# Acrodermatitis Enteropathica

> Acrodermatitis enteropathica for NEET-PG Dermatology covers SLC39A4 zinc deficiency, the triad of dermatitis, alopecia and diarrhoea, and zinc treatment.

- Canonical URL: https://prepelephant.com/topics/neet-pg/dermatology/acrodermatitis-enteropathica
- Exam / course: NEET-PG · Subject: Dermatology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Fitzpatrick's Dermatology; Nelson Textbook of Pediatrics
- How to cite: "Acrodermatitis Enteropathica", PrepElephant, https://prepelephant.com/topics/neet-pg/dermatology/acrodermatitis-enteropathica

## Direct answer

Acrodermatitis enteropathica is an autosomal recessive disorder of zinc absorption caused by mutations in the SLC39A4 gene, presenting in infancy with periorificial and acral dermatitis, alopecia and diarrhoea. The same picture arises in acquired zinc deficiency from zinc-poor weaning diets, zinc-free parenteral nutrition or malabsorption. Serum zinc is low, and a dramatic response to oral zinc supports the diagnosis.

## What you must remember

- **Gene:** SLC39A4, which encodes the intestinal zinc transporter ZIP4.
- **Classic triad:** periorificial and acral dermatitis, alopecia and diarrhoea, often with growth failure, recurrent infections and irritability.
- **Distribution:** the eyes, mouth, nose, anus and genitalia, plus the hands and feet, with vesicles and pustules at the margins.
- **Onset:** usually soon after weaning from breast milk, whose zinc is better absorbed, so the transporter defect then becomes clinically evident.
- **Acquired causes:** malnutrition, malabsorption, zinc-free total parenteral nutrition, chronic liver disease and alcohol-related disease.
- **Laboratory clues:** low serum zinc, with low alkaline phosphatase, because zinc is a cofactor for the enzyme.
- **Treatment:** oral zinc sulphate or gluconate, with lifelong supplementation for the inherited form and correction of the cause for the acquired form.
- **Mimics:** candidiasis, biotin deficiency and necrolytic migratory erythema of glucagonoma.

## Inherited and acquired zinc deficiency side by side

Both forms produce the same skin, so the history and the family pattern separate them. The table sets out the main differences.

| Feature | Inherited (AE) | Acquired |
|---|---|---|
| Cause | SLC39A4 mutation | Diet, malabsorption, parenteral feeding |
| Onset | Usually at weaning | Any age |
| Family history | Often positive | Absent |
| Long-term plan | Lifelong zinc | Treat the cause and replete zinc |

Both forms respond to zinc, which is why a dramatic response is supportive but not a substitute for finding the cause. An infant with a classic rash soon after weaning and a family history points to the inherited form, while a child on prolonged feeds without zinc points to the acquired one.

Response time is the practical bedside clue. Dermatitis and diarrhoea usually improve within days to a few weeks of oral zinc, so a patient who fails to respond should prompt a search for malabsorption, ongoing losses or an alternative diagnosis such as biotin deficiency. Repeat zinc levels after treatment confirm that replacement has actually occurred.

## Where the exam tries to catch you

Stems test whether you can link a rash to a nutritional cause and then check the cofactor enzyme.

- **Trap:** treating periorificial dermatitis in an infant with topical steroids alone. **Correct:** the problem is systemic zinc deficiency, so measure serum zinc and start oral zinc.
- **Trap:** calling every zinc-responsive rash inherited. **Correct:** acquired deficiency from parenteral feeding or malabsorption looks identical and needs a different plan.
- **Trap:** confusing necrolytic migratory erythema with acrodermatitis enteropathica. **Correct:** glucagonoma causes a migratory rash, so check glucagon levels when zinc studies are normal.

## Frequently asked questions

### Which gene is mutated in inherited acrodermatitis enteropathica?

The SLC39A4 gene, which encodes the intestinal zinc transporter ZIP4, is mutated in inherited acrodermatitis enteropathica. The autosomal recessive defect impairs zinc uptake from the diet, so the deficiency usually appears after weaning from breast milk, whose zinc is better absorbed.

### How does acquired zinc deficiency differ from the inherited form?

Acquired zinc deficiency results from malnutrition, malabsorption, zinc-free parenteral nutrition or liver disease rather than a genetic defect. It responds once the cause is corrected, whereas the inherited form needs lifelong zinc supplementation.

### Which laboratory tests support zinc deficiency in acrodermatitis enteropathica?

Low serum zinc with low alkaline phosphatase supports the diagnosis of acrodermatitis enteropathica, because zinc is a cofactor for alkaline phosphatase. A clinical response to oral zinc then strengthens the picture.

### Which tumour mimics the rash of zinc deficiency?

Glucagonoma causes necrolytic migratory erythema, a rash that can resemble acrodermatitis enteropathica. A glucagon level is worth checking when zinc studies are normal and the rash is migratory.