Lamellar ichthyosis, also known as ichthyosis lamellaris and nonbullous congenital ichthyosis, is a rare inherited skin disorder, affecting around 1 in 600,000 people.
Presentation
Affected babies are born in a collodion membrane – a shiny, waxy-appearing outer layer on the skin. This is shed 10–14 days after birth, revealing the main symptom of the disease: extensive scaling of the skin caused by hyperkeratosis.
With increasing age, the scaling tends to become concentrated around joints in areas such as the groin, the armpits, the inside of the elbow, and the neck. The scales often tile the skin and may resemble fish scales.
Collodion baby
In medicine, the term collodion baby applies to newborns who appear to have an extra layer of skin (known as a collodion membrane) that has a collodion-like quality. It is a descriptive term, not a specific diagnosis or disorder; as such, it is a syndrome. Strategies to prevent these problems include the use of emollients or nursing the baby in a humidified incubator. There is an increased risk of skin infection and mechanical compression, leading to problems like limb ischemia.
The condition is not thought to be painful or in itself distressing to the child. Nursing usually takes place in a neonatal intensive care unit, and good intensive care seems to have improved the prognosis markedly.
In around 10% of cases the baby sheds this layer of skin and has normal skin for the rest of its life. which means the defective gene is located on an autosome, and both parents must carry one copy of the defective gene in order to have a child born with the disorder. Carriers of a recessive gene usually do not show any signs or symptoms of the disorder.
One form of ichthyosis lamellaris (LI1) is associated with a deficiency of the enzyme keratinocyte transglutaminase.
Genes involved include:
{| class="wikitable"
|-
! Type
! OMIM
! Gene
! Locus
|-
| LI1
|
| TGM1
| 14
|-
| LI2
|
| ABCA12
| 2q34
|-
| LI3
|
| CYP4F22
| 19p13.12
|-
| LI5
|
| CERS3
| 15q26.3
|}
Treatments
As with all types of ichthyosis, there is no cure but the symptoms can be relieved.
- Moisturizers
- Prevention of overheating
- Eye drops (to prevent the eyes from becoming dried out)
- Systemic retinoids (isotretinoin and acitretin are very effective, but careful monitoring for toxicity is required. Only severe cases may require intermittent therapy.)
Psychological therapy or support may be required as well.
See also
- Ichthyosis
- Congenital ichthyosiform erythroderma
- Bullous congenital ichthyosiform erythroderma