Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
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Pathology Associates Of Lexington, P.A.
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        Skin Pigmentation Disorders:
      

Since internet links change so often, to see clinical photos patients of any of the below, simply clip & paste the disorder name into "Google images" (but realize that some internet images may not be accurate & may be from non-authoritative sources). The word macular means that the spot does not have any "feel" of being raised or rough. An excellent site with disorders comprehensively categorized is HERE...but it probably is not complete for all the rare syndromes listed in some texts6.

National Skin Centre review of depigmentation with good clinical photos of some disorders HERE.

Hypopigmentation (lighter color):
name: clinical: histology: treatment:
pityriasis alba common & begins in childhood; starts as faintly scaley & then macular & has faded-bordered, small-to-large, round to oval spots; almost always diagnosed by clinical features. minimal epidermal change (lymph. exocytosis, spongiosis, parakeratosis) plus mild loss of basal keratocyte melanin; no loss melanocytes; a few melanophages; & sparse superficial perivascular lymphohistiocytic infiltrate goes away
Tinea (pityriasis) versicolor macular (can be hypo, hyper, and erythematous) & common & often coalesce & caused by the Pityrosporum ovale yeast called Malazzesia furfur in mycelial phase; "skin stretch test" to diagnose by a scale being evoked by the stretching
HERE
Treatment
progressive macular hypomelanosis (PMH) [known as 'cutis trunci variata" in Venezuala, Creole dyschromia in the French West Indies, idiopathic large macule hypomelanosis in the USA, & nummular and confluent hypomelanosis of the trunk in the Netherlands8] macular & fairly common & mostly young women; overlapping coin-sized pigment fading; somehow related to P. acnes & shows red perifollicular color under Wood's light exam (to observe the red follicular fluorescence, a completely dark room is essential, with the use of a strong Wood lamp. The fluorescent tubes need to warm up, and the observer has to adapt to the dark environment for at least 3 minutes8)[CP08-6].
gram-positive bacteria in the pilosebaceous duct, and a mild perifol,licular lymphocytic infiltrate
tends go away by middle age; topical antibiotic plus UVA treatments HERE?
hypomelanosis of Ito (incontinentia pigmenti achromians) macular & rare & appears @ birth or infancy & 3rd most common neurocutaneous disorder; tends linear & directed along Langer's dermal cleavage lines, Blaschko's skin pattern lines, or dermatomal embryonic segments directions; associated with birth defects. reduced keratocyte & melanocyte melanin & usually normal numbers melanocytes ?
nevus depigmentosus (nevus achromicus) macular & common & usually a single coin-sized to much larger-sized spot in just under 1% of births. melanocytes present ?
postinflammatory hypopigmentaion macular & common (includes such as atopic dermatitis)   ?
Depigmentation (lighter to totally white):
idiopathic guttate hypomelanosis macular & very common & mostly very small spots in older patients (an actinic phenom?)   "watch & wait" or removal as needed
hypomelanosis of Ito see above    
postinflammatory hypopigmentaion see above    
vitiligo   complete absence of melanocytes & epidermal pigment  
albinism (e. g. pityriasis alba)   normal melanocytes & melanosomes but no melanin  

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Hyperpigmentation (darkening or dark streaks & spots):
disorder name: clinical: histology: treatment:
moles/nevi & keratoses very common & often not macular   "watch & wait" or removal as needed
lentigo/lentigenes (sunspots; age spots) macular & extremely common in older adults   "watch & wait" or removal as needed
acanthosis nigricans (AN) macular & sometimes keratotic plaques remindful of psoriasis & common, especially in the obese, tending to reflect the state of insulin resistance; rarely AN reflects an underlying malignancy orthohyperkeratotic stratum corneum overlying a mammillated hyperplastic epidermis treatment of underlying "metabolic syndrome" may help
melasma (chloasma) macular & common; face, cheeks of women mostly   ?
erythrasma macular & common; armpits, under breasts; groin; red by Wood's light exam.

bacterial populated skin

treat with topical gel of 2% erythromycin.
postinflammatory hyperpigmentation macular & common & from many causes, especially from scratching skin sores & squeezing black heads & acne pimples   ?
cafe-au-lait spots macular & seen in absence of other defects; & in Albright's syndrome & neurofibromatosis. Appear during first 2 years of life as lightly pigmented spot basal keratocyte hyperpigmentation & may see giant melanosomes n/a
lichenoid reactions7:
  • lupus
  • erythema dyschromicum perstans (EDP)
    • melanoderma toxica
    • fixed drug
    • poikiloderma of Civatte
    • berloque dermatitis
    • lichenoid melanodermatitis
  • lichen sclerosis et atrophicus (LS&A)
  • Mixed Lichenoid Dermatitis (some lesions vacuolar & some cellular)
  • macular amyloidosis (amyloid not always IDed)
depends on which disorder
biopsy discerns the interface action for proprer basic etiology classification as a histopathological "interface" or "lichenoid" lesion
depends on which disorder
pellagra hyperpigmented, symmetrical dermatosis that looks "cracked" like sunbaked mud   give niacin

References:

  1. Dermatophyte tests in dermatiology, Department of Dermatology, University of Stellenbosch, South Africa.
  2. Nail & scalp fungus, scabies, & psoriasis tests in dermatiology, Department of Dermatology, University of Stellenbosch, South Africa.
  3. Dermatoscopy, plucked hiars in AA, Tzank, Nikolsky, & Wood's light tests in dermatiology, Department of Dermatology, University of Stellenbosch, South Africa.
  4. Biopsy types & patch tests in dermatology, Department of Dermatology, University of Stellenbosch, South Africa.
  5. Dr. H. F. Jordaan's page , Department of Dermatology, University of Stellenbosch, South Africa.
  6. McKee, Calonje, & Granter, Pathology of The Skin... Two volumes, 3rd Ed. 2005.
  7. a part of the Tulane Path Dept. webfile on inflammatory dermatoses...lichenoid.
  8. Westerhof W, et. al., "Propionibacterium acnes and the Pathogenesis
    of Progressive Macular Hypomelanosis " Arch Dermatol. 2004;140:210-214, FEB 2004.
(posted 13 April 2008; update 3 May 2009)

 
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