CCFP priority topic 90 of 105
Skin Disorder on the CCFP exam
7 key features, the mistakes that cost marks, and a practice question.
Checked by a Canadian family physician, MD, CCFP. Updated October 22, 2026.
What the exam tests
Key features
The CFPC’s 7 key features for Skin Disorder. Each one below has how the exam asks it, the common mistakes and the approach.
Practice question
Try one before you read
A real case from the bank, in the new short-menu format. Answer it first. Then read the key features.
Key feature 1 of 7
Not getting better
When a rash or acne keeps failing treatment, check the label and rethink the plan.
CFPC skill Clinical reasoningPhase Hypothesis generation, diagnosis, treatment, investigationSources Choosing Wisely Canada, Health Canada
On the exam
Scarring acne still active after months of an antibiotic pill and a gel. Expect one best answer for the next drug.
Pick the next drug and its safety steps.
Common mistakes
Switching to minocycline, or overlapping doxycycline with isotretinoin. Another antibiotic prolongs a failed course. Any tetracycline with isotretinoin can raise pressure inside the skull.
Approach
- A rash that fails treatment: question the label first. Toe-web or groin “eczema” that spreads on steroid cream may be a fungal infection.
- Confirm a fungal infection with a skin scraping before you treat it. Do not routinely use steroid and antifungal combination creams: they work less well and can thin the skin.
- Thick, crumbly nails: confirm fungus with a lab test before an oral antifungal. Only about half of abnormal nails are fungal.
- Acne on an oral antibiotic: judge the response at 3 months. Always pair the pill with topical benzoyl peroxide or a topical retinoid.
- Not working at 3 months: change course. Options are a retinoid, or in females spironolactone or a combined birth control pill.
- Isotretinoin is for severe nodular or inflamed acne that standard first-line treatment has not controlled. Stop every tetracycline before the first dose.
- Screen for depression before isotretinoin and during it. Stop the drug if low mood starts or gets worse.
| What to do | Why | |
|---|---|---|
| Contraception | Effective contraception with no break, from 1 month before the first dose until 1 month after the last. Two reliable methods together are recommended. | It causes severe birth defects, even after short exposure |
| Pregnancy tests | A negative test before each 30-day prescription, and 1 month after stopping | Prescriptions for women who could become pregnant are limited to 30 days |
| Blood tests | Before starting: fasting lipids, liver and kidney tests, blood sugar. Recheck triglycerides and alanine aminotransferase (ALT) at peak dose. | Choosing Wisely: routine blood counts are not needed in a healthy patient. The product monograph still lists a baseline count. |
| Tetracyclines | Stop before the first dose, at any dose | Together they can raise pressure inside the skull |
| Mood | Screen before starting and at follow-up | Depression and suicide have been reported |
Key feature 2 of 7
Benign or serious
Tell a harmless skin lesion from a dangerous one by looking closely and taking tissue.
CFPC skill Selectivity, clinical reasoningPhase Physical, investigation
On the exam
A dark mole on the back that has changed shape. Expect one best answer for the next step.
Pick the next step for the lesion.
Common mistakes
Reassuring because the mole is one of many, or removing it without sending tissue to the lab. A melanoma then goes undiagnosed.
Approach
- Look for an uneven shape, a ragged border, mixed colours, a large size, and above all change over time.
- Compare it with the patient's other moles. One that looks different from the rest is suspect.
- Feel the lymph nodes that drain the area.
- Blisters that break easily, with mouth sores that do not heal, suggest pemphigus, an immune blistering disease.
- A scaly patch called eczema or psoriasis that fails treatment for months in an older adult can be lymphoma of the skin.
Key feature 3 of 7
Skin as a clue
A rash can be the first sign of a disease elsewhere in the body, so look for one.
CFPC skill Clinical reasoningPhase Hypothesis generation, diagnosisSources Health Canada
On the exam
Rash and fever in a child six weeks into lamotrigine for seizures. Expect a short menu (pick several from a list) of next steps.
Pick the questions and steps that confirm a drug reaction.
Common mistakes
Calling rash and fever a virus in a child on a new antiseizure drug. No one can predict which drug rash will become life-threatening.
Approach
- Take a full drug history: prescribed, over-the-counter and herbal, with the start date of each.
- On lamotrigine, nearly all rashes start 2 to 8 weeks after the first dose. Stop it at once unless the rash is clearly not from the drug.
- In a child, a lamotrigine rash with fever can look like an infection. Think of the drug in the first 8 weeks.
- Ask about joint pain, fevers, mouth ulcers, breathing, nosebleeds or sinus trouble, and changes in the urine.
- Raised purple spots that do not fade when pressed suggest inflamed blood vessels (vasculitis). Look for signs that the kidneys, lungs or joints are involved.
- A red rash over the cheeks and nose, with joint pain and mouth ulcers, suggests lupus.
Key feature 4 of 7
Look everywhere
Examine the whole skin surface, including places patients never show you.
CFPC skill Clinical reasoningPhase Physical
On the exam
An adult worried about one mole on the arm. Expect a short menu (pick several from a list) of areas to examine.
Pick the areas to examine.
Common mistakes
Examining only the mole the patient points to. Serious lesions hide on the scalp, soles, nails and genitals, where patients cannot see them.
Approach
- Gown the patient and look at all the skin in good light.
- Part the hair to check the scalp. Look at the back of the neck and behind the ears.
- Check every nail. A new dark streak in a single nail needs a closer look.
- Look in the mouth: gums, tongue and inside the cheeks.
- Check the soles, between the toes, and the genital and anal skin.
- Explain why you are looking, and offer a chaperone for the genital exam.
Key feature 5 of 7
Skin emergencies
Recognize skin conditions that can kill, and start treatment without delay.
CFPC skill SelectivityPhase Diagnosis, hypothesis generationSources Health Canada, Choosing Wisely Canada, Canadian Paediatric Society 2026
On the exam
Painful peeling skin and mouth sores, weeks after starting a new drug. Expect one best answer for the first step.
Pick the first step.
Common mistakes
A routine dermatology referral, or a steroid cream while the drug keeps going. The first step is to stop the likely drug.
Approach
- Blisters or peeling skin with sores in the mouth, eyes or genitals after a new drug: think of Stevens-Johnson syndrome, a severe drug reaction. Stop the drug.
- Pain far worse than the skin looks, fast-spreading redness, dead skin, or crackling under the skin: think of a severe deep infection.
- A necrotizing (tissue-destroying) infection needs an urgent surgical consult to cut away the dead tissue.
- Both lower legs red and swollen: think of stasis dermatitis, skin inflammation from poor vein drainage, before cellulitis. Do not routinely prescribe antibiotics.
| Emergency | Clues | First move |
|---|---|---|
| Stevens-Johnson syndrome | Peeling or blistering skin, sores in the mouth, eyes or genitals, a new drug | Stop the drug. |
| Deep tissue-destroying infection | Pain worse than the skin looks, fast-spreading redness, dead skin, crackling | Urgent surgical consult |
| Not an emergency: both legs red | Both lower legs, itch, brown staining, no fever | Likely stasis dermatitis. No routine antibiotics. |
Key feature 6 of 7
High-risk skin
Check the skin of high-risk patients routinely, and treat small breaks early.
CFPC skill Clinical reasoning, selectivityPhase Physical, treatmentSources Choosing Wisely Canada
On the exam
An older woman with diabetes, poor circulation and poor eyesight comes for a diabetes review. Expect a short menu (pick several from a list) of exam steps.
Pick the exam steps that change her care.
Common mistakes
Checking her blood pressure and weight but leaving her shoes and socks on. Her soles and toe webs are where harm starts, and she cannot see them.
Approach
- Take off shoes and socks and look: soles, heels, and between the toes.
- Check feeling and the foot pulses.
- In bed- or chair-bound patients, check the pressure points: tailbone, hips and heels.
- White, soggy, split skin between the toes is likely fungal. Confirm it with a skin scraping.
- Treat it with a topical antifungal, not a steroid and antifungal combination cream.
- A small crack, blister or sore on this foot gets treated and rechecked early. Do not wait for it to look infected.
- Teach her not to walk barefoot or soak her feet. If she cannot see her soles, someone else checks them every day.
Key feature 7 of 7
Life impact
Ask how a skin condition is affecting the patient's mood, friends, school or work.
CFPC skill Patient-centred approachPhase Treatment, historySources Health Canada
On the exam
A withdrawn 16-year-old girl with scarring acne. Expect a short menu (pick several from a list) of questions to ask.
Pick the questions that show the impact.
Common mistakes
Asking about diet, washing, makeup or screen time. None shows how the acne is affecting her, and none changes the plan for scarring acne.
Approach
- See her alone for part of the visit.
- Ask what she avoids because of her skin: school, sports, photos, friends, dating.
- Ask directly about teasing and bullying, in person and online.
- Screen for low mood and thoughts of suicide, before isotretinoin and during it.
- Severity and impact are different things. Counting spots measures one, not the other.
- In psoriasis, ask about work, sleep, sex and relationships too.
Flashcards
Answer it first, then check.
KF 1Acne is no better after 3 months of an oral antibiotic. What now?
Change course: a retinoid, or in females spironolactone or a combined birth control pill. Source: Choosing Wisely Canada
KF 1Doxycycline is failing and isotretinoin is next. Can the two overlap?
No. Tetracyclines are contraindicated with isotretinoin. Together they can raise pressure inside the skull. Source: Health Canada
KF 1When must contraception start before isotretinoin, and how many methods?
One month before the first dose, with no break. Two reliable methods together are recommended. Source: Health Canada
KF 1Toe-web “eczema” is worse after weeks of steroid cream. What is the first test?
A skin scraping for fungus. Then treat with a topical antifungal, not a combination cream. Source: Choosing Wisely Canada
KF 3A child has rash and fever five weeks into lamotrigine. What do you do?
Think of a drug reaction. Stop lamotrigine unless the rash is clearly not from the drug. Source: Health Canada
KF 5Both lower legs are red and swollen, with no fever. Cellulitis?
Often not. Stasis dermatitis usually affects both legs. Do not routinely prescribe antibiotics. Source: Choosing Wisely Canada
KF 2The patient has many moles, and one looks different from the rest. Is that reassuring?
No. A mole unlike the patient's others is suspect, even among many. Check it closely for change.
FAQ
Which guideline does the exam use for skin problems?
No single Canadian guideline covers this topic. Know the Canadian Dermatology Association's Choosing Wisely list and the isotretinoin safety rules. The rest is careful history, a full skin exam and sound reasoning.
Pemphigus or pemphigoid: how do I tell them apart?
Pemphigus gives fragile blisters that break into raw sores, often starting in the mouth. Pemphigoid gives tense, itchy blisters, mostly in older adults. Both are immune blistering diseases.
Do family doctors prescribe isotretinoin?
Only those who know how to use it. The product monograph limits it to doctors experienced with oral retinoids and asks every patient to sign a consent. Either way, know the safety rules.
Who counts as high risk for routine skin checks?
People with diabetes, poor circulation in the legs, or who spend most of the day in bed or a chair. Their skin breaks easily, heals slowly, and small sores may not hurt.
Sources
Written from the CFPC Assessment Objectives and Canadian guidelines first. Checked by a Canadian family physician, MD, CCFP.
Last reviewed October 22, 2026For exam study. Not advice for a patient in front of you.
- Assessment Objectives for Certification in Family Medicine, 2nd editionCollege of Family Physicians of Canada · 2020
- Choosing Wisely recommendationsChoosing Wisely Canada
- Drug Product DatabaseHealth Canada
- Management of community-associated bacterial skin and soft tissue infections in children and prevention of recurrenceCanadian Paediatric Society · 2026