Dermatology for the Internist

Dermatology for the Internist

Lecture by Dr. Sarah Wolfe. Summarized by Dr. Eric Wei

Epic Tricks

  • General Dermatology Order Sets!
    • Type in “Gen Derm” into the order section and numerous order sets will come up to treat common conditions including acne, atopic dermatitis, urticaria, hidradenitis, psoriasis. This is a great place to start as it highlights first, second, and third line treatment options

The language of dermatology

Primary features:

  • Macule: flat, < 1cm
  • Papule: elevation of any type, < 1 cm
  • Patch: flat, > 1 cm
  • Plaque: elevated, > 1cm
  • Nodule: like plague but dome shaped

Secondary features:

  • Crust
    • Hemorrhagic Crust (aka scab)
    • Yellowing of the crust–> suggests superficial infection with staph/strep
  • Scale
  • Fissure
  • Lichenification
  • Erosion
  • Ulceration


  • Erythematous, white, purple, brown, yellow, black, etc.


  • Examples:
    • atopic dermatitis commonly distributed where shoe rubs feet
    • candida likes pannus, chest, moist areas
    • Psoriasis – interdigital and plantar surfaces of the toes; well-demarcated plague with a thick silvery scale

Please see the Stanford 25 website which has an excellent introduction to the language of dermatology with great photos and videos:


Tinea Pedis (Athlete’s Foot) & other Tinea conditions (corporis, cruris, etc.)

  • Clinical Patterns:
    • Interdigital – flaking epidermis between toes
      • Maceration can occur between the toes. Shows up first between the fourth and fifth toes.
    • Moccasin – Forms a rim around the bottom of the foot
    • Vesicobullous – blister forming
  • Treatment
    • First line:
      • Clotrimazole cream BID x 4 weeks (can buy OTC as Lotrimin)
      • Terbinafine Cream (e.g. Lamasil)
  • Things to avoid!
    • Do not treat something that may be fungal with a topical steroid –> this will cause the rash to increase in size. If you are unsure if it is inflammatory or fungal, opt to treat for 4 weeks with OTC anti-fungals and instruct patient to use a topical steroid if this first line therapy is ineffective



  • Key findings: subungual debris and nail discoloration
  • What tests should be ordered?
    • Fungal culture of subungual debris (textbook answer, although this is not always done clinically)
  • Treatment
    • First line: Oral terbinafine x 3 months
      • After treatment, the nail will take roughly 1 year to “grow out” before it may return to normal.
      • Treatment failure rate: 50%
      • Terbinafine risks: low risk of hepatotoxicity; check baseline LFTs
    • Ciclopirox nail lacquer
      • This is a toenail polish. Must be used daily for 1 year. Treatment success rate is only 11%
    • Second Line
    • Itraconazole
      • Pulse dosing for 3 months: 200mg BID x 7 days during the first week of every month.
      • You must watch out for interactions with other medications: e.g. statins
    • Fluconazole
      • If there is concern for co-infection with mold, it can be useful


Tinea versicolor (pityrosporum yeast)

  • May be hypo or hyperpigmented
  • Treatment:
    • Ketoconazole shampoo – 5 days
    • Selenium sulfide (Selsun Blue)

Stasis dermatitis

  • rash that results from 3rd spaced fluid; due to hemosiderin spilled from RBCs
    • Tx: Triamcinolone; avoid skin, face, groin, armpits
  • Compression wraps “unna boot” -> transition to compression stockings (20-30 mmHg)




  • Candida will involve scrotum; dermatophytes usually doesn’t involve scrotum.
  • Treatment: clotrimazole, nystatin, ketoconazole (not great for dermatophytes)