Monday, November 10, 2014

ICHTHYOSIS

ICHTHYOSIS

by--DrSudeepKC

● Condition characterized by abnormal keratinization

● Clinical features range from mild involvement, often passed off as dry skin (xerosis) to severe widespread scaly lesions (Fig.), causing discomfort and social embarrassment.
This was an incidental postmortemfi nding. Ichthyosis can be very disfi guring and a considerable socialdisadvantage.


● Specifi c investigations are dictated by clinical presentation  -malignancy workup, HIV, and skin biopsy to rule out sarcoidosis are indicated in acquired ichthyosis.

Investigations for hereditary ichthyosis include mutational analysis, steroid sulfatase activity, (fatty alcohol [nicotinamide adenine dinucleotide [NAD] oxidoreductase activity])

● Treatment consists of hydration (humidifi cation of environment, bathing, soaking) and use of creams, lotions, or ointments for lubrication. Second-line therapies involve the use of keratolytics (urea, lactic acid, salicylic acid), topical retinoids (tretinoin, tazarotene), or calcipotriol.


CLASSIFICATION
(1) Ichthyosis vulgaris
This is a relatively common disorder (incidence 1 in 250 to 1000 births), with an autosomal mode of inheritance. It affects both genders equally and presents as dryness (xerosis) and slight to moderate fi ne, white, fi shlike scaling, particularly involving the arms and legs and characteristically sparing the
fl exures fig.
Abdominal involvement is most noticeable in thispatient. Sparing of the fl exures is characteristic of thiriant ofichthyosis.


(2) Sex-linked ichthyosis Also known as ichthyosis nigricans, this is an X-linked recessively
inherited disorder with an incidence of 1 in 6000 male births (Fig. ). It is associated with a defi ciency of the microsomal enzyme steroid sulfatase.


(3) Acquired ichthyosis This is an important paraneoplastic manifestation (Fig.  of a number of malignancies, most commonly Hodgkin’s lymphoma. It may also accompany HIV infection, sarcoidosis, and connective tissue diseases.

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