Acrodermatitis enteropathica

Acrodermatitis enteropathica is a rare genetic condition where there is malabsorption of zinc through the intestinal cells. It is characterised by well-demarcated erythema and crusting around the mouth and/or anus, alopecia, and diarrhoea.

This chapter is set out as follows: 

• Acrodermatitis enteropathica is very rare affecting approximately 1:500,000 individuals 
• It is associated with mutations in the gene SLC39A4, which codes the zinc intestinal transporter protein ZIP4
• The inheritance is autosomal recessive (ie one defective gene must be inherited from each parent)

• Males and females are equally affected
• Symptoms usually occur in bottle-fed infants within a few days or weeks after birth and breast-fed infants soon after weaning
• Zinc deficiency may rarely arise in adults as a consequence of dietary deficiency, intestinal malabsorption, after traumatic events such as burns or surgery, the Nephritic syndrome, and the Glucagonoma syndrome

Distribution

• ​Predominantly around body openings such as the mouth, anus, and eyes
• The skin on the elbows, knees, hands, and feet may also be involved

Morphology

• Well-demarcated erythema 
• Erythema progresses to vesicles, bullae, pustules, desquamation and crusting 

Other cutaneous features

• Alopecia 
• Secondary infection is common
• Impaired wound healing
• Paronychia 
• A red glossy tongue and mouth ulcers

Non-cutaneous features

• ​Apathy and irritability
• Diarrhoea and failure to thrive
• Frequently blepharitis, conjunctivitis and photophobia

• Serum zinc concentration is usually low but can be normal 

• Patients respond to oral zinc sulphate within a few days. The normal dose is 150–400 mg/day in childhood; a lower dose may suffice after puberty but 400–500 mg/day is needed during pregnancy. Treatment is life long 
• If zinc sulphate causes gastric problems other zinc preparations have been recommended but they are not widely available