Phototherapy: UVB 290-320, UVA 320-400,  can be used to treat skin diseases, such as psoriasis, can cause burns, cancer, and aging


Potassium hydroxide (KOH) mount: can diagnose dermatophyte infection via scraping of the edge of a scaling lesion and placing a drop or two of KOH w dimethylsulfoxide (DMSO) on the slide, blot, examine w low illumination, low power, looking for hyphae, can be difficult to find, can also use to diagnose candidal infection if you see hyphae/pseudohyphae 


Tzanck: can diagnose herpetic infection via scrapings from vesicular lesions, can see multinucleated giant cells, for herpetic viral infections can also do immunofluorescent staining


Scabies: can do a scraping of a suspected burrow and visualize the mite 


Cultures: scrapings, swabs, biopsies can be sent to assess for bacterial, viral, or fungal growth 


Biopsy: punch,  shave


Patch tests: used in diagnosing allergic contact dermatitis, patches left on the skin for 2 days 


Immunofluorescence: can detect autoantibodies to diagnose blistering disorders 


Mohs micrographic surgery: used for basal and squamous cell carcinomas of the skin,  layers are removed and examined one at a time to ensure all of the margins of a tumor are removed


Excision: gets tissue sample for study, can remove lesions, length 3x the width, use sutures to close 


Electrodessication and curettage: for removal of carcinomas, remove w curette and tx w electrode to destroy remaining cancerous cells


Cryosurgery: uses super cold liquid nitrogen, often used to tx warts or other common lesions such as seborrheic keratoses


With all surgeries and invasive procedures, make sure to get informed consent, discuss complications (neural damage, scarring, infection), discuss alternatives, and educate your patient on their condition! 


References: AAD Basic Dermatology Curriculum, Dermatology by Bolognia et. al., Lookingbill and Mark's Principles of Dermatology, First Aid USMLE Step 1 2020, First Aid USMLE Step 2 CK