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Medical Services

Common Skin Diseases

At Duncan Dermatology, our providers have decades of experience in diagnosing and managing the common skin diseases seen in dermatology, such as acne, rosacea, eczema, psoriasis, vitiligo, hives, rashes, infections, and moles to name a few.  We understand that even the smallest changes in your skin, the development of new growths, and persistent rashes can weigh heavily on your psyche and interfere with daily life.  No problem of yours is too small for us to tackle.  Together we will manage your skin concerns and conditions to help minimize your worries and get you back to living a full life! Call us at (707) 967-0800 to schedule an appointment.


We have multiple modalities to manage acne and rosacea, including:

Complex Skin Diseases

Our team of experienced medical dermatologic providers is skilled at and comfortable with the diagnosis and management of complex dermatology problems, such as autoimmune connective tissue diseases (e.g. cutaneous lupus, dermatomyositis), blistering diseases (e.g. bullous pemphigoid, pemphigus), severe psoriasis, pyoderma gangrenosum, leg ulcers and cutaneous vasculitis.

We are very comfortable at providing second opinions on difficult dermatologic diagnoses and we welcome the opportunity to help you.

Skin Cancer

We take the time to perform total body skin examinations to look for possible precancers (e.g. actinic keratoses) and skin cancers (e.g. basal cell carcinomas, squamous cell carcinomas, melanoma) that might not be apparent to you.  Early detection and treatment are key to the best outcomes.

In addition to finding and treating skin cancers at their earliest stages, we want to help you bring your skin back to its best possible health and actually devise ways to help prevent skin cancers.  Such modalities might include:

  • Field treatments to clear up widespread pre-cancers (actinic keratoses) with modalities such as photodynamic therapy and topical chemotherapeutic and immunologic agents
  • Recommendations for sunscreens and topical antioxidants
  • Discussion of the benefit of oral niacinamide 500 mg twice a day

Pediatric Skin Diseases

We are very comfortable diagnosing and managing skin conditions that affect children, such as rashes, warts, molluscum, atopic dermatitis, growths and infections of the skin, to name a few.

Hair and Nail Disorders

We take a holistic approach to diagnosing and managing hair loss, looking at your entire medical history, recent lab work, medications, and life stressors.  Together we may decide to order additional blood tests to try and determine the cause of your hair loss.  An in-depth discussion of treatment options will ensue.


  • For male and female-pattern hair loss we offer an affordable, prescription topical solution for hair regrowth
  • Alopecia areata, an autoimmune hair loss condition, is often managed with monthly local injections of corticosteroids


Not all abnormalities and discolorations of the nails are due to fungal infections. We are experienced at getting to the bottom of such nail disorders and recommending a treatment plan.  When necessary, we utilize both prescription oral and topical agents for the treatment of fungal nail infections and we offer an affordable topical prescription agent through our office.​

Healthy Skin

Patients commonly ask us how they can make their skin look “better,” “clearer,” or more “vibrant.” Every patient has the potential to achieve healthy skin that glows and we are excited to work with you to achieve this goal.  We employ a multi-modality approach that includes:

  • A complete skin exam to identify and treat any pre-cancerous or cancerous lesions
  • An evaluation of your current skin care regimen to ensure you are using the key ingredients on your skin to prevent and protect it from the environment
  • Recommendations for correcting the signs of aging skin, which might include a combination of prescription agents, quality skin care productslaser treatments or microneedling.
  • Possible referral to our skin care therapist for HydraFacial® MD treatments and/or chemical peels
  • Possible referral to our cosmetic services providers for discussion of injectables

Photodynamic Therapy

Photodynamic therapy (PDT) is a procedure that uses a photosensitizing, topically applied drug (aminolevulinic acid or ALA) plus light therapy (blue light) to target pre-cancerous skin lesions (actinic keratoses), sun damaged skin, and acne. PDT is best used to clear the skin of actinic keratoses when numerous such lesions are present on the face, ears, neck, scalp, chest, arms/hands, or lower legs. Sun damage, fine lines and blotchy discoloration are also improved with this treatment and it has the unique ability to minimize pores and reduce oil glands, effectively treating stubborn acne, rosacea, and even acne scarring.For best results, typically a series of 2-3 treatments, 4-6 weeks apart are necessary.

Prior to your scheduled PDT appointment, you will be given verbal and written instructions on what to do to prepare for the treatment. We may also give you topical medications to use at home to prep the skin for the PDT. We ask that you bring a hat or other appropriate sun-protective clothing to your appointment as your skin will be sensitive to all light for the 48 hours following the treatment. It is also good to bring a book, snack, and music or books-on-tape plus headphones to keep yourself occupied while you wait in our office.

At the time of your appointment a provider will thoroughly cleanse the skin and perform an acetone scrub to prepare the skin for the application of the ALA. Sometimes thicker pre-cancerous lesions will be curetted off to maximize the effect of the PDT. The ALA liquid solution will then be applied to the entire skin area that has been designated for treatment. You will next incubate for about 15 minutes to 3 hours, depending on your condition and the sites to be treated. After this incubation period, your skin will be exposed to the blue light, which will activate the ALA. The amount of light exposure time will also vary depending on the treatment protocol your provider chooses, typically between 16-60 minutes. During the light exposure, you may experience some burning discomfort, which can be lessened by the use of fans. Following the treatment, we will wash off the ALA and apply a thick moisturizer and zinc oxide-based sunscreen.

After the PDT procedure, the skin that has been treated will be extremely light sensitive for 48 hours, until the topical medication has been completely metabolized. Hats and sun-protective clothing, a zinc oxide-based sunscreen, and light avoidance are required to protect the skin during that time. You should expect some redness, peeling, and mild discomfort over the ensuing 3 days.Occasionally there can be a burning discomfort for 24 hours and more prolonged peeling and redness for 1-2 weeks. We will provide you with written instructions on how to take care of your skin at home.

Hereditary Cancer

Dr. Duncan is a member of the St. Helena Hereditary Cancer Consortium. The Hereditary Cancer Consortium is a group of physicians who are specialists in gynecology, internal medicine, gastroenterology, oncology/hematology, dermatology, and breast & reconstruction surgery who have a shared goal of helping patients identify their risks of a hereditary cancer syndrome and helping those who are at higher risk have options to reduce their risk or to actually prevent cancer. This information helps prevent cancer and saves lives for generations to come.

As a patient in our practice, we will work with you to determine if you have such risk factors and make sure you get access to genetic counseling and testing.  A hereditary cancer screening questionnaire is available to help identify characteristics that suggest a hereditary cancer risk. 

If you have already been identified as having a familial cancer syndrome or as having an elevated personal risk for melanoma, we will follow you closely with regular total body skin examinations.

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Other Services

Our highly trained providers offer the latest procedures and treatments to help you look your best.

We specialize in science-based therapies using the highest quality skin care products to help create more youthful and healthier skin.

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