Dermatology Deep Dive: Skin Conditions Every FNP Must Know for Boards
Clinical High-Yield · 11 min read · April 28, 2026
Dermatology is one of the most visual specialties in medicine — which creates a unique challenge for a written board exam. The boards cannot show you a photograph (at least not on the AANP and ANCC written exams), so they describe lesions in precise clinical language. Your job is to translate that description into a diagnosis. Here is the complete high-yield guide.
Primary Lesion Types: The Vocabulary You Must Know
The boards use specific dermatological terminology to describe lesions. If you do not know this vocabulary, you cannot answer dermatology questions correctly — regardless of how well you know the diseases.
Macule: Flat, non-palpable color change, <1 cm. Examples: freckle, café-au-lait spot, petechiae.
Patch: Flat, non-palpable color change, >1 cm. Examples: vitiligo, port-wine stain.
Papule: Elevated, palpable, solid lesion, <1 cm. Examples: wart, molluscum contagiosum, acne (closed comedo).
Plaque: Elevated, palpable, flat-topped solid lesion, >1 cm. Examples: psoriasis, lichen planus.
Nodule: Elevated, palpable, solid lesion, 1–2 cm, deeper than a papule. Examples: lipoma, dermatofibroma, rheumatoid nodule.
Vesicle: Elevated, fluid-filled lesion, <1 cm. Examples: herpes simplex, varicella, contact dermatitis.
Bulla: Elevated, fluid-filled lesion, >1 cm. Examples: bullous pemphigoid, pemphigus vulgaris, second-degree burn.
Pustule: Elevated, pus-filled lesion. Examples: acne (pustular), folliculitis, impetigo.
Wheal (hive): Elevated, edematous, transient lesion with central pallor and surrounding erythema. Examples: urticaria, insect bite reaction.
Cyst: Elevated, encapsulated, fluid or semi-solid filled lesion. Examples: epidermoid cyst, pilar cyst.
Inflammatory Skin Conditions: The Board Favorites
Psoriasis: Chronic, autoimmune, inflammatory skin condition. Classic presentation: well-demarcated, erythematous plaques with silver-white scale, located on extensor surfaces (elbows, knees), scalp, and lower back. The Auspitz sign (pinpoint bleeding when scale is removed) is pathognomonic. Nail findings: pitting, onycholysis, "oil drop" sign. Associated with psoriatic arthritis (asymmetric oligoarthritis, DIP involvement, sausage digits). Treatment: mild-moderate: topical corticosteroids (first-line), vitamin D analogs (calcipotriene), topical retinoids. Moderate-severe: phototherapy (UVB), methotrexate, cyclosporine, biologics (TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors).
Atopic Dermatitis (Eczema): Chronic, relapsing inflammatory skin condition associated with atopy (asthma, allergic rhinitis). Presentation varies by age: infants — cheeks, scalp, extensor surfaces; children and adults — flexural surfaces (antecubital and popliteal fossae), neck. Intensely pruritic. Skin is dry, lichenified (thickened with accentuated skin lines from chronic scratching). Treatment: moisturizers (cornerstone of management), topical corticosteroids (first-line for flares), topical calcineurin inhibitors (tacrolimus, pimecrolimus — second-line, avoid in immunocompromised), dupilumab (biologic for moderate-severe disease).
Contact Dermatitis: Two types — allergic (type IV hypersensitivity, delayed 48–72 hours after exposure) and irritant (direct damage from a chemical, no sensitization required). Presentation: erythema, vesicles, weeping, pruritus in the distribution of the offending agent. Classic allergens: nickel (jewelry), poison ivy/oak/sumac (urushiol), latex, fragrances. Diagnosis: patch testing for allergic contact dermatitis. Treatment: identify and remove the offending agent; topical corticosteroids for mild-moderate disease; oral corticosteroids for severe or widespread disease.
Board Pearl: The boards love to test the distribution of contact dermatitis. Poison ivy causes linear streaks of vesicles (from dragging the plant across the skin). Nickel allergy causes dermatitis at the site of jewelry contact (earlobes, wrist, umbilicus from belt buckle). The distribution tells you the cause.
Acne Vulgaris: Classification and Treatment
Acne is the most common skin condition in the United States, and the boards test it at every level of severity.
Classification:
- Comedonal acne: open comedones (blackheads) and closed comedones (whiteheads) — no inflammation
- Mild-moderate inflammatory acne: papules and pustules
- Severe inflammatory acne: nodules and cysts (nodulocystic acne)
Treatment by severity:
- Comedonal: topical retinoids (tretinoin, adapalene) — first-line
- Mild-moderate inflammatory: topical retinoid + topical antibiotic (clindamycin or erythromycin) ± benzoyl peroxide (reduces antibiotic resistance)
- Moderate-severe: oral antibiotics (doxycycline, minocycline) + topical retinoid + benzoyl peroxide
- Severe nodulocystic: isotretinoin (Accutane) — the most effective treatment, but requires iPLEDGE program enrollment due to teratogenicity. Monthly pregnancy tests and two forms of contraception required for women of childbearing potential.
- Women with hormonal acne: oral contraceptives (estrogen-progestin) or spironolactone
Skin Cancer: The Three Types You Must Know
Basal Cell Carcinoma (BCC): The most common skin cancer. Caused by UV radiation. Classic presentation: pearly, translucent papule with rolled borders and telangiectasias on sun-exposed skin (face, scalp, neck). Rarely metastasizes. Treatment: surgical excision (Mohs surgery for high-risk locations), topical imiquimod or 5-fluorouracil for superficial BCC.
Squamous Cell Carcinoma (SCC): The second most common skin cancer. Caused by UV radiation, chronic inflammation, HPV (for mucosal SCC). Arises from actinic keratoses (AKs — rough, scaly patches on sun-exposed skin that are precancerous). Classic presentation: firm, erythematous papule or plaque with scale or ulceration. Can metastasize (especially on the lip, ear, and in immunocompromised patients). Treatment: surgical excision.
Melanoma: The most dangerous skin cancer — responsible for the majority of skin cancer deaths. The ABCDE criteria: Asymmetry, Border irregularity, Color variation (multiple colors within one lesion), Diameter >6 mm, Evolution (changing over time). Risk factors: UV exposure, fair skin, family history, atypical moles (dysplastic nevi), immunosuppression. Any suspicious lesion requires excisional biopsy (not shave biopsy — you need the full depth for Breslow thickness measurement). Treatment: surgical excision with wide margins; sentinel lymph node biopsy for lesions >1 mm thick.
Actinic Keratosis (AK): A precancerous lesion caused by chronic UV exposure. Presents as rough, scaly, erythematous patches on sun-exposed skin. Risk of progression to SCC is ~1% per lesion per year. Treatment: cryotherapy (liquid nitrogen), topical 5-fluorouracil, topical imiquimod, photodynamic therapy.
Common Rashes: The Boards' Favorite Presentations
Tinea infections: Caused by dermatophytes. Tinea corporis (ringworm) — annular plaque with central clearing and raised, scaly border. Tinea pedis (athlete's foot) — interdigital maceration, scaling, pruritus. Tinea capitis (scalp) — scaling, hair loss, kerion (boggy, inflammatory mass). Tinea versicolor (Malassezia furfur) — hypopigmented or hyperpigmented macules on the trunk, worse in summer. KOH preparation shows hyphae and spores ("spaghetti and meatballs" for tinea versicolor). Treatment: topical antifungals (clotrimazole, terbinafine) for most; oral antifungals (griseofulvin, terbinafine) for tinea capitis.
Scabies: Caused by Sarcoptes scabiei mite. Intensely pruritic, worse at night. Classic distribution: finger webs, wrists, axillae, genitalia, areolae. Burrows (linear tracks) are pathognomonic. Treatment: permethrin 5% cream (first-line), applied from neck to toes, left on 8–14 hours, then washed off. Treat all household contacts simultaneously. Wash all clothing and bedding in hot water.
Rosacea: Chronic inflammatory condition affecting the central face. Four subtypes: erythematotelangiectatic (flushing, redness, telangiectasias), papulopustular (acne-like papules and pustules without comedones), phymatous (skin thickening, rhinophyma), ocular (eye involvement). Triggers: sun, heat, alcohol, spicy food, stress. Treatment: topical metronidazole or azelaic acid (first-line), topical ivermectin (for papulopustular subtype), oral doxycycline (for moderate-severe papulopustular), laser therapy for telangiectasias.
The Bottom Line
Dermatology on the FNP boards rewards knowing your lesion vocabulary, your inflammatory skin conditions (psoriasis vs. eczema vs. contact dermatitis), your acne treatment ladder, and your skin cancer recognition (BCC vs. SCC vs. melanoma ABCDE criteria). Know your tinea infections and their KOH findings. Know scabies distribution and treatment. Master these and dermatology becomes one of your most reliable sections.
→ Explore the FNP Board Review Book — every dermatology topic covered with board-focused clinical pearls and practice questions.