Common, typically vesicular rather than bullous:
- Varicella – tends not to affect mouth or palms/soles cf below, but more toxic
- Coxsackie – Enteroviruses such as coxsackie nearly always involve buccal mucosa and tongue (eg Hand-Foot-Mouth). If nowhere else, Herpangina tends to be posterior mouth ie tonsils, soft palate.
- HSV stomatitis tend to be more unwell, higher fever, gingivitis, cervical adenopathy, no cutaneous lesions.
- Gianotti-Crosti syndrome
- eczema herpeticum ie HSV superinfection of eczema;
- mycoplasma (but mycoplasma has been associated with every kind of rash!)
- disseminated zoster (starts in a dermatome, immunosuppressed);
- disseminated HSV;
For more dramatic blistering:
- Bullous impetigo
- Stevens Johnson syndrome esp with plaques, conjunctivitis, lesions at mucocutaneous junctions
- Urticaria (rarely)
- Dermatitis herpetiformis
- Pemphigoid (v rare in children)
- Acrodermatitis enteropathica – genetic (recessive) disorder leading to Zn deficiency. Blistering rash esp peripheries, face and nappy; diarrhoea (Normal Zn is 10-23).