Inflammatory skin disorders
Inflammatory skin disorders are a significant part of dermatopathology. They lead to trepidation among pathologists that don't see lots of skin.
Spongiotic dermatitides
DDx:[1]
- Atopic dermatitis.
- Contact dermatitis.
- Stasis dermatitis.
- Seborrheic dermatitis.
- Nummular dermatitis.
- Spongiotic drug eruption.
Psoriasiform dermatitides
Regular psoriasiform dermatitis
DDx:[1]
- Psoriasis vulgaris.
- Dermatophyte infection.
- Pityriasis rubra pilaris.
Irregular psoriasiform dermatitis
Interface dermatitides
Vacuolar interface dermatitides
DDx:[1]
- Erythema multiforme.
- Lichen sclerosus.
- Fixed drug eruption.
Others:[1]
- Graft versus host disease.
- Dermatomyositis.
- Systemic lupus erythematosus.
- Morbillifrom viral exanthem.
Lichenoid interface dermatitides
DDx:[1]
- Lichen planus
- Mycosis fungoides.
- Discoid lupus erythematosus.
- Lichenoid drug eruption.
- Fixed drug eruption.
Bullous disease
Subcorneal bullous disorders
DDx with acantholysis:[1]
DDx without acantholysis:DDx:[1]
- Subcorneal pustular demratosis (Sneddon-Wilkinson disease)
- Pustular psoriasis.
- Pustular drug eruption (acute generalized exanthematous pustulosis).
Suprabasilar bullous disorders
DDx:[1]
- Pemphigus vulgaris.
- Hailey-Hailey disease (benign familial pemphigus).
- Darier disease.
- Grover disease (transient acantholytic dermatosis).
Subepidermal bullous disorders
DDx:[1]
- Bullous pemphigoid.
- Cicatricial pemphigoid.
- Porphyria cutanea tarda.
- Epidermolysis bullosa acquista.
- Dermatitis herpetiformsis.
- Linear IgA disease.
Others:
- Insect bite.
- Coma blister.
- Bullous systemic lupus erythematosus.
Perivascular inflammation
Lymphocytes
Lymphocytes (tightly cuffed):[1]
- Infections.
- Medications.
- Malignancy.
- Vitiligo (with absent melanocytes).
- Scleroderma/morphea.
Lymphocytes & plasma cells +/-eosinophils:
- Erythema chronicum migrans (Lyme disease).
Lymphocytes (not tightly cuffed):
- Viral exanthems.
- Drug eruptions.
Lymphocytes & eosinophils:
- Drug reaction.
- Insect bite.
- Dermatophyte infection.
Neutrophils
DDx:[1]
- Cellulitis.
- Neutrophilic eccrine hidradenitis (idiopathic palmar-plantar hidradenitis)
With eosinophils:
- Urticaria.
Eosinophils
DDx:[1]
- Hypersensitivity reaction/drug reaction.
- Insect bite.
- Bullous pemphigoid, urticarial.
Mast cells
Vasculitis
Main article: Vasculitides