Dermatology Flashcards
What is “Skin of Color”
Pigmented Skin
What are the racial/ethnic groups that are considered to have “Skin of Color”?
People of African Diaspora
American Indians/Alaskan Natives
Asians and Pacific Islanders
Hispanics and Latinos
Why study skin of color?
1) the mid 21st century, people with skin of color will constitute the majority of the population of the U.S. (No racial or ethnic majority group)
2) increased recognition of health disparities in cutaneous diseases in patients from different racial/ethnic groups
3) Improve understanding of the fundamental differences in the structure and function of skin of color
4) Create novel and/or improved therapies that take skin pigmentation and cultural preferences into account
5) Include this topic in dermatology educational curricula
Studying skin of color allows us to see differences in what?
- Phenotypic expression
- Clinical course/response to treatment
- Outcomes
Why do differences in Phenotypic expression, Clinical course/response to treatment,
Outcomes exist?
- Biological factors
- Socioeconomic factors
- Behavioral factors
- Likely a combination of factors
What is all the same in all races?
The structure and function of skin
What are differences in skin between races?
- Pigmentation
- Hair structure
- Skin aging
- Fibrosis
- Differences in predisposition to specific dermatologic diseases
- Differences in clinical presentation
- The contribution of environment and cultural practices
What is the one feature that is unique to skin of color?
PIGMENTATION
T/F
The number of melanocytes is different in different races / skin pigmentation
False
The number of melanocytes is generally constant regardless of race / skin pigmentation
Racial differences in constitutive skin color are due to?
The amount and distribution of melanin in the skin
What regulates the amount and distribution of melanin in the skin?
Melanosome Number, size, composition, and distribution/aggregation
What does melanin do?
absorbs UV radiation and provides photoprotection
What is the natural SPF for dark skin individuals?
SPF 13
accomplished by melanin
What are the two types of melanin?
Eumelanin
Pheomelanin
What is Eumelanin?
brown/black pigmentation
Where is Eumelanin found?
- Found in all skin types but more abundant in people with dark skin
- Found in grey, black, blonde, and brown hair (except red hair)
What is Pheomelanin?
Red/yellow pigmentation
Where is Pheomelanin found?
- Found in light and dark skin but most abundant in people with red hair
- Particularly concentrated in the lips, nipples, glans penis, and vagina
- Women > men
What is particularly different about Pheomelanin that is not a concern of eumelanin?
Pheomelanin produces oxygen radicals (carcinogenic) when exposed to UV radiation
What is an epidermal melanin unit?
The association of a melanocyte with approximately 30-40 surrounding keratinocytes to which it transfers melanosomes.
Where does all the action happen between the melanocytes and the keratinocytes.
Basal Layer
What are melanosomes?
Organelle within which melanin pigments are synthesized
- Matrix proteins (scaffolding)
- Biosynthetic enzymes (Tyrosinase)
What are the 4 stages to melanosome development?
- Spherical, no melanin deposition
- Oval, obvious metric in the form of parallel longitudinal filaments; minimal deposition of melanin; high tyrosinase activity
- Oval; moderate deposition of melanin; high tyrosinase activity
- Oval; heavy deposition of melanin; electro-opaque; Oval; minimum tyrosinase activity
How do Melanosomes migrate?
Migrate via microtubules into the dendrites in preparation of transfer into the neighboring keratinocytes
How are melanosomes distributed in darker skin individuals?
single melanosomes in lysosomes of keratinocytes, higher volume. Take longer to degrade (enzyme that degrades melanosomes act slower.
How are melanosomes distributed in darker skin individuals?
cluster of 2-10 melanosomes in lysosomes of keratinocytes and they tend to degrade quickly
What is the stage, size, and number of melanosomes in lightly pigmented skin
- Stage II, III
- 0.3-0.5 micrometer
- <20/cell
What is the stage, size, and number of melanosomes in darkly pigmented skin
- Stage IV
- 0.5-0.8 micrometer
- > 200/cell
Compare White, Asian, and Black skin melanin concentration before and 7 days after radiation exposure.
White
Before: very, very little melanin (2.79)
After: increase but still a little melanin (3.46)
(kind of remains in a single/lower layer)
Asian
Before: Some Melanin (4.5)
After: Small increase in melanin (4.78)
Black
Before: A lot of melanin (20.52)
After: Even more (26.18)
(have more spread into other layers)
Up to 5x as much ______ reaches the upper dermis of white skin compared to black skin.
UV
What is UV-induced apoptosis?
A mechanism in which potentially precancerous cells are removed. This occurs significantly more in Black skin.
Darker Skin has larger, more numerous, singly-distributed melanosomes that are what?
That contain more melanin, are distributed throughout epidermis (including upper layers), and degrade more slowly.
Darker skin is more efficient at what?
UV Filtering
- More effective at preventing UV-induced DNA damage in the lower epidermis (including keratinocyte stem cells and melanocytes)
- Decreases vitamin D production in the skin
Why does darker skin have a decreased risk in cancer?
UV damaged cells are removed more efficiently in darker skin
What is the Fitzpatrick skin type chart?
Originally 4 skin types and 2 more were added. It was used to determine race in the past but in reality can not tell you race or ethnicity.
Fitzpatrick skin type I
White
Always burns
nerver tan
Fitzpatrick skin type II
Beige
Usually Burns
tans with difficulty
Fitzpatrick skin type III
Light brown
Sometimes burns
slow tanning
Fitzpatrick skin type IV
Medium brown
rarely burns
fast tanning
Fitzpatrick skin typeV
dark brown
rarely burns
fast and easy tanning
Fitzpatrick skin type VI
black
almost never burns
fast and dark tanning
What is post inflammatory hyper pigmentation?
melanocytes dies and release melanosome and deposit into dermis
- Molecular pathogenesis still unclear
- Common after even minor inflammatory insults in skin of color
- Can be long-lasting and may be more troubling to patients than the original dermatosis
Slide 21
Slide 21
What is Photodermatosis?
rashes caused by sun exposure
- Different subtypes and clinical presentation in skin of color
- Related to reactive oxygen species generated from UV irradiation of large amounts of melanin
What is the Most common photodermatosis amongst individuals with skin of color and caucasian skin?
Polymorphous Light Eruption (PMLE)
In Skin of Color: Papular (pin-point) and Iichenoid variants are more common
What is the second most common photodermatosis in skin of color?
Chronic Actinic Dermatitis (Chronic, recalcitrant) - Prurigo-like and Lichenoid variants are common
Whites have better prognosis
Actinic Prutigo is more common in who?
- Latin American mestizos
- North American
- Indians/Alaskan natives
- Ethnic Chinese
- HLA-A24 and HLA-CW4
(uncommon in caucasians)
Solar Urticaria is more common in who?
Caucasians (uncommon in skin of color)
Actinic Lichen Planus is more common in who?
Middle East, and India
uncommon in West Africa, rare in caucasians
HIV Photosensitivity is more common in who?
Lichenoid; erythroderma
What is the difference between skin of color and caucasian when it comes to drug-induced photosensitivity?
Skin of color- Photoallergic rxn more common
Caucasian - Phototoxic rxn more common
What is Pigmentary Disorders?
Bod deposits extra pigment
Erythema dyschromicum perstans, lichen planus pigmentosus, melasma
Melasma
More common on cheeks and temples. Also more common in women. Related to hormone and sun exposure.
Erythema dyschromicum perstans (Ashy Dermatosis) mainly occurs in which population?
South and central America.
These to conditions are related but occur in different populations
Ashy dermatosis and Lichen Planus Pigmentosus
Lichen Planus Pigmentosus mainly occurs in which population?
African decent or south east Asia decent
How does pigment affect cutaneous diseases?
Pigment often changes the phenotypic appearance of cutaneous diseases
How is psoriasis presented in caucasians versus skin of color?
Caucasians - Pink plaques w/ silver scales
In skin of color you do not see the red, just the silver
How is Lichen Planus presented in caucasians versus skin of color?
Caucasians - small, pink/purple itchy spots (classic location on wrist)
Skin of color- spots are darker and just appear different
How is Atopic dermatitis (Eczema) presented in caucasians versus skin of color?
Acute flare is red and itchy in caucasian. If the person is no longer red or itchy it is considered chronic but in skin of color it does not appear red. So skin of color patients are misdiagnosed and assumed to be in the chronic stage due to lack of redness. Ask the patient if they are itchy, if yes then it is an acute flare
What are the Cutaneous Diseases with increased prevalence or worse prognosis in patients with pigmented skin?
- Acne keloidalis nuchae (common in black men)
- Central Centrifugal Cicatricial Alopecia (more common in black women)
- Cutaneous and systemic lupus
- Cutaneous T-cell lymphoma
- Hidradenitis suppurativa
- Keloids
- Some photo-exacerbated disorders
- Vitiligo (more impactful in skin of color)
- Pseudofolliculitis barbae
- Sarcoidosis
- Scleroderma
- Traction alopecia
Fundamental difference in skin pigmentation contributes to what?
- Lower susceptibility to deleterious effects of UV radiation
- Increased susceptibility to vitamin D deficiency
- Increased susceptibility to disorders of pigmentation
- Race/ethnicity identity and value
