More than 1.3 million children under the age of five suffered from severe malnutrition this year in the six worst-hit countries in the Sahel, a biogeographic transitional zone between the south of the Sahara desert and north of Sudanian Savanah, aljazeera.com reported.
This accounts for a 50-percent increase over 2017, said the UN children's agency, UNICEF.
"Each year in the Sahel, many children suffer from severe acute malnutrition, especially during the lean season when food becomes scarce and there is an increase in malaria and diarrheal diseases," a UNICEF press release said.
Marie-Pierre Poirier, UNICEF regional director for West and Central Africa, said such children are "more vulnerable to illnesses such as malaria and waterborne diseases".
"Likewise, if they are fighting off an illness, they are at greater risk of becoming malnourished. That is why it is also essential to prevent the spread of disease, increase access to adequate sanitation, and promote optimal infant and young child feeding practices."
This year, the problem was particularly acute across Burkina Faso, Chad, Mali, Mauritania, Niger and Senegal, the UNICEF release said.
An estimated six million people did not have enough to eat across the region during the lean season, according to the UN food agency (FAO).
Pastoralist communities were among the worst hit, because poor rains meant there was not enough vegetation for grazing, said Coumba Sow, the FAO's regional coordinator for resilience.
The Sahel has only one growing season, and if it goes poorly due to climate shocks or conflict, people must survive on whatever they have until the next one.
Climate change exacerbates the problem by making rainfall more erratic, said Sow, adding that the rains were late and suffered a prolonged break, causing many farmers to lose half their seeds.
UN agencies and local governments were currently evaluating production levels for the new season, Sow said.