Chapter 054. Skin Manifestations of Internal Disease (Part 9)

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Absence of melanocytes. b Normal number of melanocytes. c Platelet storage defect and restrictive lung disease secondary to deposits of ceroid-like material; one form due to mutations in β subunit of adaptor protein. d Giant lysosomal granules and recurrent infections. The differential diagnosis of localized hypomelanosis includes the following primary cutaneous disorders: idiopathic guttate hypomelanosis, postinflammatory hypopigmentation, tinea (pityriasis) versicolor, vitiligo, chemical leukoderma, nevus depigmentosus (see below), and piebaldism (Table 54-9). In this group of diseases, the areas of involvement are macules or patches with a decrease or absence of pigmentation. ...

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Nội dung Text: Chapter 054. Skin Manifestations of Internal Disease (Part 9)

Chapter 054. Skin Manifestations of Internal Disease (Part 9) a Absence of melanocytes. b Normal number of melanocytes. c Platelet storage defect and restrictive lung disease secondary to deposits of ceroid-like material; one form due to mutations in β subunit of adaptor protein. d Giant lysosomal granules and recurrent infections. The differential diagnosis of localized hypomelanosis includes the following primary cutaneous disorders: idiopathic guttate hypomelanosis, postinflammatory hypopigmentation, tinea (pityriasis) versicolor, vitiligo, chemical leukoderma, nevus depigmentosus (see below), and piebaldism (Table 54-9). In this group of diseases, the areas of involvement are macules or patches
with a decrease or absence of pigmentation. Patients with vitiligo also have an increased incidence of several autoimmune disorders, including hypothyroidism, Graves' disease, pernicious anemia, Addison's disease, uveitis, alopecia areata, chronic mucocutaneous candidiasis, and the polyglandular autoimmune syndromes (types I and II). Diseases of the thyroid gland are the most frequently associated disorders, occurring in up to 30% of patients with vitiligo. Circulating autoantibodies are often found, and the most common ones are antithyroglobulin, antimicrosomal, and antithyroid-stimulating hormone receptor antibodies. There are four systemic diseases that should be considered in a patient with skin findings suggestive of vitiligo—Vogt-Koyanagi-Harada syndrome, scleroderma, onchocerciasis, and melanoma-associated leukoderma. A history of aseptic meningitis, nontraumatic uveitis, tinnitus, hearing loss, and/or dysacusis points to the diagnosis of the Vogt-Koyanagi-Harada syndrome. In these patients, the face and scalp are the most common locations of pigment loss. The vitiligo- like leukoderma seen in patients with scleroderma has a clinical resemblance to idiopathic vitiligo that has begun to repigment as a result of treatment; that is, perifollicular macules of normal pigmentation are seen within areas of depigmentation. The basis of this leukoderma is unknown; there is no evidence of inflammation in areas of involvement, but it can resolve if the underlying connective tissue disease becomes inactive. In contrast to idiopathic vitiligo, melanoma-associated leukoderma often begins on the trunk, and its appearance
should prompt a search for metastatic disease. It is also seen in patients undergoing immunotherapy for melanoma, with cytotoxic T lymphocytes presumably recognizing cell surface antigens common to melanoma cells and melanocytes. There are two systemic disorders (neurocristopathies) that may have the cutaneous findings of piebaldism (Table 54-10). They are Shah-Waardenburg syndrome and Waardenburg syndrome. A possible explanation for both disorders is an abnormal embryonic migration or survival of two neural crest–derived elements, one of them being melanocytes and the other myenteric ganglion cells (leading to Hirschsprung disease in Shah-Waardenburg syndrome) or auditory nerve cells (Waardenburg syndrome). The latter syndrome is characterized by congenital sensorineural hearing loss, dystopia canthorum (lateral displacement of the inner canthi but normal interpupillary distance), heterochromic irises, and a broad nasal root, in addition to the piebaldism. Patients with Waardenburg syndrome have been shown to have mutations in three genes including two (PAX- 3 and MITF) that encode DNA-binding proteins, while patients with Hirschsprung disease plus white spotting have mutations in one of three genes—endothelin 3, endothelin B receptor, and SOX-10. Table 54-10 Hypopigmentation (Primary Cutaneous Disorders, Localized)
Clinic Woo Skin Patho Tre al d's Lamp Biopsy genesis atment Characterist Examinatio Specimen ics n (UV-A; Peak = 365 nm) Idiopath Com Less Abrupt Possi Non ic guttate mon; enhancemen decrease in ble somatic e hypomelanosis acquired; 1– t than epidermal mutations as 4 mm in vitiligo melanin a reflection diameter content of aging; UV Shins exposure and extensor forearms Postinfla Can Depe Type Block Trea mmatory develop nds on of in transfer of t hypopigmentati within active particular inflammatory melanin underlying on lesions, as in disease infiltrate from inflammato
subacute Usual depends on melanocytes ry disease lupus, or ly less specific to after the enhancemen disease keratinocyte lesion fades, t than in s could be as in vitiligo secondary to dermatitis edema or decrease in contact time Destr uction of melanocytes if inflammator y cells attack basal layer Tinea Com Golde Hypha Invasi Sele (pityriasis) mon disorder n e and budding on of nium versicolor fluorescence yeast in stratum sulfide Upper stratum corneum by 2.5%; trunk and the yeast topical
neck corneum Malassezia imidazoles; oral Shawl Yeast imidazoles -like is lipophilic or triazoles distribution and produces C9 Youn and C11 g adults dicarboxylic Macul acids, which es have fine in vitro white scale inhibit when tyrosinase scratched Vitiligo Acqui More Absen Possi Topi red; apparent ce of ble cal progressive melanocytes autoimmune glucocortic Chalk phenomenon oids; Symm -white Mild that results topical etric areas of inflammation in calcineurin complete destruction inhibitors; pigment loss of UV-B;
Perior melanocytes PUVA; ificial— —cellular transplants; around and/or depigmenta mouth, nose, humoral tion if eyes, nipples, widespread Alter umbilicus, native anus hypothesis is Other self- areas—flexor destruction wrists, of extensor melanocytes distal and extremities circulating antibodies or Segm cytotoxic T ental form is cells as a less secondary common— phenomenon unilateral, dermatomal- like
Chemica Simila More Decrea Expos Avo l leukoderma r appearance apparent sed number ure to id exposure to vitiligo or absence of chemicals to Chalk melanocytes that offending Often -white selectively agent, then begins on destroy treat as hands melanocytes, vitiligo Satelli in particular te lesions in phenols and areas not catechols exposed to (germicides; chemicals adhesives) Relea se of cellular antigens and activation of circulating lymphocytes may explain satellite
phenomenon Piebaldi Autos Enha Hypo Defec Non sm omal ncement of melanotic t in e; dominant leukoderma areas—few to migration of occasionall and no melanoblasts y Conge hyperpigme melanocytes from neural transplants nital, stable nted crest to White macules ventral skin forelock or failure of melanoblasts Areas to survive or of differentiate hypomelanos in these is contain areas normally pigmented Mutat and ions within hyperpigmen the c-kit ted macules proto- of various oncogene that encodes
sizes the tyrosine kinase Symm receptor for etric stem cell involvement growth of central factor forehead, ventral trunk, and mid regions of upper and lower extremities Note: PUVA, psoralens +ultraviolet A irradiation; UV-B, ultraviolet B.