ABD Cheat Sheet 2026

The 30 highest-yield ABD facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which constellation of findings is diagnostic of Waardenburg syndrome? → Sensorineural deafness, white forelock, heterochromia iridis, and dystopia canthorum
2. A positive Nikolsky sign indicates: → Epidermal detachment with lateral pressure
3. When documenting a patient encounter, the medical record should be: → Accurate, timely, and complete
4. Which HLA allele is most strongly associated with an increased risk of carbamazepine-induced Stevens-Johnson syndrome in Han Chinese patients? → HLA-B*1502
5. A young adult presents with a single large 'herald patch' followed by a christmas-tree distribution of scaly macules. What is the diagnosis? → Pityriasis rosea
6. Extramammary Paget disease of the vulva most often stains positively for which marker? → CK7
7. A pigmented lesion demonstrates nests of melanocytes at both the dermoepidermal junction and within the dermis. This architecture defines which nevus type? → Compound nevus
8. Pautrier microabscesses (intraepidermal collections of atypical lymphocytes) are a diagnostic feature of which condition? → Mycosis fungoides
9. Under Wood's lamp examination, vitiligo-affected skin characteristically shows: → Bright blue-white (chalk-white) fluorescence accentuating depigmentation
10. Fibrofolliculomas, trichodiscomas, and acrochordons with renal tumors and spontaneous pneumothorax define: → Birt-Hogg-Dubé syndrome
11. Which virus is the causative agent of molluscum contagiosum? → Poxvirus
12. Flame figures (eosinophilic material coating collagen) are the histologic hallmark of which condition? → Wells syndrome (eosinophilic cellulitis)
13. The HLA-Cw6 allele shows the strongest genetic association with which dermatologic disease? → Psoriasis
14. A positive hair pull test is defined as extraction of more than how many hairs from a bundle of 50-60 hairs? → 6 hairs
15. Neurofibromatosis type 1 is caused by a mutation in which gene? → NF1 (neurofibromin)
16. Which topical agent is first-line treatment for scabies? → Permethrin 5% cream
17. Which topical antibiotic is combined with benzoyl peroxide to reduce bacterial resistance in acne? → Clindamycin
18. Which malignant melanoma subtype is most common on the palms, soles, and nail beds, particularly in darker-skinned patients? → Acral lentiginous melanoma
19. Which idiopathic photodermatosis is the most common, affecting up to 10-20% of the population in temperate climates? → Polymorphous light eruption (PMLE)
20. The complement pathway activated directly by antigen-antibody complexes begins with which component? → C1
21. Which drug is first-line for dermatitis herpetiformis symptom control? → Dapsone
22. Kligman's formula, the gold standard for melasma treatment, consists of which combination? → Tretinoin + hydroquinone + low-potency topical corticosteroid
23. Which of the following is the defining histopathologic feature used to classify a blistering disease as 'pemphigus'? → Acantholysis leading to an intraepidermal split
24. An adolescent presents with comedones, inflammatory papules, and pustules on the face. What is the first-line topical agent for comedonal acne? → Topical retinoid
25. Immune checkpoint inhibitor-induced vitiligo-like depigmentation in a melanoma patient is generally associated with: → A favorable treatment response
26. What is the initial phase of skin graft survival before revascularization? → Imbibition
27. A patient presents with a tense subepidermal blister and linear IgG along the basement membrane on direct immunofluorescence. What is the diagnosis? → Bullous pemphigoid
28. Hailey-Hailey disease (benign familial pemphigus) is caused by mutations in which gene? → ATP2C1 (hSPCA1)
29. A tender, well-demarcated, raised, bright red facial plaque with a sharp border is characteristic of: → Erysipelas
30. Bilateral vestibular schwannomas are the hallmark of which neurocutaneous disorder? → Neurofibromatosis type 2