Ichthyosis

INTRODUCTION Ichthyosis represents a heterogeneous group of disorders of skin keratinization. Four major classes of ichthyosis are recognized. The most common type is ichthyosis vulgaris, an autosomal dominant disease with onset prior to age five years. Fine, light scales with flexural sparing is present. The eyelids and eyelashes are often involved. In X-linked ichthyosis affected males manifest large, dark scales with flexural involvement during the first year of life due to a deficiency of microsomal enzyme cholesterol sulfatase. Lamellar ichthyosis is an autosomal recessive condition present at birth. The infant is invested in a thick collodion membrane that is usually shed in 10 to 12 days. Large, thick uniform scales with generalized involvement is characteristic. Epidermolytic hyperkeratosis, a rare autosomal dominant disorder, presents at birth with red, moist skin and blisters. Thick scales form within several days. Facial involvement is usually mild. Associated corneal changes include gray stromal opacities, punctate epithelial erosions, gray elevated nodules, and band keratopathy.

CLINICAL PRESENTATION In lamellar ichthyosis the skin shows, course, yellow scales with raised corners which range is size from fine to large and plate-like. These scales are arranged in a mosaic pattern resembling fish skin and are easily shed. Fine, light to dark thick scales are present on the eyelid skin and at the base of the eyelashes. Alopecia of the scalp and loss of eyelashes is common. Often there is keratinization of the lid margin and palpebral conjunctiva, accompanied by a papillary reaction. With time the skin tightens resulting in ectropion which may be very severe. Corneal exposure with secondary scarring and vascularization is a constant threat.

Epidermolytic Hyperkeratosis

HISTOPATHOLOGY A moderate degree of hyperkeratosis and a thin or absent granular cell layer are the usual findings in ichthyosis vulgaris. Keratotic follicular plugs may result from extension of hyper-keratosis into hair follicles.

Baby Refsum Disease

DIFFERENTIAL DIAGNOSIS Few other disorders give the clinical picture of ichthyosis. Most notably the differential includes psoriasis, exfoliative dermatitis, collodion baby syndrome, harlequin fetus, Refsum's disease, Sjogren-Larsson syndrome, Conradi's disease, KID syndrome, and Trichothiodystrophy.

TREATMENT When seen in newborn infants care in a neonatal intensive care unit is essential for placement in a high humidity incubator and general hydration, and to monitor for infection. Systemic steroids may be lifesaving in the bullous forms of infantile ichthyosis. In adults steroids and antimetabolites have not been of value. Topical hydration techniques, keratolytic agents, and retinoids are applied to help soften the scales. Newer therapies include alpha hydroxyl acids to reduce itching and treat mild eczemas, topical retinoids to inhibit microcomodo formation and to reduce cohesiveness of follicular epithelial cells, and topical tazarotene (Tazorac) 0.05% gel which is a retinoid prodrug that moduolates epithelial tissue differentiation and proliferation and may also have anti-inflammatory and immunomodulatory properties. Ectropion repair will usually require skin grafts, but it may be difficult to find an adequate donor site. However, the grafts tend to scale and contract often making any surgical gains short-lived. Foreskin may not be involved and may make an acceptable donor site.

REFERENCES

Cruz AA, Menezes FA, Chaves R, et al. Eyelid abnormalities in lamellar ichthyosis. Ophthalmology 2000; 107:1895-1898.

Hosal BM, Abbasogglu OE, Gursel E. Surgical treatment of cicatricial ectropion in lamellar Ichthyosis. Orbit 1999; 19:37-40.

Jay B, Blach R, Wells RS. Ocular manifestations of ichthyosis. Br J Ophthalmol 1968; 52:217-226.

Messmer EM, Kenyon KR, Rittinger O, Janecke AR, Kampik A. Ocular manifestations of keratitis-ichthyosis-deafness (KID)

syndrome. Ophthalmology 2005; 112:1-6. Peled I, Bar-Lev A, Wexler MR. Surgical correction of ectropion in lamellar Ichthyosis. Ann Plast Surg 1982; 8:429-431.

Rose HM. Lid changes in non-bullous ichthyosiform erythemoderma. Br J Ophthalmol 1971; 55:750-752. Sever R, Frost P, Weinstein G. Eye findings in ichthyosis. JAMA 1968; 206:2283-2286. Singh AJ, Atkinson PL. Ocular manifestations of congenital Ichthyosis. Eur J Ophthalmol 2005; 15:118-122. Uthoff D, Gorney M, Teichmann C. Cicatricial ectropion in ichthyosis: a novel approach to treatment. Ophthal Plast Reconstr Surg 1994; 10:92-95.

How To Deal With Rosacea and Eczema

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