Clinical Features of Lamellar Ichthyosis
Lamellar ichthyosis presents with large, dark brown, polygonal, plate-like scales covering the entire body surface with minimal to no erythema, typically beginning at birth as a collodion membrane that subsequently evolves into the characteristic scaling pattern. 1, 2
Neonatal Presentation
- Collodion membrane at birth: Affected neonates are typically born encased in a tight, shiny, translucent membrane that subsequently sheds within the first weeks of life 3
- Erythroderma and peeling: The initial presentation includes generalized erythroderma with subsequent desquamation as the collodion membrane resolves 4
Cutaneous Features
Primary Skin Manifestations
- Large, polygonal, plate-like scales: The hallmark feature consists of large, dark brown to grayish-brown, tightly adherent scales arranged in a plate-like pattern across the entire body surface 1, 2
- Generalized distribution: Scaling affects the entire body surface, including trunk, extremities, and often palms and soles 5, 1
- Minimal erythema: Unlike other forms of congenital ichthyosis, lamellar ichthyosis typically presents with minimal to no underlying erythema 2
- Hyperkeratosis: Marked thickening of the stratum corneum with excessive keratin accumulation 5
- Fissuring: Deep cracks and fissures may develop, particularly in areas of flexion or mechanical stress 6
Facial and Ocular Complications
Eyelid Abnormalities
- Ectropion: Eversion of the eyelids (both upper and lower) is a characteristic feature that can be severe and bilateral 4, 7, 3
- Lagophthalmos: Incomplete eyelid closure occurs even during blinking when ectropion is present, leading to chronic corneal exposure 4
- Eclabium: Eversion of the lips is commonly associated with the facial presentation 7, 3
Ophthalmic Complications
- Corneal exposure: The inability to fully close eyelids leads to chronic exposure of the ocular surface 4, 7
- Dry eye syndrome: Lagophthalmos and ectropion predispose to severe ocular surface desiccation requiring frequent lubrication 4
- Risk of corneal ulceration: Untreated corneal exposure can progress to ulceration and potentially corneal perforation leading to phthisis bulbi 7
- Keratinization of palpebral conjunctiva: Chronic exposure may lead to conjunctival keratinization if left untreated 4
Ear Complications
- Ear canal blockage: Accumulation of excessive keratin and scales within the external auditory canal is common and may require periodic mechanical removal 4
- Frequency of intervention: Microsuctioning, debridement, or curettage by ENT specialists is typically needed one to four times yearly 4
Associated Features
- Absence of hair abnormalities: Unlike some other ichthyoses, lamellar ichthyosis typically does not involve primary hair shaft abnormalities, though secondary hair loss may occur 1
- Absence of neurological abnormalities: Isolated lamellar ichthyosis is not associated with neurological deficits 1
- Nail involvement: Subungual hyperkeratosis may be present with thickening beneath the nail plate 6
- Pruritus: Itching is a common symptom that significantly impacts quality of life 6
Genetic and Histopathologic Features
- Autosomal recessive inheritance: The condition follows an autosomal recessive pattern, with TGM1 gene mutations found in approximately 50% of cases 3, 2
- Histopathology: Skin biopsy reveals marked hyperkeratosis with lamellae formation 1
- Incidence: Lamellar ichthyosis occurs in approximately 1 per 100,000 to 300,000 live births 1, 6
Critical Clinical Pitfalls
Early recognition of ectropion is essential: Medical management with lubricants, emollients, and eyelid massage can prevent progression to cicatricial ectropion, which would require surgical intervention 7. If ectropion is managed early with oral acitretin, skin emollients, lubricating eye drops, and daily eyelid massage, excellent results can be achieved within 6 months, avoiding the need for eyelid skin grafting 7.