Pigmentation Disorders Flashcards
What determnes skin colour?
The number of melanocytes is equal in all skin types
- In darker skin melanosomes are larger, more numerous and they contain more melanin
What are the Fitzpatrick skin types?
I - burns, does not tan
II - burns, tans a little
III - burns slightly, tans evenly
IV - burns sometimes
V - burns rarely, brown skin
VI - never burns, dark brown skin
What is lichen planus?
a chronic inflammatory disease characterized by skin and/or mucosal lesions
- the skin lesions are characterized by the 6Ps (planar, polygonal, pruiritic, purple papules and plaques
- involvement of the oral mucosa manifests as reticular white lines (Wickam striae)
What is lichen simplex?
a benign skin condition characterized by lichenified plaques with excoriations and moderate to intense pruritis that leads to persistent rubbing and/or scratching to provide symptom relief
- result from habitual behaviour or is a manifestation of chronic ecxematous inflammation
e.g. scratching in resonse to stress
What is post inflammatory hyperpigmentation?
an acquired hyperpigmentation disorder that results from injury (skin abrasion), inflammation (atopic dermatitis) or procedures (crypotherpay, radiation)
- manifests as pigmented macules or patches with irregular borders and can persist if the underlying cause is not treated
- typically this affects individuals with dark skin
Treatment for post-inflammatory hyperpigmentation?
Topical treatment
1. retinoids: tretinoin, tazarotene, adapalene
2. hydroquinone
Procedures
3. glycolic, salycilic acid, lactic acid
4. sunscreen
Best sunscreen to use in PIH?
- Sun Protection Factor 50
- Tinted sunscreens containing iron oxides protect against Visible Light as well as UVLight
- Tinted sunscreens containing pigments such as ferrous oxide
combined with zinkoxide or titanium dioxide
What can be used to bleach the skin?
corticosteroids
e.g. hydroquinone
Why do people bleach?
- smooth and healthy skin
- beauty enhancement
- social factors (job, marriage prospects)
Hydroquinone side effects?
- Vitiligo-like depigmentation
- Allergic contact eczema with postinflammatory hyperpigmentation
- Exogenic ochronosis
How bleaching creams work?
Corticosteroids inhibit melanocyte proliferation, melanocyte secretory function and inflammation
- They should only be used for medical combination treatment of PIH,
e.g. with retinoids, for a short period of time
Side effects of topical corticosteroids?
- Atrophy of dermis and epidermis
- Masking of infections
- Peri-oral and peri-orbital dermatitis, steroid acne
- Striae, esp in arm pits and groins
- Teleangiectasia
Name hypopigmented disorders?
- Vitiligo variants
- Congenital
- Infections
- Other acquired
What is vitiligo?
- Chronic acquired auto-immune skin disease
- Acquired, chalk-white, welldefined depigmented macules
Prediliction sites for vitiligo?
- periorbital, fingers, lips, nose, perineum, axillae
- points of pressure: elbow, knees, lumbosacral
Does a vitiligo patient have melanocytes?
no
Psychosocial burden of vitiligo?
Can result in severe difficulties in social adjustment, stigma
Epidemiology of vitiligo?
- Prevalence 0.1 – 2 %
- Male : female 1:1
- Onset: any age, 50% 10-40 years
- Mostly < 25% of BSA involved
- More progressive - if onset at young age
Genetics in vitiligo?
30-45% positive family history
Pathogenesis of vitiligo?
Autoimmune theory
* Selected melanocytes destroyed by autoimmune reaction (apoptosis)
Treatment for vitiligo?
- Topical
* Steroids / calcineurin inhibitors
* Vit D Analogs
* Combinations
* Sunscreens/ Covering
* Janus-Kinase (JAK)-inhibitors - Camouflage
- Phototherapy
- Surgery only for small stable areas
or segmental vitiligo, eg minigrafts,
single hair grafts
Surgical methods in treating vitiligo?
possibly helpful for small areas, segmental vitiligo
1. Minigrafts
2. Single hair graft,
3. Split skin graft,
4. Future: Cultured melanocytes?
Reducing psychosocial burden of vitiligo?
- patient support groups
- role models
- psychological support
What is epidermal naevus?
- Present at birth or occur in infancy
- Hyperplasia of epidermal structures
- Closely set verrucous papules, circumscribed, often linear, may appear in Blaschko´s Lines on the trunk
What is achromic naevus?
- Cutaneous mosaicism
- altered clone of melanocytes with a decreased ability to make melanin
What is xeroderma pigmentosum?
- Rare genodermatosis, autosomal recessive inheritance
- Inability of a cell to repair DNA damage caused by UV
➢ photosensitivity
➢ premature skin aging
➢ skin, ocular, neurological & oral lesions
➢ cutaneous & internal malignancies at early age - No cure, early mortality
What is leprosy?
a chronic infection caused by Mycobacterium leprae that typically manifests with hypopigmented skin lesions, nerve thickening, and peripheral nerve palsies
What is onchoceriasis?
aka river blindness
- caused by onchocerca volvulus
- ocular involvement may cause blindness
- onchocercomata (subcutneous nodules): deep, nonpalpable nodules containing adult worms that are found over various bony prominences
- generalized pruritic lesions
- skin atrophy causing a cigarette paper appearance
What is pityriasis versicolor?
- Round hypopigmented sharply defined, scaling macules
- affecting trunk and chest, neck and shoulder area, abdomen, upper arms and thighs
- hypomelanosis can remain long after treatment
What is used to test for pityriasis versicolor?
Stretch test
- gentle abrasion of the surface accentuates the scaling
Ddx for acquired hypopigmentation?
Inflammatory or post-inflammatory
1. Guttate hypomelanosis
2. Pityriasis alba
3. Scars
4. CDLE
5. Bullous diseases
6. Psoriasis, Seborrhoic dermatitis
7. Lichen sclerosus
8. Chemical
9. Burns, Cryotherapy, Dermabrasion
What is alopecia areata?
- History of / or ongoing hair loss
- No loss of pigment from scalp, only white hair
What is idiopathic guttate hypomelanosis?
- Common, shins
- Complete pigment loss
- Sun damaged skin
- Other trauma
What is pityriasis alba?
dry, scaly, hypopigmented skin lesions that are self limiting and harmless
- commonly seen in children
What is hirsutism?
What is chronic discoid lupus erythematodes?
- onset 20-45 years,
- Females > males,
- Chronic, indolent
- Well demarcated, scaly, indurated, red, later atrophic, scarring, hypopigmented discoid plaques
What is bullous pemphigoid?
an autoimmune blistering skin disorder caused by circulating antibodies against BP antigen on hemidesmosomes
- tense subepidermal blisters develop and can become hemorrhagic or turbid
- recurrent lesions typically occur in skin flexures (groin, axilla) and over the abdomen, mucous membranes are usually spared
What is anogenital lichen sclerosus?
chronic inflammatory dermatosis that is characterized by pruritic, white plaques with epidermal atrophy and scarring
- ass. with increased risk of squamous cell carcinoma and most commonly affects postmenopausal women
