| Pathogenesis |
Sporadic HHV-6/7 systemic reactivation |
Reaction to a drug/vaccine |
| Morphology of the lesions |
Finely scaling erythematous macules and/or plaques |
Dusky-red macules and/or plaques with possible desquamation |
| Distribution |
Involvement of the trunk and limbs (face spared): lesions symmetrically oriented with their long axes along the cleavage lines (theater curtain distribution) |
Diffuse and confluent lesions on trunk, limbs and face |
| Oral mucosa involvement |
Possible (16% of cases) |
Possible (50% of cases) |
| Herald patch |
Present (12%-90% of cases) |
Absent |
| Itch |
Absent or mild |
Intense |
| Prodromal symptoms |
Present (>69% of cases) |
Absent |
| Laboratory exams |
Within normal ranges |
Possible peripheral eosinophilia (42% of cases) |
| Virologic investigations |
Signs of HHV-6 and/or HHV-7 systemic reactivation: detection of HHV 6/7 DNA in plasma and peripheral blood mononuclear cells; detection of positive IgM antibodies against HHV-6/7 in serum. |
No signs of HHV-6 and HHV-7 systemic reactivation |
| Histopathology |
Parakeratosis, spongiosis (epidermis); extravasated red blood cells, lymphocyte infiltrate (dermis) |
Interface dermatitis and eosinophils |
| Therapeutic options |
Bed rest |
Drug withdrawal |
| Mean duration |
45 day |
14 days after discontinuing the drug |
