Download hypo and hyperpigmentation

Disorders
of
Pigmentation
By
Dr.Alaa A. Naif
Feb 15, 2015
Causes of hypopigmentation
Infection: onchoceciasis, post-kala azar dermal
leishmaniasis, , leprosy and pityriasis versicolor
Postinflammmatory hypopigmentation: psoroiasis
Pityriasis alba: mild type of atopic dermatitis
Genetic diseases: piebaldism, albinism
Chemical : rubber
Pharmacological: topical and intralesional steroids
Idiopathic: vitiligo
Vitiligo
It affect 0.5-2% of general population worldwide
Average age of onset is 20 years but any age can
be inflicted by this disease
Characterized by absence or decrease of
functional melanocytes reflected by absence or
decreased DOPA-positive melanocytes
Pathogenesis
Multifactorial: Genetic + Environmental
Genetic:
Susceptibility genes are AIS especially in vitiligo
associated with autoimmune diseases
Environmental:
Autoimmune theory:
Humoral immunity: association with other autoimmune diseases in particular hypo and hyper
thyroidism in addition to Addison’s , DM etc…
Cellular immunity: T cells that infiltrate
perilesional epidermis are predominantly CD8 T
cells
Intrinsic defects of melanocytes theory:
dilatation in rough endoplasmic reticulum
Defective free radical defense: H2O2
overproduction in lesional skin leads to
oxidative damage of melanocytes
Neural theory:especially in segmental vitiligo. They
believe that neuropeptides released from nerve
endings cause decreased melanin productio
Viral theory:Cytomegalovirus DNA has been
identified in skin biopsy specimen of some
patients with vitiligo, causing damage to
melanocytes
Convergence theory: available data suggest that
vitiligo is multifactorial and may be the end result
of several different pathologic pathways
Clinical Presentation
Present as asymptomatic, non-scaly
depigmented macules and patches
Affect face (periorificial), hands, knees, elbows,
ankle, nipple, anogenial and and sacrum
Can present as isolated localized patch of grey
or white hair (poliosis) or as premature diffuse
graying of hair ( canities)
Classification
Localized
Focal
Unilateral(segmental): stop abruptly at the
medline
Generalized
Acrofacial: extremities and face
Universal: complete or nearly complete
Treatment
1)When less than 20% of BSA is affected by
vitiligo
Topical corticosteroids: first option
Topical immunosuppressant e.g. tacrolimus
Topical pseudocatalase
Surgery: graft or cultured melanocytes for vitiigo
unresponsive to topical Rx
2)When more than 20% of BSA is affected by
vitiligo
Narrowband UVB(311 nm): first choice
Psoralen plus phototherapy(PUVA): psoralen
can e applied topically(topical PUVA) or oral
(oral PUVA) followed by exposure to artificial
UV light or natural sunlight.
Permanent depigmentation: e.g. monobenzyl
ether of hydroquinone is used when vitiligo
involve more than 50% of BSA and
unresponsive to phototherapy
Others: systemic anti-oxidant and excimer laser
Oculocutaneous albinism
Autosomal recessive group of diseases
characterized by diffuse pigmentary dilution due to
partial or total absence of mealnin in skin, hair
follicles and eyes despite the normal number of
melanocytes in skin
Eyes may be affected by decreased visual acuity,
nystagmus and photophobia
Those patient are at increased risk for skin cancer
Treatment is photoprotection, photoprotection and
photoprotection
OCA1A
OCA1B
OCA2(BROWN)
Type of
albinism
Gene defect
OCA1A
Tyrosinase(complete White skin, white hair and blue eyes (some
absence of activity) are blind)
OCA1B
Tyrosinase (Partial
absence of activity)
OCA2
Clinical features
Develop some pigmentation of hair and skin
with age (yellow OCA)
Skin and hair are light brown (brown OCA)
SCC in albinism patient
Piebaldism
Autosomal dominant, cc by stable depigmented
patches on anterior trunk, mid extremities,
central forehead and frontal scalp(white
forelock), sparing the back
Present at birth
The involved skin has no melanocytes
Treatment: topical steroid and phototherapy is
not effective. Auto graft from normal skin is
successful
Idiopathic guttate hypomelanosis
It is a very common disorder
Well-defined asymptomatic porcelain-white macules
that don’t change in size and don’t repigment
Mostly involves forearms and legs (photoexposed
areas)
Affect dark skinned people more than caucasian
Incidence increase with age and female are affected
more than male
Etilology is unknown but sun exposure may play a
role
Treatment: cryotherapy and sun protection.
Causes of hyperpigmentation
Infection: Pityriasis versicolor
Friction: macular amyloidosis
Drug-induced : amiodarone, silver, gold, iron,
hydoquinone, minocycline
Postinflammatory hyperpigmentation: lichen
planus and fixed drug eruption
Physical:erythema ab igne which is due to longterm exposure to heat e.g. laptop on the thighs
Idiopathic: melasma
Melasma
Synonyms: chloasma, mask of pregnancy
It is most prevalent among young to middle aged
women
Hispanic, Asian, African or middle eastern
descent are inflicted by this disease
Pathogenesis
Exposure to UV : fading of lesion in winter,
involvement of sun-exposed areas and sparing
of philtrum
Genetic/ethnic predisposition : Mostly it is
related to darker skin type
Hormones: OCP, pregnancy (appearnace or
exacerbation)
Autoimmune thyroid diseases
Clinical features
Brown or gray patches on the face, but may affect
extensor forearm and central upper chest
May lighten or disappear after delivery in light
skinned women but may persist in dark skinned
Using Wood’s lamp, melasma is subdivided into
epidermal( the lesion is accentuated), dermal (the
lesion blend with the surrounding) and mixed
Treatment
Sun protection , sun protection and sun protection
Hydroquinone( tyrosinase inhibitor). Side effects:
allergic and irritant contact dermatitis, ochronosis
Topical retinoids( inhibitor of tyrosinase
transcription)
Other tyrosinase inhibitors e.g. kojic acid
Chemical peels: using salicylic acid and glycolic acid
Laser: Q-switched laser and fractional laser
Dermabrasion
Ochronosis
There are two types:
Exogeneous: due to long-term application of
hydroquinone, and products containing mercury,
resorcinol and phenol
Rx: cessation of offending drug
Endogeneous: due to defect in homogentisic acid
oxidase. CC by deposition of pigment in cartilage of
ear, nose and on sclera(osler sign) and by arithritis
Rx:low protein, low tyrosine and low pheylalanine
diet
Macular amyloidosis
Pruritic confluent or rippled hyperpigmented
macules and patches
Mostly involve upper back and forearms
Women affected more than men
local friction from nylon brushes, towels and
other rough materials contributes to the
production of this disease
Treatment: breaking itch-scratch cycle ,
stopping friction and use of topical steroids
plus keratolytics
Drug Reactions
Epidemiology
The skin is one of the most common targets for
adverse drug reactions
women are more susceptible than men
Paradoxically, the incidence of most
immunologically mediated drug eruptions is
increased in the setting of immunosuppression;
for example, in patients with AIDS
The incidence of adverse reactions also increases
with the age of the patient
Pathogenesis
The mechanism
Example
1. Immunological mechanisms
(unpredictable)
IgE-mediated e.g. urticaria
2. Non-immunological mechanisms
(predictable)
Phamacological side effects e.g.
Chemothearapy cause hair loss that
cannot be seperated from the desirable
action of this drug
3. Idiosyncratic (unpredictable and can
not be explained on the basis of
pharmacological properties of drug)
Stevens- Johnson syndrome/Toxic
epidermal necrolysis
APPROACH TO DETERMINE THE
CAUSE OF A DRUG ERUPTION
1. Clinical characteristics:
Type of the lesion e.g. maculopapular lesions in
morbilliform drug eruption ,
Distribution of lesions e.g. recurrence of the lesion
at exactly the same site with each exposure to the
same drug in fixed drug eruption ,
Mucous membrane involvement e.g. in SJS/TEN
Associated features such as fever,
lymphadenopathy and visceral involement e.g. all
are manifested in DRESS
2. Chronological factors:
Document all drugs to which the patient has been
exposed and the dates of administration
Date of eruption
Time interval between drug introduction and skin
eruption because most of drug eruption occurs
within 1-3 weeks after initiation of new drug
Response to removal of the suspected agent
Response to rechallenge(re-administration of drug)
such as in fixed drug eruption which is not lifethreatenening
3. Literature search e.g medline
Note: Diagnostic or confirmatory test to identify
the responsible drug is not available yet
Type of drug reaction
Exanthematous eruption
(the most common drug
reaction)
Clinical manifestation
Macules and papules in symmetrical
distribution
Urticaria, angioedema and
anaphylaxis
Causative drugs
Sulfonamides
Penicillin
Cephalosporins
Penicillins
Cephalosporins
NSAIDs
Contrast media
Fixed drug eruption
Well-defined erythematous plaque with a
dusky hue occur at the same site with every
subsequent exposure to the same drug
TMP-SMX
NSAIDs
Tetracyclines
Pseudoephedrine
DRESS(drug reaction with
eosinophilia and systemic
symptoms) or
hypersensitivity syndrome
Maculopapular eruption, facial edema.
Lymphadenopathy, visceral involvement and
peripheral eosinophilia
Anticonvulsants
Sulfonamides
Allopurinol
SJS/TEN( Stevens-Johnson
syndrome/ Toxic epidermal
necrolysis)
Maculopaular eruption, severe mucous
membrane invlovement e.g. mouth, eyes,
genitalia and positive Nikolsky sign
(sloughing of skin on pressure by finger)
Anticonvulsants
Sulfonamides
Allopurinol
Treatment
Withdrawal of suspect drug as soon as possible
If many drugs are incriminated, stop all nonessential drugs
if the suspect drug is essential, substitute with
another that does not cross-react
For mild drug eruption, start topical steroid and
systemic antihistamines
Start systemic steroid in case of SJS/TEN and
DRESS
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