Chapter 36 Disturbances of Pigmentation

Chapter 36 Disturbances of Pigmentation
JoAnne M. LaRow. D.O.

Melanin = primary pigment producing brown coloration
Tyrosine – tyrosinase –melanin- this occurs in the melanosomes of melanocytes Then the melanosomes are transferred from the melanocyte to a group of keratinocytes called the epidermal melanin unit Variations in skin color is related to the number of melanosomes, the degree of melanization, and the distribution of the epidermal melanin unit

Pigmentary Demarcation Lines
Can be divided into five categories: Group A- lines along the outer upper arms with variable extension across the chest Group B-lines along the posteromedial aspect of the lower limb Group C-Paired median or paramedian lines on the chest, with midline abdominal extension Group D-medial, over the spine Group E-bilaterally symmetrical, obliquely oriented, hypopigmented macules on the chest

Pigmentary Demarcation Lines
More than 70% of blacks have one or more lines These are much less common in whites Type B lines often appear for the first time during pregnancy

Normal Pigmentation Normal skin pigmentation is influenced by:
-the degree of vascularity -the amount & location of melanin -the presence of carotene -the thickness of the horny layer

Melanin Production The amount produced is dependent on: -genetics
-the amount and the wavelengths of ultraviolet light received -the amount of melanocyte-stimulating hormone(MSH) secreted - the effect of melanoccytestimulatingg chemicals like furocoumarins (psoralens)

Hemosiderin Hyperpigmnetation
Pigmentation due to deposits of hemosiderin occurs in: -purpura -hemochromatosis -hemorrhagic diseases -stasis ulcers ** difficult to distinguish from postinflammatory dermal melanosis clinically

Postinflammatory Hyperpigmentation
Any inflammatory condition can cause either hypopigmentation or hyperpigmentation Also may be a complication of chemical peels, dermabrasion, laser therapy, or liposuction Histologically, there is melanin in the upper dermis and around upper dermal vessels, located primarily in macrophages (melanophages) Find histology Lever

Postinflammatory hyperpigmenation
Postinflammatory hyperpigmentation following resolution of lymphocytoma cutis on the cheek of a black child

Industrial Hyperpigmentation
Occurs in coal miners, anthracene workers, pitch workers, etc Pigmentation of the face may occur from the incorporation in cosmetics of derivatives of coal tar, petrolatum, or picric acid, mercury, lead, bismuth, or furocoumarins (psoralens) Look for image of industrial hyperpigmentation

Systemic Diseases Syphilis, malaria, pellagra, and diabetes
Addison’s disease- diffuse melanosis pronounced in the axillae and palmar creases, and nipples and genitals, and buccal mucosa Diabetes produces diffuse bronzing of the skin ** patients with virilizing adrenal tumors usually develop hyperpigmentation and hypertrichosis Examples of bronze diabetes & addison’s diseaes

Systemic Diseases Vitamin B12 deficiency Kwashiorkor
Nelson’s syndrome (a pituitary MSH-producing tumor) Pheochromocytoma Hemochromatosis Amyloidosis Scurvy Pregnancy Menopause Porphyria cutanea tarda Vitamin B12 deficiency Kwashiorkor Vitamin A deficiency Primary biliary cirrhosis (triad= hyperpigmentation, pruritis, xanthomas)

Hemochromatosis Characterized by:
Gray-brown mucocutaneous hyperpigmentation Diabetes mellitus hepatomegaly Usually are present: Cirrhoisis Hypogonadism Liver cirrhosis

Hemochromatosis Skin pigmentaion is usually generalized
But, more pronounced on face, extensor aspect of the forearms, backs of the hands, and the geniocrural area Iron is deposited in the skin Iron is present as granules around blood vessels and sweat glands and within macrophages The actual pigmentation is caused by increased basal-layer melanin Mucous memebranes are pigmented in up to 20% of patients Koilonychia is present in 50% Localized ichthyosis in 40% Alopecia is common

Hemochromatosis Dx: Elevated plasma iron and IBP
High serum ferritin without an obvious cause should prompt investigation for both hemochromatosis and PCT Etiology is either an inborn error of metabolism or excessive number of blood transfusions AR gene for heredity hemochromatosis is linked to the HLA-A locus on chromosome 6p Occurs mostly in men in their sixties Women who have genetic hemochromatosis can have full phenotypic expression Extremely rare in the young Neonatal hemochromatosis has been associated with intrauterine infections ie cytomegalovirus Adults with hemochromatosis are susceptible to Yersinia enterocolitica

Hemochromatosis-tx Phlebotomy until satisfactory iron levels are found
Extracorporeal chelation has also been used successfully Associated DM requires medical tx Long-term complications are cirrhosis and then hepatomas

Melasma Brown patches, sharply demarcated, typically on the malar prominences and forehead The three clinical patterns are: centrofacial, malar, mandibular Increased pigment may simultaneously occur around the nipples and external genitalia Tends to affect the darker-complected It may also be found on the forearms Occurs at pregnancy and at menopause It may also be seen in ovarian disorders and other endocrine disorders Most frequently 90% of the time seen in women, 10% in men

Melasma Tx- avoid sunlight, and a complete sun block with broad-spectrum UVA coverage should be used daily Kligman’s formula (Triluma) > then 4% hydroquinone may be needed Side effects of this is ochronosis and satellite pigmentation Jessner’s solution, glycolic acid peels,azelaic acid, kojic acid, and cystamine and buthionine sulfoximine are other options Strong association with the use of birth control pills or dilantin Discontinuing the contraceptives rarely clears the pigmentation, and it may last for years after discontinuing them. Melasma of pregnancy usually clears within a few months of delivery

Melasma

Acromelanosis Progressiva
AKA acropigmentation A progressive pigmentary disorder first described in a Japanese infant Characterized by diffuse black pigmentation on the dorsum of all the fingers and toes Pigmentation became progressively more widespread and more pigmented By age 4 or 5 the perineum, extremities, and areas of the head and neck were involved Epileptiform seizures occurred History revealed consanguinity

Pigmented Anomalies of the Extremities
Acropigmentation of Dohi Found to affect individuals from Europe, India, Caribbean First described in Japan in 12 patients AKA dyschromatosis symmetrica hereditaria or symmetrical dyschromatosis of the extremities Patients develop progressive pigmented & depigmented macules Often mixed in is a reticulate pattern Many believe this to be a variation of acropigmentation of Kitamura

Reticular Pigmented Anomaly of the Flexures
Clinically it looks smooth Pigmententation is reticular; at the periphery, discrete, brownish black macules surround the partly confluent central pigmented area Typically, axillae, inframmary folds, and intercrural folds are involved There are frequently pits, sometimes pigmented , about the mouth A rare pigmentary adult-onset disorder AKA Dowling-Degos disease or dark dot disease Should be considered whenever acanthosis nigricans is in the differential & pt is not obese and is known not to have any internal malignancy

Reticular Pigmented Anomaly of the Flexures
It begins age 20 to 30 yrs and progresses gradually Unknown etiology AD with variable penetrance and expressivity, and delayed onset Many authors believe it is a spectrum of reticulate acropigmentation of Kitamura Another manifestation of this disorder is familial-rocacea-like dermatitis with warty keratotic plaques on the trunk and limbs There is no treatment

Histology Distinctive elongation, tufting, and deep hyperpigmentation of therete ridges, with protrusion of similar tufts even from the sides of the follicles

Reticulate Acropigmentation of Kitamura
AD Characterized by linear palmar pits and pigmented macules 1-4 mm in diameter on the volar and dorsal aspects of the hands and feet One report of a pt with bony abnormalities consisting of absence of terminal phalanges of the second, third, and fourth toes Some tx success has been reported using axelaic acid ointment

Dermatopathia Pigmentosa Reticularis
Consists of a triad of generalized reticulate hyperpigmentation, noncicatricial alopecia, and onychodystrophy Other associations: adermatoglyphia, hypohidrosis or hyperhidrosis, palmoplantar hyperkeratosis, and nonscarring blisters on dorsa of hands and feet. An autosomal dominant inheritance pattern has been reported.

Dermatopathia Pigmentosa Reticularis

Transient Neonatal Pustular Melanosis
Histologically, there are intracorneal or subcorneal aggregates of predominantly neutrophils, but eosinophils may also be found Dermal inflammation is composed of an admixture of neuts and eos Differential dx: ETN, neonatal acne, & acropustulosis of infancy Infants develop 2- 3mm macules, pustules, and ruptured pustules at birth, predominantly involving the face Pigmentation may last for weeks or months after the pustules are healed Histology image needed

Transient Pustular Neonatal Melanosis

Transient Neonatal Pustular Melanosis

Peutz-Jeghers Macules may also occur around the mouth, on the central face, backs of the hands, especially the fingers, and on the toes and tops of the feet. Associated polyposis involves the small intestine preferencely But, hamartomatous polyps of the stomach and colon may occur Symptoms of hamhartomas of the small intestine may cause repeated bouts of abdominal pain and vomiting, and intussusception Characterized by hyperpigmented macules on the lips and oral mucosa and polyposis of the small intestine Dark brown or black macules appear typically on the lips, especially the lower lip, in infancy or childhood Similar lesions may appear on buccal mucosa, tongue, gingiva, and genital mucosa

Peutz-Jeghers Syndrome
Cosmetic tx of labial macules has been accomplished with the use of a 694-mm ruby laser incidence of malignancy within the polyps is 2-3% Incidence of GI malignancy is low, but increased incidence of other kinds of cancer-breast, and gynecologic malignancies in women Syndrome is inherited and transmitted as a simple mendelian dominant trait Sporadic noninherited cases may occur The gene (STK11) has been localized to 19p13.3 19p13.3 is believed to be a tumor suppressor gene

Peutz-Jeghers Syndrome
A protein-losing enteropathy may develop and is associated with the degree of intestinal polyposis Onset is after age 30 yrs Sporaically occurring, benign condition Hypogeusia is the dominant initial symptom Diarrhea and ectodermal changes may follow 75% of cases have been reported in Japan Cronkhite-Canada syndrome should be considered in dx Characterized by melanotic macules on the fingers and gastrointestinal polyposis Also generalized , uniform darkening of the skin, extensive alopecia, and onychodystrophy The polys that occur are usually benign adenomas and may involve the whole GI tract

Peutz-Jeghers syndrome
Lip lentigenes in an adolescent with Peutz-Jeghers syndrome

P-J syndrome

Pathology

Reihl’s Melanosis Photosensitivity, phototoxic dermatitis
Begins with pruritis, erythema, and pigmentation, gradually spreads, then becomes stationary Melanosis occurs mostly in women and develops over months Characteristic feature is spotty light to dark brown pigmentation Most intense on the forehead, malar regions, behind the ears, on the sides of the neck, on other sun-exposed areas Also circumscribed telangiectasia and temporary hyperemia

pathogenesis Sun exposure following perfume or cream
A photocontact dermatitis One report of a positive patch test results to lemon oil, geraniol, and hydroxycitronellal Has been reported in patients with AIDS and Sjogren’s syndrome No good treatments The cause of the sensitivity needs to be determeined Hyperkeratosis and pigmentation disappear spontaneously

Tar Melanosis An occupational dermatosis occurring among tar handlers after years of exposure Severe, widespread itching develops, followed by reticular pigmentation, telangiectases, and a shiny appearance of the skin There is a tendency for hyperhidrosis Small, dark, lichenoid, follicular papules become profuse on the extremities, namely the forearms Bullae are sometimes observed Represents a photosensitivity or phototoxicity induced by tar

Familial Progressive Hyperpigmentation
AD inheritance Histologically- increase in melanin in the basal cell layer, especially at the tips of the rete ridges Pigmented granules are scattered diffusely throughout the epidermal layers Differentiated from other hyperpigmentations by presence of bizarre, sharply marginated patterns of hyperpigmented skin Familial Progressive Hyperpigmentation Characterized by patches of hyperpigmentation, present at birth, increasing in size and number with age Hyperpigmentation appears in the conjunctivae and the buccal mucosa over time Eventually large portions of skin and mucous membranes become involved

Universal Acquired Melanosis(Carbon Baby)
Ruiz-Maldonado reported a case of a Mexican child, born white, who progressively became black Developed pigmentation of the palms, soles, mucous membranes EM showed a negroid pattern in the melanosomes of the epidermal melanocytes and keratinocytes Melanocytes were not increased in number

Zebralike Hyperpigmentation
Alimurung et al reported an unusual pattern of hyperpigmentation in a black male infant with congenital defects (ASD, dextrocardia, auricualr atresia, deafness. And growth retardation) Hyperpigmenation was linear and symmetrical, involving the trunk and extremities Increased number of melanocytes in the bands of hyperpigmentation Pigmentary anomaly fades with time spontaneously May be a varient of incontinentia pigmenti

Periorbital Hyperpigmentation
1.) Familial periorbital melanosis (AD) Usually involves all four eyelids, may extend to involve the eyebrows and cheeks 2.) Erythema dyschromicum perstans is a rare cause 3.) Familial dark circles around the eyes, frequently seen in individuals of Mediterranean ancestry

Metallic Discolorations
Pigmentation from deposition of fine metallic particles in the skin Metal may be carried to skin from the blood stream or may permeate into it from surface applications

Argyria Local tx with a silver-containing product may produce argyria
Examples: conjunctivae, from eye drops; a wound from sulfadiazine cream, earlobes from silver earings; and from silver acupuncture needles Can also occur from occupational exposure, usually siversmiths In localized exposures, the appearance may be separated by many years from the exposure Localized or widespread slate-colored pigmentation Due to silver in the skin Most noticeable in parts exposed to sunlight Tissue silver may stimulate melanocytes Initially discoloration is hardly perceptible, having only a faint blue color, but a slate-gray color develops with time

Histology Systemic and localized argria have the same features
Normal appearing skin under low power Fine black granules in the basement zone of the sweat glands,blood vessel walls, d-e junction, and arrector pili muscles Unstained biopsy section by darkfield illumination demonstrates silver granules outlining basement membrane of the epidermis and the eccrine sweat glands

Bismuth Rarely associated with deposition of metallic particles in gums when used IM or orally Also known as the bismuth line Presence of stomatitis or peridontitis increased the risk Generalized cutaneous discoloration, in addition to oral mucous membrane and conjunctival pigmentation resembling argyria has occurred but has not be reported in the last 50 years

Lead Chronic lead poisoning can produce a “lead hue” with lividity and pallor Deposit of lead in the gums may occur and is known as the “lead line”

Iron In the past, soluble iron compounds were used in the treatment of allergic contact dermatitides In eroded areas iron was sometimes deposited in the skin, like a tattoo Use of Monsel’s solution can produce similar tattooing

Gold Chrysiasis may be induced by parenteral administration of gold salts, usually for the treatment of rheumatoid arthritis More commonly recognized in white patients A mauve, blue, or slate/gray pigmentation develops initially on the eyelids, spreading to the face, dorsal hands, and other areas Severity is related to the total dose received, rare < a dose of 20 mg/kg of elemental gold Pigment is accentuated in light-exposed areas, and sun protected areas do not demonstrate gold Localized chrysiasis has been induced by the Q-switched ruby laser tx in a patient on parental gold therapy

Mercury Mercurial pigmentation in the skin is rare, especially since the use of mercurials has been strictly controlled Most common presentation is subcutaneous nodules that result from accidental implantation of elemental mercury from a thermometer into skin

Canthaxanthin Orange-red pigment canthaxanthin is present in many plants ( notably algae and mushrooms) and in bacteria. Crustaceans, sea trout, and feathers When ingested for the purpose of simulating a tan, its deposition in the panniculus imparts a golden orange hue to the skin Stools become brick red and the plasma orange, and golden deposits appear in the retina

Dye Discoloration Blue hands from accidental dyeing were reported by Albert in 1976 A man’s hands were dyed as a result of warming them in his armpits while wearing a new blue flannel shirt The dye was insoluble in water, but soluble in sweat

Rubeosis A rosy coloration of the face occurring in young people with uncontrolled diabetes mellitus May be associated with xanthochromia to produce a “peaches and cream” complexion

Vitiligo Usually begins in childhood or young adulthood
50% of cases begin before age 20 Prevalence ranges from 0.5% to 1% Females are disproportionately represented among patients seeking medical care, it is not known if it is actually more common in females or simply because they more often bring it to their physicians attention

Clinical Features An acquired pigmentary anomaly of the skin
Manifested by depigmented white patches surrounded by a normal or a hyperpigmented border There may be intermediate tan zones or lesions , halfway between the normal skin color and depigmentaton-so-called trichrome vitiligo Hairs in vitiliginous areas usually become white also Rarely, the patches may have a red, inflammatory border Patches are of various sizes and configurations

Types Localized or focal(including segmental) Generalized Universal
Acrofacial

Vitiligo Generalized is the most common Involvement is symmetrical
Most commonly involving the face, upper chest, dorsal aspects of the hands, axillae, and groin Tendency for skin around orifices to be affected (eyes,nose, mouth, ears, nipples, umbilicus, penis, vulva, anus) Lesions also favor areas of trauma (elbows and knees)

Generalized Vitiligo Involvement of perineal and inguinal skin
Note the distinct borders

Acral Vitiligo

Symmetric, Acral Vitiligo
Left: pre-PUVA treatment Right:same pt shows perifollicular pattern of repigmentation during PUVA therapy

Segmental Vitiligo Rapidly progressing segmental vitiligo

Segmental Vitiligo Segmental vitiligo of the eyebrow and eyelashes

Segmental Vitiligo Segmental vitiligo on the arm , neck, and chest
Note areas of spontaneous follicular repigmentation Left upper back with partial spontaneous repigmentation

Universal Vitiligo Applies to cases where the entire body surface is depigmented

Focal Vitiligo May affect one nondermatomal site
Or asymmetrically affect a single dermatome This form is treatment resistant, has an earlier onset, and is frequently associated with other autoimmune phenomena It represents 5% of adult vitiligo and 20% of childood vitiligo Trigeminal area is most commonly affected

Acrofacial Vitiligo Type affecting the distal fingers and the facial orifices

Vitiligo Local loss of pigment may occur around nevi and melanomas, the so-called halo phenomenon Vitiligo-like leukoderma occurs in 1% of melanoma patients In those previously dx with melanoma, it suggests metastatic disease Paradoxically, patients who develop leukoderma have a better prognosis than patients without it Halo nevi are more common in patients with vitiligo Lesions are hypersensitive to UV light and burn easily when exposed to the sun

Ocular abnormalities are increased in patients with vitiligo
Iritis and retinal pigmentary abnormalities 8% of pts with idiopathic uveitis have vitiligo or poliosis Most frequent associations are with other “autoimmune” diseases((IDDM, pernicious anemia, Hashimoto’s thyroiditis, Graves’ disease, Addison’s disease, and AA) Vitiligo occurs in 13% of pts with the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) Familial aggregation is seen- up to 30% of vitiligo pts have an affected relative-it is not inherited as AD or AR trait, but has a multifactorial genetic basis

Childhood Vitiligo Shows an increase in segmental presentation
More frequent autoimmune or endocrine anomalies High incidence of premature graying in females Poor response to PUVA therapy

Vitiligo Completely depigmented oval ivory white areas with convex hyperpigmentated borders

Vitiligo Vitiligo with depigmentation of the lips

Henne Induced Vitiligo

Occupational Vitiligo
All the intermediates in the biosynthesis of melanin are phenolic compounds, therefore postulated that accumulation of these within the melanocyte may damage or kill the cell. Clinical pattern may be similarto vitiligo, but lesions tend to be concentrated in areas of contact with the incriminated substance Thiols, phenolic compounds, catechol, derivatives of catechol, mercaptoamines, and several quinones produce depigmentation Seen in pts who work in rubber garments or wear gloves containing an antioxidant, monobenzyl ether of hydroquinone

Occupational Vitiligo
Many phenolic compounds can produce leukoderma, with or without antecedent dermatitis Examples: paratertiary sulfhydryls; monobenzyl ether of hydroquinone One source is phenolic antiseptic detergents used in hospitals Adhesives and glues containing them may be found in shoes, wristbands, and adhesive tape, and rubber products used in brassieres, girdles, panties, or condoms may also be at fault Self-sticking bindis (the cosmetic used by many Indian woman on the forehead) has been reported to induce leukoderma from the adhesive material Electrocardiograph electrodes may cause similar hypopigmented spots

Chemical Depigmentation
Chemical depigmentation due to a germicidal detergent Pts usually improve with discontinuation of the offending agent

Pathogenesis Three possible mechanisms have been proposed as inducing vitiligo are autoimmunity, neurohumoral factors, and autocytotoxicity No mechanism has been conclusively proven

Histology There is complete loss of melanocytes
Usually there is no inflammatory component

Differential Morphea Lichen sclerosis Pityriasis alba
Tinea versicolor tertiary pinta

Treatment Fair-skinned pts may manage their disease with sunblock
Sun protection is mandatory in all pts with vitiligo because of the loss of protection from UV radiation in the depigmented skin Topical steroids may be useful on focal or limited lesions Mid to super high-potency steroids are often required on trunk and acral lesions with the strength tapered as the lesions respond Spontaneous repigmentation occurs in no more than 15% to 25% of cases Response is slow PUVA may actually worsen the appearance initially by pigmenting surrounding skin Cover-up strategies(topical dyes, make-up, self-tanning creams)

Systemic steroids lead to temporary repigmentation, this is usually lost as the steroidal agents are tapered PUVA therapy is the most common treatment for generalized vitiligo Topical application of 8-methoxypsoralen at a concentration of 0.05% to 0.01%, followed by UVA exposure Topical PUVA is used for focal or limited lesions Inadverrtent burns with blistering are frequent during tx Treatment Trioxsalen, at a dose of up to 20-40mg, is taken a few hours before natural sun exposure Risk of phototoxicity is low,so this can be done at home Ocular protection must be worn from the ingestion of the drug through the whole tx day

Most commonly, 8-methoxyporalen is used
Initially tx is QOD(because of the delayed erythema of PUVA), increased to QD once dose is defined 1hr to 30 mins before UVA exposure , 8-methoxypsoralen 0.5mg/kg is ingested Initial UVA dose is 1 or 2 J/cm squared, which is gradually increased; 5-MOP has an aefficccacy equal to that of 8-MOP and less risk of phototoxicity Two-three tx’s/week are done 20% of pts total repigmentation occurs;30% to 40% have partial response Acral, periorificial, and segmental lesions respond less well Darker-skinned pts have a better response, since they tolerate higher UV doses Repigmentation may begin after tx’s;significant improvement may take tx’s

If there is no follicular repigmentation after 3-6 months or approx 50 tx’s PUVA should be abated
CI to PUVA: photosensitivity, porphyria, liver disease, SLE Surgical tx’s can be applied to limited lesions if all other tx modalities have been exhausted Epidermal grafting, autologous minigrafts, and transplantation of cultured and noncultured melanocytes Phenylalanine/UVA(PAUVA) is much less effective than PUVA UVB tx alone with 311-nm irradiation is associated with a higher rate of acute phototoxicity but may be successful UVA plus topical steroids is superior to either agent alone, but is successful only 24-36% of the time after 9 months

If > 50% of the body surface area is affected by vitiligo, the pt can consider depigmentation
This tx is permanent Monobenzone 20% is applied BID for 3-6 months to residual pigmented areas Up to 10 months may be required One in six pts will experience acute dermatitis, usually confined to the still-pigmented areas

Vitiligo Partial repigmentation of lesions of vitiligo on the leg of a 14-year-old child at the end of the summer of sun exposure

Vitiligo Partial repigmenation of vitiligo following psorralen-ultraviolet light (PUVA) therapy

Vitiligo Permanent repigmentation after 2 years of photochemotherapy (tripsoralen followed by sunlight exposure)

Vogt-Koyanagi-Harada Syndrome
Characterized by bilateral uveitis, symmetrical vitiligo, alopecia, white scalp hair, eyelashes and brows(poliosis, and dysacousia(diminished hearing) Occurs in thirties Initial or meningoencephalitic phase occurs with prodromata of fever, malaise, headache, nausea, and vomiting Also may have psychosis, paraplegia, hemiparesis, aphagia, and nuchal rididity Recovery is usually complete

VKHS Second phase(ophthalmic-auditory stage) is characterized by uveitis, dreased visual acuity, photopobia, and decreased hearing(50%) The convalescent phase begins 3weeks to 3 months after it begins to improve

Alezzandrini’s Syndrome
Extremely rare syndrome characterized by a unilateral degenerative retinits This is followed several months later by ipsilateral vitiligo on the face and ipsilateral poliosis Deafness may also be present

Alezzandrini’s Syndrome

Leukoderma Postinflammatory leukoderma may result from inflammatory dermatoses ie: Pityriasis rosea, psoriasis, herpes zoster, secondary syphilis, and morphea, sarcoidosis, tinea versicolor, mycosis fungoides, scleroderma, and pityriasis lichenoides chronica, and leprosy Other causes: burns, scars, postdermabrasion, and intralesioal steroid injections

Leukoderma Postinflammatory hypopigmentation in a 4-month-old black child with atopic dermatitis

Leukoderma Postinflammatory hypopigmentation following resolution of guttate psoriasis

Pityriasis alba Ill-defined hypopigmented oval patches are generally seen on the face, upper arms, neck, and shoulders of affected persons It can be differentiated from vitiligo by its fine adherent scale, partial hypopigmentation, and distribution

Pityriasis alba White, slightly scaly patches with indistinct borders on a child’s cheek

Postinflammatory hypopigmentation

Albinism A partial or complete congential absence of pigment in the skin, hair, and eyes (oculocutaneous albinism), or the eyes alone (ocular albinism) Cutaneous phenotype of the various forms is broad, but the ocular phenotype is reasonably constant in most forms The ocular phenotype includes decreased visual acuity, nystagmus, pale irides that transilluminate, hypopigmented fundi, hypoplastic foveae, and lack of stereopsis

Albinism This pt has light skin, yellowish white hair, and a lack of pigmentation in nevi

Oculocutaneous Albinism 1
OCA 1 results from mutations in the tyrosinase gene Affected pts are homozygous for the mutant gene or are compound heterozygotes for different mutations in the tyrosinase gene AR Two forms: 1) OCA 1A & OCA 1B (indistinguishable at birth) OCA 1 is most severe with complete absence of tyrosinase activity and complete absence of melanin in the skin and eyes Visual acuity is decreased to 20/400 OVA 1B tyrosinase activity is reduced but not absent. Pts may show increase in skin,hair, eye color with age and can tan

OCA 1 OCA 1B was originally called “yellow mutant” albinism
Temperature sensitive OCA (OCA 1-TS) results from mutations in the tyrosinase gene that produce an enzyme with limited activity < 35 degrees C and no activity below this temp. pts have white hair, skin, andeyes at birth, at puberty dark hair develops in cooler acral areas

Top:albinism with white hair, pale skin, and translucent irides
Bottom:ophthalmoscopic view of a pt with albinism demonstrates a pale fundus, poor macular development, and prominent choroidal vasculature

Prevalence of 1:15,000 Pts were named “tyrosinase-positive” albinos AR and mutations occur in the P gene P gene codes a membrane transport protein that is present in the melanosome membrane Cutaneous phenotype of OCA 2 pts is broad, ranging from nearly normal pigmentation to virtually no pigmentation Pigmentation increases with age, and visual acuity improves with age Prader-Willi and Angelman syndromes are caused by deletions in the P gene; 1% of pts with these syndromes also have OCA 2

AR-caused by mutations in the tyrosine-related protein 1 (TRP-1), located on chromosome 9 OCA 3 has been described only in black pts and is characterized by light brown hair, light brown skin, blue/brown irrides, nystagmus, and decreased visual activity Brown rather than black melanin is formed

Ocular Albinism There are multiple forms of ocular albinism
OA 1 may be present with lighter than expected skin It is X-linked Female carriers have “mud-splattered” fundi Macromelanosomes are found in the skin, so skin bx may be a helpful tool Many cases of AR ocular albinism have been reclassified as OCA 1 or OCA 2

Syndromes Associated with Albinism
Chediak-Higashsi Syndrome Hermansky-Pudlak Syndrome Griscelli Syndrome(partial albinism with immunodeficiency) Elejalde Syndrome Cross-McKusick-Breen Syndrome Cuna Moon Children

Classification of Oculocutaneous Albinism

Selenium Deficiency Selenium deficiency in the setting of total parental nutrition can lead to pseudoalbinism Skin and hair pigmentation return to normal with supplementation

Waardenburg’s Syndrome
Four genotypic variants exist: Types 1 & 3 are caused by mutations in the PAX gene on chromosome 2 Type 2 is caused by mutations in the MITF gene on chromosome 3, and type 4 due to mutations in the ENDRB gene on chromosome 13 Pts have features of piebaldism, with white forelock, hypopigmentation, premature graying, synophrys, congenital deafness, a broad nasal root, and ocular changes including heterochromia irides Apparently, melanoblasts fail to reach the target sites during embryogenesis

Piebaldism Rare, AD with variable phenotype, presenting at birth
White forelock, patchy absence of skin pigmenation Depigmented lesions are static and occur on the anterior and posteroir trunk, mid upper arm to wrist, mid-thigh to mid-calf, and shins A characteristic feature is the presence of hyperpigmented macules within the areas of lack of pigmentation and on normal skin

Piebaldism

Piebaldism Segmental white patch on the neck with a tuft of white hair present from birth

Piebaldism White forelock and patch of unpigmented skin in a young girl with piebaldism

Piebladism The white forelock arises from a triangular or diamond-shaped midline white macule on the frontal scalp or forehead The medial portions of the eyebrows, and eyelashes may be white Histologically, melanocytes are completely absent in the white macules Etiology is a mutation in the c-kit protooncogene Phenotypic differences seen in families is caused by different locations of mutations in the gene The white lesions may respond to surgical excision

Idiopathic Guttate Hypomelanosis
AKA leukopathica symmetrica progressiva Very common aquired disorder affecting women more frequently than men Usually occurs after age 40 Lesions occur on the shins and forearms; are small (6 or 8mm), rarely become very numerous ( a dozen or two at most), and never occur on the face or trunk Lesions are irregularly shaped and very sharply defined, like depigmented ephelides, and are only of cosmetic significance

Idiopathic Guttate Hypomelanosis

Chapter 36 Disturbances of Pigmentation

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