Table 2. Histological parameters used to quantify the skin changes. High power field (h.p.f) = 0.196 mm².

Parameter	Score 0	Score 1	Score 2	Score 3
Epidermal cell death	No apoptosis	1–5 apoptotic or necrotic bodies per 10 h.p.f.	≥6 apoptotic or necrotic bodies per 10 h.p.f.	Full thickness epidermal necrosis
Spongiosis	No spongiosis	Focal	Involving lower 1/2 of the epidermis	Involving full thickness of the epidermis
Epidermal nuclear enlargement (average size 50 nuclei)	<10 μm	10–12 μm	12–15 μm	>15 μm
Adnexal damage	Normal hair follicles	1–5 apoptotic or necrotic bodies in pilo-sebaceous unit per 10 h.p.f.	≥6 apoptotic or necrotic bodies in pilo-sebaceous unit per 10 h.p.f.	Partial loss of hair follicles
Dermal leukocytic infiltration	No leukocytic infiltration	Leukocytes covering <10% of the dermis	Leukocytes covering 10–70% of the dermis	Leukocytes covering >70% of the dermis