Netherton syndrome is a genetic condition affecting about five people per million. It appears at or soon after birth with skin rash, unusual hair, allergy and abnormal immunity. Affected babies may become very ill, but severity varies and most dermatologists see only a few cases. Doctors from a specialist referral centre in Paris reviewed cases seen over 38 years to try to put together some guidelines.

Of 43 babies with Netherton syndrome, half suffered dehydration with high sodium levels in their blood. Two-thirds were underweight, a quarter had cow’s milk allergy and a quarter had diarrhoea. Infections were common: two-thirds had skin infections, others had lung, catheter, kidney or heart infections and 42% developed septicaemia (blood infection). Some unusual hormone problems occurred. Four babies died in the first 9 months, usually with infection but three also had very high sodium levels.

The typical rash and hair changes may not be apparent early on. A suspected diagnosis of Netherton syndrome may be confirmed by absence of a key component called LEKTI in a skin biopsy (where a small section of the skin is removed for testing) and by changes (mutations) in the SPINK5 gene in blood. Babies with one particular mutation were more severely affected.

Because of the risk of serious infection, careful hygiene measures are advised especially during the first months of life. Excessive protein and fluid are lost through damaged skin and bowel so babies with Netherton syndrome need almost double quantities of fluid and increased amounts of protein and calories. The authors call for expert multidisciplinary care in specialist units.

Linked Article: Bellon et al. Br J Dermatol 2021; 184:532–537.