Dyschromie

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introducedon :

  • Changing the normal skin color, not erasing is under mechanical action, due, most of the time, a disorder of melanogenesis (Overload melanin or disappearance)
  • Color normal from the skin :

➢ Depends on the skin type of the subject and sun exposure, so, We are talking about :

Color constitutive : which is a reflection of the melanin pigmentation genetically determined

Color inductive : by tanning after sun exposure

➢ At the same topic, pigmentation varies anatomical regions : areas usually exposed to the sun and the folds and genitalia are naturally pigmented

➢ The color of the skin due mainly to the presence of a pigment called "melanin" whose primary role is to protect the basal layers of the skin against ultraviolet

OutPPL :

  • Macules dyschromiques :

Macules pigmented : they are due to accumulation of pigment in the epidermis or

in the dermis

melanin : natural pigment of the skin

localized : chloasma (mask of pregnancy), spots café-au-lait

generalized : melanodermia Addison's disease

Pigment Non-melanoma : usually metal (tattoo, iron in hemochromatosis)

Macules achromiques : they are due to a decrease (macule hypochromique) or absent (macule achromique) melanocytes of the skin and / or melanin secretion thereof. They appear as clear spots (example : vitiligo et pityriasis versicolor achromique

  • Analysis semiotic a trouble pigment : it includes elements that interrogation should be sought systematically, because they are not always mentioned spontaneously by the patient. He try to clarify : the character acquired or congenital, date of onset, the possible role of sunlight,  the treatment undertaken and results,  the existence of an inflammatory phase preceding the pigmentary disorder, various topical used before the onset of dermatitis, the patient's systemic treatments
  • Exam clinique :

➢ The color of a hyperchromia (brown, noir, bluish gray ...) is an important element semiotic :

▪ A brown brown-black to match, most of the time, a melanin overload (hypermelanosis) located in the epidermis

▪ A gray or bluish gray translated, most of the time, dermal hypermelanosis or exogenous pigments overload, normally not present in the skin

➢ Front hypochromia, must specify whether it is total or partial and the existence of another elementary lesion (erythema, papule…)

Heperpigmentations :

  • freckles (freckles) :  hyperpigmentations maculeuses,  localized,  short (a few millimeters),  light brown tint,  frequent in subjects with blue eyes red, usually appearing in childhood, are located on the face and exposed parts, permanent but their number increases with age and color deepens after sun exposure, topics bearing profuse freckles generally exhibit marked photosensitivity

➢ The freckles correspond to hypermélaninose (increased synthesis of melanin)

  • Lentigines : hyperpigmented macules small (1-3 mm), which are distinguished by their freckles darker shade (brown or black) and their lack of change after sun exposure, typically regional, they can be distributed over the entire surface of the seed coat and / or mucous membranes, can appear in childhood or later in life, sometimes integrate in complex multisystem syndromes term

➢ Lentigines correspond to hypermélanocytose (increase in the number of melanocytes)

  • stains coffee at-milk : macules brun clair, homogeneous color, round or oval, at regular or rugged, whose size can vary from a few centimeters to several tens of centimeters, few, localize willingly on the chest, the backbone and sometimes members, topography can be unilateral
  • stains Mongolian : bluish gray macules, ranging in size from a few millimeters to several tens of centimeters, common in Asians and blacks, present at birth, they disappear clinically during childhood, topography : lower back and buttocks
  • melasma (chloasma) : hyperpigmentation sitting on the upper face, respecting the edge of the scalp, usually bilateral, non-symmetrical, inhomogeneous color (varying from yellow ocher to dark), be accentuated in summer, two etiological factors : hormonal stimulation (pregnancy, estrogen, progestin), stimulation by ultraviolet. During pregnancy, hyperpigmentation also appears on the areola of the breast, abdominal white line, scars and genital mucosa
  • Hyperpigmentation post-inflammatory : hyperpigmented spots remaining that persist after healing of various dermatoses, in that case, pigmentary disorder is not the consequence of a primary involvement of melanocytic system
  • Pigment original  exogenously :  discolorations resulting from exogenous :  transcutaneous penetration accidental or voluntary (tattoo, subcutaneous or intramuscular injection) substances nonabsorbable, absorption or systemic poisoning of certain metals or drugs

Argyrie :  Money absorbed per prolonged bone or injected can cause mottled hyperpigmentation of the integument, hue slate gray metallic luster, topography diffuse but mostly open areas : oral mucosa, rhinopharyngées, eye or nails may be affected. The argyria has, most of the time, an occupational (jewelers,  photographies,  silver nitrate manufacturers),  therapeutic origin has become rare

  • hypermelanosis metabolic :

hemochromatosis : diffuse skin hyperpigmentation, shade of brown slate gray with a metallic sheen, sometimes intense, almost black, it gives the skin a dirty badly washed appearance, predominates discoveries regions and folds, cutaneous melanodermia also occurs during secondary hemochromatosis by excessive intake of iron (transfusion…)

Sickness from Wilson : hyperpigmentation of the lower limbs

melanodermia  uremic  from  inadequate  kidney :  hyperpigmentation diffuse, greyish, dull, more pronounced on exposed areas and respecting the mucous membranes

  • hypermelanosis endocrine :

Sickness d’Addison : melanodermia broadcasts more pronounced on exposed parts and / or naturally pigmented,  on the areas subjected to repeated rubbing,  to trauma, oral mucosa (slaty spots), the achievement of the genital mucosa and conjunctiva is common

Tumors visceral with secretion ectopique d’ACTH or from MSH

Other endocrinopathies : syndrome de Cushing, acromegaly, phéochromocytome

Dyschromie 1Hypopigmentations :

  • Leukoderma is a localized or diffuse lightening skin, much easier to see that the skin is pigmented, it can be the result of a lack of melanin pigment which has just result from :

➢ Decrease in number of melanocytes or complete disappearance

➢ Failure synthesis or transfer of melanin

➢ localized Vasoconstriction

➢ white substance Deposit

  • Albinismes oculo-cutaneous :  refers specifically genetic diseases involving diffuse Hypomelanosis and eye characteristic manifestations, they are due to a defect of melanin synthesis by melanocytes in the skin, appendages and eye. The diagnosis is clinical

In the forms severe : the diagnosis is obvious : hair and the hair is snow white, blue eyes, dew white skin, no tan, the skin is very sensitive to ultraviolet with a major risk of skin cancer,  absence of pigmented skin lesions

In the forms less severe : the hair is blond or light brown straw, blue eyes with light brown, the skin is able to tan moderately, there may be freckles, lentigines and slightly pigmented nevus. Diagnosis ècomparaison with parents and siblings +++

  • Vitiligo : white blotches,  spread,  whose confluence may cause, to the extreme, generalized depigmentation, family in more than one third of cases, susceptibility genes with vitiligo are unknown, World frequency of about 1%, both sexes are equally affected, can appear at any age, but expressed most often in young adults during the second and third decades of life, role of psycho trauma or physical +++

Clinique :

Lesion  elementary :  macule achromique,  uniform color,  milky white, devoid of melanin (Wood light examination), of various shapes and sizes, always convex edges,  normal surface,  limited by the often irregular contours but distinct, sometimes highlighted by a border hyperpigmented, no functional signs or inflammatory signs but +++ photosensitivity, hair, hairs, eyelashes and eyebrows can be depigmented. The hair depigmentation in vitiligo lesions is also a predictor of poor treatment response

Topography : often unilateral and bilateral start, often symmetrical, body parts are most commonly affected : normally pigmented areas most (axilla,  external genitalia),  uncovered areas, exposed to light,  suburban areas orificial,  bony prominence areas (knees, shins, malleolar regions, iliac spines, sacred areas), areas exposed to repetitive strain injuries (flanges underwear, belt) èphénomène de Koebner

Extension of the injury : there are generalized vitiligo (in extreme cases, can invade the entire integument : vitiligo universalis), of localized vitiligo, sometimes segmental topography, unilateral

Association : with several diseases, especially autoimmune diseases (thyroiditis, pernicious anemia ...)

Evolution : capricious and unpredictable, repigmentation often occurs from the hair follicles giving a speckled appearance

Diagnostic : exclusively clinic, the light examination of Wood is very useful for detecting hypomélanotiques lesions in subjects with light skin,  biopsy for histopathological examination is only practiced under research, it shows a lack of melanocytes in the lesional skin

  • Hypomélanoses original infectious : pityriasis versicolor represents the bulk of achromatic fungal
  • Hypomélanoses post-inflammatory : secondary depigmentation associated with systemic lupus erythematosus, psoriasis, Eczema, to eczematides (this list is not exhaustive), the diagnosis is always easy because the lesions typical of causal affection are constantly found either by examination or by clinical examination
  • leucodermas through agents physical and or chemical : Table clinicopathological is close vitiligo, melanocytes are vulnerable to most physical attacks (rayon X, UV, burns, cold) and various mechanical damage

Traitement :

  • hypermelanosis :

eviction : Removal of the pathogen is the first therapeutic measure to be taken : Removal prolonged sun exposure or use of creams for UV screens

Agents depigmentation : various products have been proposed in therapy to discolor the skin hyperpigmentation, it is oxidizing agents (peroxides ...) or reducing

Lasers : they have been proposed for the treatment of pigmented lesions and tattoos

  • Hypomélanoses : when an etiological factor can be identified, the removal of the pathogen is the first step in :  eviction of a chemical depigmentation, treatment of a fungal agent ...

Dermocorticoïdes : can be recommended for the treatment of vitiligo highly localized, however, strict supervision is necessary

immunosuppressive local (in France, Tacrolimus ointment, at 0.03% and 0.1%) : are used for the treatment of vitiligo often combined with phototherapy

Cryothérapie : formed or surface dermabrasion, can induce repigmentation lenticular hypochromia of Hypomelanosis Idiopathic drops

Treatment surgical : several trials of these treatment methods mélanocytopéniques hypomélanoses,  including vitiligo,  have been tempted :  transplant autologous melanocytes skin depigmented

antioxidants : in the context of the hypothesis that considers vitiligo results from a deficiency of free radical neutralization systems in the skin

Photo-chemotherapy oral : combining psoralen and UVA, currently remains the only treatment that offers hope to get,  rarely,  repigmentation of lesional skin of vitiligo