C i.e. Nevus achromicus Hypopigmented Patch Unilateral Nevus achromicus (depigmentosus) - Mostly presents with unilateral, stable single, well circumscribed oval or rectangular localized area of hypomelanosis (depigmented skin) with feathered margins. - It is congenital (i.e. present at bih)Q but sometimes may not be apparent at bih. - It remains stable in size and color over time and typically has no associated findings Q. - Lesions occur most commonly on trunk. Hairs within the lesiosn are usually depigmented. Histology shows normal or reduced number of melanocytes. 3 variants of lesion are single (mc), segmental and systematized (very rare). - Erythema appears on massage - Pressure with glass slide does not make the lesion disappear. Nevus anaemicus - Developmental, solitary (unilateral) white (pale) round flat patch, usually on trunk and present at bih. It is stable (i.e. does not increase in size). Thought to have vascular filling defect. - Massage fails to develop erythema in lesionQ. Pressure with glass slide makes the lesion disappear & indistinct from surrounding skin. Hypomelanosis of Ito (Linear nevoid hypopigmentation/ Pigmentary Mosacism/ Incontinentia pigmenti achromians of Ito) - This neurocutaneous disorder results from migration of 2 clones of melanocytes, each with a different pigment potential. - It may present with widespread bilateral (symmetrical) or unilateral areas of hypopigmentation in form of whorls (swirls) and streaks occurring along Blaschko's lines. - One third cases are associated with abnormalities involving musculoskeletal system (asymmetry), CNS (convulsions & mental retardation), teeth, and eyes (hypeelorism & strabismus). Bilateral Piebaldism - It is AD condition characterized by congenital stable areas of vitiligo like amelanotic skin with white forelock. - Amelanotic patches of skin totally devoid of pigment are present at bih (congenital) and remain unchanged throughout life (stable)Q. - Frontal median or paramedian patch with a mesh of white hair (white foelock) is most common lesion; rest of scalp hair are pigmented. - Often, white patches occur bilaterally mostly but not necessarily (always) symmetrically on ventral trunk (chest & abdomen) and limbs (upper & lower extremities). Occasionally they are found on face esp. chin - Back as well as hands and feet (acral area) remain normally pigmented (acral sparing). - Islands of normal or hypermelanotic skin occur in white depigmented areasQ. - Piebaldism can be distinguished from vitiligo (where the lesions are acquired later in life) by almost invariable presence of white forelock and islands of normal pigmented skin in hypomelanotic areasQ as well as configuration & distribution of lesions. - Piebaldism may be associated with 2 systemic neurocristopathies d/t abnormal embryonic migration or survival of 2 neural crest derived elements, one being melanocytes and other myenteric ganglion cells (IA Hirschprung disease in Shah-Waardenburg syndrome) or auditory nerve cells (1/t sensorineural deafness in Waardenburg's syndrome). Waardenburg's syndrome is characterized by dystopia canthorum (lateral displacement of inner canthi but normal interpupillary distance), hetero chromic irises, broad nasal root, sensorineural hearing loss and piebaldism. Vitiligo - Usually not present at bih, oftenly stas in childhood (before 20 years age) - Hypomelanotic (milky white) macule with scalloped hyper pigmented border usually first noted at sun exposed area of face & dorsa of hands. - Affect paicularly areas that are hyper pigmented (i.e., face, axilla, groin, areola & genitalia) or subjected to repeated trauma (i.e., dora of hand, feet, elbow, knee & ankles). - Usually symmetrical but may be segmental (i.e. U/L dermatomal involving trigeminal distribution) or generalized (complete). - Increase in size, older lesions show amelanotic hair (leucotrichia)Q and damage to normal skin results in depigmentation i.e., Koebner /isomorphic phenomenon - May be associated with diabetes mellitusQ, pernicious anemia, mysthenia gravis, alopecia areata, Addison's ds, thyroid ds, hypoparathyroidism, morphea, lichen sclerosus, halo nevus & malignant melanoma - Eyes are not involved - Show paial / near complete response to treatment Albinism (Oculo-cutaneous) - Present at bih (autosomal recessive) - Diffuse hypopigmentation of skin, & hair throughout the bodyQ. - Absence of pigment in iris & retina (eye) with visual defects in form of nystagmus, poot eye sight, photophobia, transulent iridis & red reflex. - Frecklies, non- pigmented melanocytic nevi, & amelanotic melanomas may develop on sun exposed area - No response to treatment