Eczema coxsackium (also known as atypical hand, foot and mouth) is a variant of hand, foot, + mouth in children with eczema (atopic dermatitis). It can also occur in children with broken skin not due to eczema such as sunburn, napkin dermatitis, wounds and scars.
It is due to coxsackievirus, a form of enterovirus, typically coxsackievirus A6 and A16. Children may develop a vesiculobullous eruption with or without ulceration in areas of active or inactive eczema.
Like classical hand, foot and mouth, eczema coxsackium typically affects preschool children with lesions on hands, feet, buttocks, torso and face, but mostly localising to sites of broken skin. Fever and mouth ulcers are common.
The course is similar to classical hand, foot and mouth disease. Children can become dehydrated if not drinking and may require admission for hydration. Treat active eczema with emollients but avoid topical steroids while the child is febrile.
References
https://dontforgetthebubbles.com/common-rashes-module/
https://www.gponline.com/skin-conditions-young-children/dermatology/dermatology/article/1412380