What is Acrodermatitis Enteropathica?
Acrodermatitis enteropathica (AE) is a rare, autosomal recessive, inherited skin disorder associated with zinc deficiency in infants. It is hypothesized that the absence of an enzyme, oligopeptidase, prevents zinc absorption. AE can present with several eye problems including conjunctivitis, blepharitis, corneal opacities, and photophobia. The prevalence of AE is estimated to be 1 to 9 in 1,000,000, with a global incidence rate of 1 in 500,000 newborns. The disease typically manifests during infancy at the time when infants are weaned from breast milk or earlier in infants that are formula-fed.
- Acrodermatitis enteropathica (AE) is an inherited, systemic disorder due to zinc deficiency.
- AE may result in many ocular and systemic complications or death if untreated.
- Lifelong zinc supplementation is a quick and effective treatment.
Understanding Acrodermatitis Enteropathica
Zinc plays a role in cellular processes and is an integral part of various metalloenzymes and transcription factors including nucleic acid and protein synthesis, wound healing, immune system function, and free-radical scavenging. Human breast milk is a major source of zinc, especially in the first 1 to 2 months of infancy. Additionally, a zinc-binding ligand in breast milk also increases the bioavailability of zinc in human breast milk which is absent in animal milk.
Infants may present with the classic triad of acrodermatitis enteropathica (AE): alopecia, diarrhea, and a periorificial and acral skin rash. If untreated, the condition can be fatal. Early diagnosis is key to preventing both ocular and systemic complications.
In the literature, there are cases of AE with ocular presentation including punctal stenosis, corneal changes, conjunctival xerosis, and moderate dry eye disease. Additional findings may include corneal scarring and loss of Bowman’s membrane, cataract formation, ciliary body atrophy, retinal degeneration, retinal pigment epithelium depigmentation, and optic atrophy.
Risk Factors for Acrodermatitis Enteropathica
Acrodermatitis enteropathica (AE) is an inherited form of zinc deficiency caused by a defect in zinc absorption. AE results from mutations in the zinc transporter gene SLC39A4 (solute carrier family 39 member A4), leading to improper intestinal zinc absorption. It is generally considered a disease of infancy and childhood, and its presentation at birth is unusual. No differences exist in prevalence between ethnicity and race.
Acrodermatitis Enteropathica Symptoms
Acrodermatitis enteropathica (AE) can present with a few symptoms including:
- Growth retardation
- Neuropsychiatric problems
- Perinatal morbidity
- Immunological abnormalities
- Eye abnormalities
Diagnosing Acrodermatitis Enteropathica
Diagnosis is made based on clinical symptoms. Testing results of plasma zinc levels helps to confirm the diagnosis. A zinc level of less than 70 microgram/L in fasting or less than 65 microgram/dL in non-fasting individuals is diagnostic.
In some cases where a diagnosis is doubtful, a histopathological examination of the affected skin may be helpful but is not diagnostic alone. The characteristic changes include psoriasiform hyperplasia with necrolysis.
Acrodermatitis Enteropathica Treatment
The management of acrodermatitis enteropathica (AE) usually involves enteral or parenteral zinc supplementation. Lifelong supplementation with 3 mg/kg/day of elemental zinc may be required. Shortly after beginning treatment, the clinical response is dramatic and occurs within a few days. The first sign of response to treatment is less irritability followed by improvement in skin lesions. Zinc levels should be continuously monitored.
In addition, genetic counseling is recommended for families with known cases of AE.