the surface
                    (Wickham’s striae)

•  lesions usually distributed over the flexor wrists and forearms, neck, thighs, shins,
   lumbar back, genitalia

     

     

     

     

     

     

     

     

•  oral mucosal lesions extremely common; in some cases patients may only have oral  
    lesions:
                  - lacy white reticular lesions on the buccal mucosa most common pattern

     

     

•  many drugs can cause "lichenoid drug eruptions" that are clinically indistinguishable
   from the idiopathic form described above