Integumentary System

Abnormal Microscopic Findings

Finding Description Diseases
Hyperkeratosis ↑ Stratum corneum Psoriasis
Parakeratosis Nucleus in stratum corneum Psoriasis
Hypergranulosis ↑ Stratum granulosum Lichen planus
Acanthosis ↑ Stratum spinosum Acanthosis nigricans
Acantholysis Cleft in stratum spinosum Pemphigus vulgaris
Spongiosis Fluid in epidermis Eczema
Exocytosis Leukocyte in epidermis -

Rashes Associated with Infection

Rash Pathogens Location
Condyloma accumulata HPV Genital
Condyloma lata Treponema pallidum Genital
Ecthyma gangrenosum Pseudomonas aeruginosa Anywhere
Erythema infectiosum [Fifth disease] Parvovirus B19 Face → Trunk & Extremities
Erythema marginatum Group A streptococcus (GAS) Trunk
Erythema migrans Borrelia burgdorferi Anywhere
Erythema multiforme Mycoplasma & HSV Anywhere
Erythema nodosum Tuberculosis
Leprosy
Histoplasmosis		 Anywhere
Hand-foot-mouth disease Coxsackie A virus Extremities → Trunk
Herpes simplex HSV1 & HSV2 Mouth & Genital
Herpes zoster [Shingles] VZV Dermatome
Measles Measles virus Head → Toe
Molluscum contagiosum Poxvirus Anywhere
Pityriasis rosea Roseolovirus Trunk
Rocky Mountain spotted fever Rickettsia rickettsii Extremities → Trunk
Roseola infantum Roseolovirus Trunk → Face & Extremities
Rubella Rubella virus Head → Toe
Seborrheic dermatitis Malassezia Anywhere
Tinea [Dermatophytosis] Dermatophytes Anywhere
Tinea versicolor Malassezia Trunk
Varicella [Chickenpox] VZV Face & Trunk → Extremities
Verruca vulgaris HPV Face & Extremities

Rashes Associated with Non-Infectious Diseases

Rash Associations Location
Acanthosis nigricans Insulin resistance
Visceral malignancy		 Axilla & Neck
Atopic dermatitis - Joints
Erythema multiforme Stevens-Johnson syndrome (SJS)
Toxic epidermal necrolysis (TEN)		 Anywhere
Erythema nodosum Drugs
Inflammatory bowel disease (IBD)
Sarcoidosis
Non-Hodgkins lymphoma		 Anywhere
Erythema toxicum Neonates Face & Trunk & Extremities
Migratory thrombophlebitis
Trousseau syndrome		 Pancreatic adenocarcinoma Veins
Necrolytic migratory erythema Glucagonoma Face & Extremities
Pyoderma gangrenosum Inflammatory bowel disease (IBD) Anywhere
Seborrheic dermatitis Parkinson disease
HIV infection		 Anywhere
Seborrheic keratosis
Leser-Trélat sign		 Visceral malignancy Trunk

Benign Skin Rashes in Newborns

  • Cradle cap
  • Diaper rash
  • Erythema toxicum
  • Milia
  • Mongolian spots
  • Nevus simplex
  • Strawberry hemanangioma

Degrees of Skin Burns

Degree Thickness Depth Blanchable Painful Blistered Color
1 Superficial Epidermis + + - Erythema
2 Superficial partial Papillary dermis + + + Erythema
  Deep partial Reticular dermis ± ± ± Erythema
White
3 Full Subcutis - - - White
Eschar

Types of Skin Grafts

Types of Flaps

Blood Supply

  • Random
  • Axial
    • Pedicled
    • Free

Proximity

  • Local
    • Advancement
    • Rotation
    • Transposition
  • Regional
  • Distant

Composition

  • Cutaneous
  • Fasciocutaneous
  • Musculocutaneous
  • Osteocutaneous

Stages of Ulcers

Stage Thickness Depth
1 Superficial Epidermis
2 Partial Dermis
3 Full Subcutis
4 Full Muscle & Bones

Wagner Classification for Ulcers

Stage Description
1 Skin
2 Deep w/o abscess
3 Osteomyelitits
4 Localized gangrene
5 Extensive gangrene

Wallace Rule of Nines

Etiology of Erythema Nodosum {DOSUM}

  • Drugs
    • Sulfa drugs
    • NSAIDs
    • Iodides
  • Oral contraceptive pills (OCPs)
  • Inflammatory bowel disease (IBD)
  • Sarcoidosis
  • Non-Hodgkins lymphoma
  • Microbiology
    • Tuberculosis
    • Leprosy
    • Histoplasmosis

Presentation of Lichen Planus {6P}

  • Planar
  • Purple
  • Polygonal
  • Pruritus
  • Papules
  • Plaques

Treatment of Atopic Dermatitis

  • Moisturizers
  • Topical corticosteroids
  • Topical tacrolimus
  • Phototherapy

Treatment of Urticaria

  • Oral H1 antagonists
  • Oral corticosteroids

Treatment of Contact Dermatitis

  • Allergen avoidance
  • Moisturizers
  • Topical corticosteroids
  • Topical tacrolimus
  • Oral corticosteroids

Empirical Antibiotics for Cellulitis

  • Anti-streptococcal penicillin

Empirical Antibiotics for Skin Abscess

  • Anti-MRSA

Empirical Antibiotics for Necrotizing Fasciitis

  • Anti-MRSA
  • β-lactams & β-lactamase inhibitors
    Carbapenems

Treatment of Acne Vulgaris

  • Topical benzoyl peroxide
  • Topical tretinoin
  • Topical antibiotics
  • Oral antibiotics
  • Oral isotretinoin

Treatment of Seborrheic Dermatitis

  • Topical tar
  • Topical zinc pyrithione
  • Topical selenium disulfide
  • Topical antifungals
  • Topical corticosteroids
  • Oral antifungals
  • Oral corticosteroids

Treatment of Verruca Vulgaris [Wart]

  • Topical salicylic acid
  • Topical trichloroacetic acid
  • Topical podophyllin
  • Topical 5-fluorouracil
  • Topical imiquimod
  • Cryotherapy
  • Surgical excision

Treatment of Precancerous Skin Lesions

  • Topical tretinoin
  • Topical 5-fluorouracil
  • Topical imiquimod
  • Photodynamic therapy
  • Cryotherapy

Types of Melanocytic Nevi

Features of Melanoma {ABCDE}

  • Asymmetry
  • Border irregularity
  • Color variation
  • Diameter > 6 mm
  • Evolution

Types of Melanoma

  • Superficial spreading melanoma
  • Nodular melanoma
  • Lentigo maligna melanoma
  • Acral lentiginous melanoma

Management of Skin Cancer

Cancer Management
Squamous cell carcinoma Cryotherapy
Electrodesiccation
Surgical excision
Mohs micrographic surgery
Basal cell carcinoma Cryotherapy
Electrodesiccation
Surgical excision
Mohs micrographic surgery
Melanoma Surgical excision

Breast Imaging Reporting and Data System (BI-RADS)

Category Interpretation Management Likelihood of cancer
0 Inconclusive Repeat -
1 Negative Routine 0
2 Benign Routine 0
3 Probably benign Every 6 months < 2%
4 Suspicious Biopsy 2 ~ 95%
5 Highly suggestive Biopsy > 95%
6 Biopsy-proven - -

Breast Tumors

Epithelial Tumors

  • Fibrocystic change
  • Intraductal papilloma
  • Ductal carcinoma in situ (DCIS)
    Invasive ductal carcinoma (IDC)
  • Lobular carcinoma in situ (LCIS)
    Invasive lobular carcinoma (ILC)
  • Medullary carcinoma

Stromal Tumors

  • Fibroadenoma
  • Phyllodes tumor

Molecular Subtypes of Breast Cancer

Subtype Receptors Mutations
Luminal A PR & ER -
Luminal B PR & ER -
HER2-enriched HER2 -
Basal-like - BRCA
Claudin-low - BRCA
Interferon-rich - BRCA

Types of Flaps for Breast Reconstruction

  • Transverse rectus abdominis myocutaneous (TRAM) flap
  • Latissimus dorsi (LD) flap
  • Deep inferior epigastric perforator (DIEP) flap
  • Superficial inferior epigastric artery (SIEA) flap
  • Gluteal flap
  • Transverse upper gracilis (TUG) flap
  • Profunda artery perforator (PAP) flap