DERMIS

Dermal Pathology

Generally any Red non scaly disease will have a dermal or interface pathology. There are several classically described reaction patterns including, Superficial and Deep perivascular, Granulomatous, Lichenoid, Vasculitic and Interface plus Panniculitic (fat involved).

The mnemonic to be used is CUL DVA EVIE  (See you later at the Department of Veterans Affairs Evie (where Evie is your girlfriend)

C - Cellulitis
U - Urticaria
L - Lupus erythematosus, Lues (syphilis) Light eruption, Lichen planus

D - Drugs
V - Viral or bacterial exanthema
A - Annular erythema

E - Erythema multiforme
V - Vasculitis
I - Infiltrates of cells, substances or organisms
E - Erythema nodosum and variants

Some interface pathology diseases can involve the epidermis sufficiently to cause epidermal changes eg Erythema multiforme  and also dermal processes which perforate will cause epidermal changes eg Perforating folliculitis in renal failure, perforating deep fungal infections and TB.

So look at a slide.

Is the pathology Epidermal or Dermal or Both. If Epidermal use the Mnemonic PMs PETAL
If dermal use the mnemonic CUL DVA EVIE

If Both then use both mnemonics.
Look for any other epidermal or dermal features or clues and then work through the diseases in the mnemonics to see which might best fit the histology in front of you.

If you see Pustules in the epidermis the mnemonic is II

I - Infective  Viral, Bacterial, Fungal, Rickettsial, Protozoa
I Inflammatory eg Drugs, Pustular psoriasis, Rare ( Scabies, Necrolytic migratory erythema, Subcorneal pustular dermatosis, Erosive pustular dermatosis, Acrodermatitis enteropathica)

If you see Vesicles or Blisters the mnemonic is ICI

I - Infective Viral Bacterial Fungal
C - Contact Dermatitis
I - Inflammatory - Drugs, Porphyria, Insect bite, Genetic bullous diseases
I - Immunological - The immune bullous diseases