12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity

ABIM Internal Medicine Exam

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1 Chapter 0: The ABIM Exam, Blueprint & Study Strategy

0.1 Exam Format, Question Types & the 2026 Blueprint 0.2 Eligibility, Registration, Fees & Exam-Day Logistics 0.3 Scoring, the Passing Standard & Score Reports 0.4 Building a Blueprint-Weighted Study Plan

2 Chapter 1: Cardiovascular Disease (14% of Exam)

1.1 Ischemic Heart Disease & Acute Coronary Syndromes 1.2 Antithrombotic Therapy, Secondary Prevention & Mechanical Complications of MI 1.3 Atrial Fibrillation, Atrial Flutter & Stroke Prevention 1.4 Supraventricular Tachycardias, Ventricular Arrhythmias & Bradycardias 1.5 Heart Failure: Classification, Staging & Guideline-Directed Medical Therapy 1.6 Device Therapy, HFpEF & the Cardiomyopathies 1.7 Valvular Heart Disease & Endocarditis Prophylaxis 1.8 Pericardial Disease & Acute Aortic Syndromes 1.9 Hypertension: Classification, Diagnosis & Secondary Causes 1.10 Hypertensive Crises & Dyslipidemia 1.11 Adult Congenital Heart Disease & Coarctation of the Aorta 1.12 Syncope: Reflex, Orthostatic & Cardiac Causes 1.13 Cardiac Physical Examination, Murmurs & Antithrombotic Selection

3 Chapter 2: Endocrinology, Diabetes & Metabolism (9% of Exam)

2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy 2.2 Insulin Therapy, Hyperglycemic Emergencies & Chronic Complications 2.3 Thyroid Function Testing & Hypothyroidism 2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules 2.5 Adrenal & Pituitary Disorders 2.6 Hypercalcemia, Hypocalcemia & Disorders of Mineral Metabolism 2.7 Osteoporosis & Paget Disease of Bone 2.8 Ovarian, Testicular & Reproductive Endocrine Disorders 2.9 Hypoglycemia, Endocrine Tumors, Polyglandular Syndromes & Severe Hypertriglyceridemia

4 Chapter 3: Gastroenterology & Hepatology (9% of Exam)

3.1 Esophageal Disease 3.2 Stomach & Duodenal Disease and Gastrointestinal Hemorrhage 3.3 Inflammatory Bowel Disease 3.4 Celiac Disease & Irritable Bowel Syndrome 3.5 Diverticular Disease & Colorectal Cancer Screening 3.6 Viral Hepatitis, Steatotic & Alcohol-Associated Liver Disease 3.7 Cirrhosis & the Complications of Portal Hypertension 3.8 Acute Pancreatitis 3.9 Chronic Pancreatitis & Biliary Tract Disease 3.10 Inherited, Autoimmune & Drug-Induced Liver Disease 3.11 Small Intestinal Disease, Ischemia & Gastrointestinal Complications of HIV

5 Chapter 4: Infectious Disease (9% of Exam)

4.1 Lower Respiratory Tract Infections & Sepsis Syndromes 4.2 Viral Respiratory Pathogens & Tuberculosis 4.3 Central Nervous System Infections 4.4 Skin, Soft Tissue, Bone & Joint Infections 4.5 Infective Endocarditis & Cardiovascular Infection 4.6 Clostridioides difficile & Catheter-Related Bloodstream Infection 4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention 4.8 Opportunistic Infections & Sexually Transmitted Infections 4.9 Fever of Unknown Origin, Neutropenic Fever & Toxic Shock 4.10 Travel-Related Illness, Vector-Borne Disease & Outbreaks 4.11 Infection Prevention, Nosocomial Infection & Postexposure Prophylaxis 4.12 Rheumatic Fever, Poststreptococcal Disease, Enteric & Hepatic Infections

6 Chapter 5: Pulmonary Disease (9% of Exam)

5.1 COPD: Diagnosis, GOLD Classification & Initial Pharmacotherapy 5.2 Interventions That Reduce COPD Mortality & Exacerbation Management 5.3 Asthma: Diagnosis, Stepwise Therapy & Status Asthmaticus 5.4 Interstitial Lung Disease & Idiopathic Pulmonary Fibrosis 5.5 Sarcoidosis, Hypersensitivity Pneumonitis & Occupational Lung Disease 5.6 Pulmonary Embolism: Diagnosis, Risk Stratification & Anticoagulation 5.7 Pulmonary Hypertension & Sleep-Disordered Breathing 5.8 Acute Respiratory Distress Syndrome & Mechanical Ventilation 5.9 Pleural Disease, Empyema & Pneumothorax 5.10 Bronchiectasis, Cystic Fibrosis & Restrictive Lung Disease 5.11 Evaluation of Cough, Dyspnea, Hemoptysis & the Solitary Pulmonary Nodule

7 Chapter 6: Rheumatology & Orthopedics (9% of Exam)

6.1 Rheumatoid Arthritis: Diagnosis & Systemic Manifestations 6.2 Antirheumatic Pharmacotherapy & the Spondyloarthropathies 6.3 Gout: Pathophysiology & Acute Management 6.4 Urate-Lowering Therapy & Calcium Pyrophosphate Deposition Disease 6.5 Osteoarthritis 6.6 Systemic Lupus Erythematosus 6.7 Systemic Sclerosis, Sjogren Syndrome & Inflammatory Myopathies 6.8 The Vasculitides 6.9 Regional Musculoskeletal Syndromes, Back Pain & Sports Injuries 6.10 Other Primary Rheumatic Disorders & Mixed Connective Tissue Disease 6.11 Osteonecrosis & Metabolic Bone Disease

8 Chapter 7: Hematology (6% of Exam)

7.1 Approach to Anemia & the Microcytic Anemias 7.2 Macrocytic, Normocytic & Hemolytic Anemias 7.3 Hemoglobinopathies, Thalassemias & Paroxysmal Nocturnal Hemoglobinuria 7.4 Platelet Disorders, Thrombocytopenia & the Bleeding Patient 7.5 Coagulation Factor Disorders, Thrombophilia & Anticoagulant Reversal 7.6 Acute Leukemias, Chronic Leukemias & Myeloproliferative Neoplasms 7.7 Lymphomas & Plasma Cell Disorders 7.8 Myelodysplastic Syndrome, Myeloproliferative Neoplasms & Porphyria 7.9 Transfusion Medicine & Late Complications of Transplantation

9 Chapter 8: Medical Oncology (6% of Exam)

8.1 Breast, Lung, Colorectal & Prostate Cancer 8.2 Oncologic Emergencies 8.3 Genitourinary & Gynecologic Malignancies 8.4 Head and Neck, Bone & Soft Tissue Cancer and Cancer of Unknown Primary 8.5 Complications of Cancer & Its Treatment 8.6 Cancer Prevention, Survivorship & Psychosocial Care

10 Chapter 9: Nephrology & Urology (6% of Exam)

9.1 Acute Kidney Injury: Staging, Etiology & Urine Microscopy 9.2 Glomerular Disorders & Nephrotic Syndrome 9.3 Nephritic Syndromes, RPGN & Indications for Renal Replacement Therapy 9.4 Chronic Kidney Disease: Staging & Progression Retardation 9.5 Complications of Chronic Kidney Disease: Anemia, CKD-MBD & Acidosis 9.6 Hyponatremia, Hypernatremia & Water Balance 9.7 Potassium Disorders & Systematic Acid-Base Analysis 9.8 Renal Tubular Acidosis & Nephrolithiasis 9.9 Prostate Disorders, Urinary Incontinence & Other Urologic Conditions 9.10 Cystic Kidney Disease, Obstructive Uropathy, Tubulointerstitial Disease & Hematuria

11 Chapter 10: Neurology (4% of Exam)

10.1 Acute Ischemic Stroke: Syndromes & Reperfusion 10.2 Transient Ischemic Attack, Secondary Prevention & Hemorrhagic Stroke 10.3 Headache & Facial Pain 10.4 Seizures, Epilepsy & Movement Disorders 10.5 Multiple Sclerosis & Neuromuscular Junction Disorders 10.6 Motor Neuron Disease & Acute Peripheral Neuropathy 10.7 Cranial Neuropathies & Neuro-Ophthalmology 10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders

12 Chapter 11: Psychiatry & Behavioral Health (4% of Exam)

11.1 Major Depressive Disorder & Medical Mimics 11.2 Antidepressant Pharmacotherapy & Treatment-Resistant Depression 11.3 Bipolar Disorder, Mood Stabilizers & Lithium Toxicity 11.4 Anxiety, Stress-Related & Obsessive-Compulsive Disorders 11.5 Alcohol Use Disorder & Withdrawal 11.6 Pharmacotherapy for Alcohol & Opioid Use Disorder 11.7 Toxidromes, Psychiatric Emergencies & Suicide Risk Assessment 11.8 Psychotic, Somatic Symptom, Factitious & Personality Disorders 11.9 Eating Disorders, Sleep Disorders & Sexual Health

13 Chapter 12: Dermatology (3% of Exam)

12.1 Dermatitis, Papulosquamous & Inflammatory Dermatoses 12.2 Acne, Rosacea & Cutaneous Infections 12.3 Herpes Zoster & Autoimmune Blistering Diseases 12.4 Nodules, Tumors & Cutaneous Oncology 12.5 Dermatologic Emergencies & Severe Cutaneous Adverse Reactions 12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity 12.7 Vascular Dermatoses, Environmental Injury & Cutaneous Signs of Systemic Disease

14 Chapter 13: Obstetrics & Gynecology / Women's Health (3% of Exam)

13.1 Contraception, Preconception Care & Teratogenicity 13.2 Hypertensive Disorders of Pregnancy & Gestational Diabetes 13.3 Thyroid Disease & Venous Thromboembolism in Pregnancy 13.4 Menopause & Menopausal Hormone Therapy 13.5 Abnormal Uterine Bleeding, Endometrial Disease & Gynecologic Cancer Screening 13.6 Breast Disorders & Diseases of the Vulva and Vagina 13.7 Menstrual Disorders, Fibroids, Endometriosis & Early Pregnancy Complications

15 Chapter 14: Geriatric Syndromes (3% of Exam)

14.1 Comprehensive Geriatric Assessment & Frailty 14.2 Falls, Gait Assessment & Polypharmacy 14.3 Urinary Incontinence & Pressure Injuries in Older Adults 14.4 Mild Cognitive Impairment, Dementia & Its Subtypes 14.5 Delirium & the Pharmacotherapy of Cognitive Disorders 14.6 Palliative Care, Hospice & Advance Care Planning 14.7 Chronic Wounds, Nutrition, Swallowing, Constipation & Hip Fracture 14.8 Sensory Impairment, Dizziness, Elder Mistreatment & Care Settings

16 Chapter 15: Allergy & Immunology (2% of Exam)

15.1 Anaphylaxis: Recognition & Emergency Management 15.2 Urticaria & Angioedema 15.3 Drug Allergy, Desensitization & Adult Immunodeficiency 15.4 Food Allergy, Insect Venom Hypersensitivity, Serum Sickness & Contrast Reactions 15.5 Rhinitis, Conjunctivitis, Eosinophilic & Mast Cell Disorders

17 Chapter 16: Preventive Medicine, Immunization & Clinical Epidemiology

16.1 The USPSTF Framework & Evidence-Based Cancer Screening 16.2 Cardiovascular & Metabolic Screening and Primary Prevention 16.3 Adult Immunization & Vaccines in Special Populations 16.4 Clinical Epidemiology, Biostatistics & Study Design

18 Chapter 17: Miscellaneous - Ethics, Patient Safety & Quality Improvement (2% of Exam)

17.1 Principles of Bioethics & Decisional Capacity 17.2 Informed Consent, Treatment Refusal & Special Scenarios 17.3 Surrogate Decision-Making, Advance Directives & Confidentiality 17.4 Patient Safety Science, Medical Error & Diagnostic Reasoning 17.5 Quality Improvement Methods, Health Disparities & Health Equity

19 Chapter 18: Perioperative Medicine & Medical Consultation

18.1 Preoperative Cardiovascular Risk Assessment 18.2 Preoperative Pulmonary Risk & Perioperative Medication Management 18.3 Perioperative Anticoagulation, Bridging & Postoperative Complications

20 Chapter 19: Ophthalmology (1% of Exam)

19.1 The Acute Red Eye & Ophthalmic Emergencies 19.2 Painless Vision Loss & Chronic Ophthalmic Disease 19.3 Uveitis, Scleritis & Orbital Disease

21 Chapter 20: Otolaryngology & Dental Medicine (1% of Exam)

20.1 Dizziness, Vertigo & Epistaxis 20.2 Ear Disorders, Hearing Loss & Upper Respiratory Infections 20.3 Oral Cavity, Salivary Gland, Laryngeal & Taste and Smell Disorders

12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity

Key Takeaways Explain This Topic AI

Pigment disorders, alopecia, disorders of the nails and photosensitivity dermatoses are four separate named blueprint subsections.

Vitiligo is associated with autoimmune thyroid disease, type 1 diabetes, pernicious anemia and Addison disease.

Sudden extensive acanthosis nigricans in an older adult suggests underlying malignancy, most often gastric adenocarcinoma.

Telogen effluvium follows a physiologic stressor by two to three months and produces diffuse non-scarring shedding that recovers spontaneously.

Porphyria cutanea tarda causes painless blistering of sun-exposed skin and is associated with hepatitis C, HIV, alcohol, estrogen and iron overload.

Last updated: August 2026

• 1. Pigment Disorders
• Vitiligo

Autoimmune destruction of melanocytes producing sharply demarcated, completely depigmented macules and patches , often symmetric and favoring the face, hands, and periorificial and acral sites. Depigmentation is chalk-white and accentuated on Wood lamp examination, distinguishing it from the merely hypopigmented lesions of tinea versicolor or post-inflammatory change.

The exam value is the association list. Vitiligo is a marker of autoimmune diathesis:

• Autoimmune thyroid disease — the most frequent association; check thyroid-stimulating hormone
• Type 1 diabetes mellitus
• Pernicious anemia
• Addison disease
• Alopecia areata

Treatment includes topical corticosteroids and calcineurin inhibitors, phototherapy, and newer JAK inhibitor topicals; sun protection is essential because depigmented skin burns readily.

Melasma

Symmetric brown patches on the malar cheeks, forehead and upper lip, driven by estrogen and ultraviolet exposure — hence pregnancy (chloasma, the mask of pregnancy) and combined oral contraceptives. Treatment is rigorous photoprotection , hydroquinone, retinoids and removal of the hormonal trigger. It recurs readily with sun exposure.

Acanthosis nigricans

Velvety, hyperpigmented thickening of intertriginous skin — neck, axillae, groin — often with skin tags.

• Pattern Implication
• Gradual, obesity-associated Insulin resistance — the common form; screen for diabetes
• Drug-induced Nicotinic acid, systemic corticosteroids, insulin, oral contraceptives
• Sudden, extensive, with mucosal or palmar involvement Malignancy , most often gastric adenocarcinoma

Rapid-onset, widespread acanthosis nigricans in a non-obese adult, especially with weight loss or involvement of the palms (tripe palms) or oral mucosa, warrants a malignancy evaluation.

Xeroderma pigmentosum

An enumerated topic: an inherited defect in nucleotide excision repair causing extreme ultraviolet sensitivity, severe photodamage from childhood and markedly elevated rates of skin cancer at a young age . Management is absolute photoprotection and lifelong dermatologic surveillance.

2. Alopecia

The first determination is scarring versus non-scarring , because scarring alopecia destroys follicles permanently and demands urgent treatment.

• Non-scarring Scarring (cicatricial)
• Follicular openings Preserved Lost — smooth shiny scalp
• Reversibility Potentially reversible Permanent

Examples Androgenetic, telogen effluvium, alopecia areata, tinea capitis, traction, trichotillomania Discoid lupus , lichen planopilaris, central centrifugal cicatricial alopecia, folliculitis decalvans

Loss of follicular ostia means scarring alopecia and warrants prompt dermatologic referral and biopsy.

Common non-scarring patterns

Androgenetic alopecia — patterned recession and vertex thinning in men, diffuse widening of the central part with preserved frontal hairline in women. Treated with topical minoxidil and, in men, finasteride.

Telogen effluvium — diffuse shedding beginning two to three months after a stressor : major illness, surgery, childbirth, severe weight loss, iron deficiency, thyroid disease, or a new drug. A positive hair pull test yields telogen (club) hairs. It recovers spontaneously once the trigger is corrected; the treatment is reassurance plus correcting iron deficiency or thyroid dysfunction.

Alopecia areata — sharply circumscribed round patches of complete hair loss with exclamation-point hairs at the margin. Autoimmune, associated with thyroid disease and vitiligo. May progress to alopecia totalis or universalis. Treated with intralesional corticosteroids and, in extensive disease, JAK inhibitors.

Tinea capitis — scaling with broken hairs and often occipital lymphadenopathy. Requires oral antifungal therapy ; topical agents do not penetrate the follicle.

Traction alopecia — from tight hairstyles; reversible early, scarring if prolonged .

In any woman with diffuse hair loss, check ferritin, thyroid-stimulating hormone and complete blood count , and consider androgen excess if there is hirsutism or menstrual irregularity.

3. Disorders of the Nails

A named blueprint subsection. Nails are a window into systemic disease, and the exam uses them as diagnostic clues.

Finding Description Associations

Clubbing Loss of the normal nail-fold angle, sponginess Lung cancer , bronchiectasis, cystic fibrosis, interstitial lung disease, cyanotic heart disease, inflammatory bowel disease, cirrhosis; not COPD alone

• Koilonychia Spoon-shaped concavity Iron deficiency
• Beau lines Transverse grooves A systemic insult that arrested growth; timing estimable from position

Onycholysis Distal separation from the bed Psoriasis , thyrotoxicosis, trauma, photo-onycholysis from tetracyclines

• Nail pitting Fine punctate depressions Psoriasis , alopecia areata
• Terry nails Proximal white with a distal pink band Cirrhosis , heart failure, diabetes
• Half-and-half (Lindsay) nails Proximal white, distal brown Chronic kidney disease
• Muehrcke lines Paired transverse white bands that do not move with growth Hypoalbuminemia
• Splinter hemorrhages Linear subungual streaks Trauma most often; endocarditis , vasculitis

Longitudinal melanonychia Pigmented band Benign in darker skin; worrying if single, widening, irregular, or with Hutchinson sign

Hutchinson sign — extension of pigment onto the proximal nail fold — suggests subungual melanoma and requires biopsy. A single new widening pigmented band in a lighter-skinned adult should not be dismissed.

Onychomycosis should be confirmed before treating , by potassium hydroxide preparation, culture or PAS staining, because psoriasis, lichen planus and trauma mimic it and systemic antifungals carry hepatotoxicity and drug interaction risk. Terbinafine is the usual oral agent.

Chronic paronychia is an inflammatory condition of wet-work exposure rather than a bacterial infection, and is treated with irritant avoidance and topical steroids; acute paronychia is bacterial and may require drainage.

4. Photosensitivity Dermatoses

A named blueprint subsection listing porphyria cutanea tarda and photodermatitis .

Drug-induced photosensitivity

• Phototoxic Photoallergic
• Mechanism Direct tissue injury Type IV hypersensitivity
• Onset Minutes to hours; first exposure Requires prior sensitization; 24 to 72 hours
• Appearance Exaggerated sunburn , sharply limited to exposed skin Eczematous , may spread beyond exposed skin
• Frequency Common Uncommon

Classic drugs Doxycycline , fluoroquinolones, amiodarone, thiazides, NSAIDs, voriconazole Sunscreen agents, fragrances, topical NSAIDs

Doxycycline photosensitivity is the archetype and should be mentioned whenever it is prescribed for acne or tick-borne illness in summer. Photo-onycholysis is a distinctive tetracycline effect.

Porphyria cutanea tarda

The most common porphyria and a purely cutaneous one.

Painless blistering and skin fragility on sun-exposed skin , especially the dorsal hands , with erosions, milia, scarring and hypertrichosis of the face

• No abdominal pain, no neuropathy — the contrast with acute intermittent porphyria
• Urine may fluoresce coral-pink under Wood lamp

A new diagnosis obliges an etiologic search: hepatitis C , HIV, alcohol, estrogen therapy, smoking, and iron overload including HFE mutations . Diagnosis is by elevated urinary uroporphyrins. Treatment is repeated phlebotomy or low-dose hydroxychloroquine with sun protection and removal of the precipitant; curing hepatitis C often resolves it.

Other photodermatoses

Polymorphous light eruption — the most common idiopathic photodermatosis. Pruritic papules and plaques appearing hours to days after the first substantial sun exposure of the season, with subsequent hardening as the summer progresses.

Solar urticaria — wheals within minutes of exposure.

Photoaggravated disease — subacute cutaneous lupus erythematosus presents with annular or papulosquamous lesions in a photodistribution, is strongly associated with anti-Ro (SSA) , and is a well-recognized drug-induced entity (hydrochlorothiazide, terbinafine, proton pump inhibitors, tumor necrosis factor inhibitors). Dermatomyositis produces a photodistributed violaceous eruption with the heliotrope rash and Gottron papules.