Inflammatory and Papulosquamous Disorders

1. Atopic Dermatitis Morphological types

   1. Papular eczema

   2. Follicular accentuation

   3. Dyschromia

   4. Lichenification

   5. Pityriasis alba

2. Psoriasis

   1. Morphology and color (violaceous and hyperpigmented with lichenification vs erythematous and devoid of silvery white scale)

3. Contact Dermatitis

   1. Morpholology and color (hyperpigmentation vs erythema vs LPP-like in South Asian population)

4. Pityriasis Lichenoides Chronica

   1. Morphology and color (hypopigmented patches or vitilgo like in darker skin vs erythematous guttate papular appearance in light skin)

5. Pityriasis Rosea

   1. Morphology and color (similar distribution hyperpigmented to violeceous vs. erythematous; papular variant)

6. Seborrheic Dermatitis

a Facial Morphology and color (petaloid seborrheic dermatitis and hypopigmentation vs erythema)

b. Scalp - Morphology and color (more scale vs sebopsoriasis like in lighter skin)

1. Lichen Planus

   1. Morphology and color (similar morphology except hypertrophic LP darker violet or brown to black vs bright violet in lighter skin)

2. Lichen nitidus (B)

   1. Color (Highlight differences in flesh color)

       

Infections

1. Tinea Versicolor

   1. Morphology and color (less pink or red or hypopigmented or hyperpigmented; sequelae of pigmentation remains)

2. Tinea Capitis

   1. Morphology (kerion)

3. Tinea Corporis

   1. Color (erythema vs Hyper- or hypopigmentation)

4. Impetigo

   1. Morphology and color (erythema vs hyperpigmentation; both have honey colored crust)

5. Cellulitis

   1. Color (lack of erythema)

6. Syphilis

   1. Morphology (secondary syphilis with moth eaten alopecia; palmar lesions, facial rash)

7. Verruca plana

   1. Color (skin colored papules that can be missed)

8. Molluscum

   1. Color (skin colored papules that can be missed)

       

      9a. COVID-19

Infestations/Bites

1. Scabies

   1. Morphology and color (differences in location such as inter-digital; more erythematous)

2. Pediculosis

3. Erythema Migrans

   1. Color (lack of erythema vs hyperpigmentation and the intensity of violet hues)

       

Drug Reactions

1. DRESS

   1. Color (pigmentary differences)

2. Morbilliform Drug

   1. Color (pigmentation difference both popular)

3. Fixed Drug

   1. Color (lack of erythema vs hyperpigmented to black hue)

4. Steven’s Johnson Syndrome/Toxic Epidermal Necrolysis

   1. Morphology and color

Follicular Disorders

1. Acne

   1. Morphology and color (post-inflammatory hyperpigmentation and sequalae; definition of scarring)

2. Rosacea

   1. Morphology and color (under-diagnosed in darker skin)

3. Perioral dermatitis

   1. Morphology and color (pigmentation difference vs erythema

4. Folliculitis

   1. Morphology and color (similar to acne)

5. Hidradenitis Suppurativa

   1. Morphology and color (pigmentation difference vs erythema (keloidal scarring)

6. Pseudofolliculitis Barbae

   1. Morphology and color (pigmentation difference vs erythema)

Benign Neoplasms

1. Seborrheic Keratosis and Dermatosis Papulosis Nigra

   1. Morphology and color (pink vs brown; size and distribution)

2. Dermatofibroma

   1. Color (pink vs brown)

3. Scars

   1. Morphology (hypertrophic scar vs keloid

Malignancies

1. Basal Cell

   1. Color (pigmented vs classical pink)

2. Squamous Cell

   1. Color (pigmented vs classical pink)

3. Melanoma

   1. Morphology and color (location acral and melanonychia)

4. CTCL

   1. Morphology and color (hypopigmented Mycosis fungoides; follicular or sryingotrophic which may look like keratosis pilaris)

Alopecias

1. Lichen Plano Pilaris and Frontal Fibrosing Alopecia

   1. Morphology (triad of follicular papules, LPP and FFA in darker women)

2. Traction Alopecia

   1. vs FFA

3. Discoid Lupus Erythematosis

   1. Morphology and color (degree of hypopigmentation; follicular plugging)

4. Folliculitis Decalvans

   1. Morphology and color (differences and keloid scarring

5. Dissecting Cellulitis (B)

   1. Color differences

       

Pigmentary Disorders

1. Melasma

   1. Color (degree of pigmentation; telangectasias; confluence of pigmentation; extra-facial melasma)

2. Postinflammatory Pigmentation

   1. vs PIE

Photosensitivity

1. PMLE(B)

2. Chronicactinic dermatitis

   1. Morphology and color (more erythematous in white skin and darker and more lichenified in darker skin

Vascular Disorders

1. Purpura and vasculitis

   1. Morphology and color (violeceous)

Miscellaneous

1. Extrinsic Aging

   1. Morphology and color (rhytids and lentigines vs no lentigines and fine rhytids)

2. Sarcoidosis

1. Diabetes Mellitus

   1. Acanthosis Nigricans (color difference)

   2. Diabetic Dermopathy (color difference)

       

Idiopathic Guttate Hypomelanosis

1. 1. Morphology and color (quantity and size in darker skin hues)

2. Urticarial Bullous Pemphigoid

   1. Morphology and color