Necrolytic acral erythema

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Necrolytic acral erythema (NAE) is a skin condition that can accompany hepatitis C infection or zinc deficiency. It usually shows up as red-to-dark plaques on the tops of the feet and toes, and sometimes on other parts of the body.

Signs and symptoms
- Early: flaccid blisters, erosions, and red-to-violaceous papules at the edges of the lesions.
- Later: well-defined, thick, scaly plaques with a dark border (hyperkeratotic plaques); surrounding skin may be red and swollen.
- Common and other areas: commonly affects the dorsum of the feet and toes; can involve ankles, legs, knees, and occasionally the buttocks, genitals, hands, and elbows. Nails, palms, and soles may also be affected.
- Course: lesions can be acute or chronic and may come and go over months to years.

Causes and pathophysiology
- The exact cause is unknown and likely multifactorial.
- The condition is linked to hepatitis C infection and zinc deficiency, but other metabolic factors (such as liver dysfunction, low amino acids, low albumin, and diabetes) may play a role.

Diagnosis
- Based on appearance and a skin biopsy.
- Early stage: epidermal necrosis with blisters, spongiosis, and acanthosis.
- Well-developed stage: necrotic keratinocytes, psoriasiform hyperplasia, subcorneal pustules, papillomatosis, and parakeratosis.
- Some cases may not show the classic histology.

Treatment and prognosis
- The most effective treatment to date is oral zinc supplementation.
- Addressing any underlying hepatitis C infection and correcting zinc deficiency are important.
- Lesions may improve with treatment, but relapses can occur.

Epidemiology
- Affects males and females about equally.
- Typical age range is 19–58 years, with a mean around 44 years and a median near 50.

See also
- Necrolytic migratory erythema (related skin condition)
- List of cutaneous conditions

This summarizes what necrolytic acral erythema is, how it presents, what might cause it, how it’s diagnosed, and how it’s treated.