Rashes Flashcards
Causes of neuts in the horn
Psoriasis Seb Derm Tinea Impetigo Candida Syphylis
Poo STICS
NB You MUST always ask for a PAS if you see neuts in the horn to exclude tinea!!!!
Causes of acantholytic dyskeratosis
Grovers Dariers Hailey hailey Warty dyskeratoma Acantholytic dyskeratoma Some PRP Some epidermal naevi
Grovers - only one thats significantly spongiotic; varying degree of FOCAL Acanth & Dysk
Dariers – some acantholysis, lots of dyskeratosis, can be benign AK-like change in adjacent epi
Hailey-Hailey – lots of acantholysis, little dyskeratosis (dilapidated brick wall)
NB pemphigus vulgaris has acantholysis w/out dyskeratosis (tombstoning)
List the main invisible dermatoses
remember VITAMU CLAP Vitiligo Icthyosis vulgaris Tinea and Pit versic Argyria Morphoea Urticaria CALM Lichen (or macular) amyloidosis Anetoderma Porokeratosis esp DSAP
What are the causes of a combined lichenoid and spongiotic reaction pattern?
Lichen striatus Drug eruption Fixed drug eruption Gianotti-Crosti syndrome late stage pityriasis rosea Lichenoid contact derm Discoid eczema Eczematous GvHD
Septal panniculitis differential
ASPEN migration + infection
Alpha1 antitrypsin deficiency (usually lobular)
Scleroderma/ morphoea profunda
Polyarteritis nodosa (rarely)
Erythema nodosum (most common)
Necrobiosis lipoidica or deep GA
Migration - migratory thrombophlebitis (rarely)
Infective causes – bacteria, myco, fungi, helminths
What’s the DD for a subepidermal bulla with neutrophils?
microabscesses
Top 5; DH - often also many eos Linear IgA bullous dermatosis (eos or neuts) EBA Bullous SLE Pemphigoid - esp p200 BP or MMP Also; Bullous vasculitis Bullous sweets Bullous urticaria Erysipelas, cellulitis
What’s the DD for a subepidermal blister with eosinophils?
Top 5; Bullous pemphigoid or pemphigoid gestationis Bullous bite rcn bullous drug eruption Mucous membrane pemphigoid EBA (usuallly neuts) Also; Linear IgA (eos or neuts) DH (usually neuts) Wells syndrome
What’s the DD for subepidermal bulla with lymphocytes?
Top 5; SJS/TEN Bullous EM Paraneoplastic pemphigus Bullous LP or LPP Bullous LS Also; PMLE Bullous allergic contact dermatitis Bullous fixed drug eruption Bullous MF Bullous infection - fungal, leprosy Bullous bite rcn
What’s the DD for a cell poor subepidermal bulla?
PCT, Pseudoporphyria EB Bullous scleroderma Diabetic bullae Burn Suction injury ischaemia/necrosis amyloid
Causes of band like infiltrate in papillary dermis?
LUMP Lichenoid reaction Urticaria pigmentosa Mycosis fungoides Pigmented purpuric dermatosis esp lichen aureus or Gojerot and Blum
What are the causes of a superficial and deep perivascular lymphocytic infiltrate?
8 Ls and DRUGS Lupus (and other autoimmune inflammatory) Lues (syphilis) Lymphocytic (infiltrates; lymphoma, pseudolymphoma etc) Lipoidica (NLD, GA) Leprosy Lepidoptra (insect bite, scabies) Light (photodermatoses) Lichen - striatus or pit lichenodis Drug eruption Dermatophyte Reticular erythematous mucinosis Urticaria Gyrate erythemas Scleroderma
What are the histological features of PLEVA and PLC?
PLEVA 8
P = parakeratosis; focal in PLC variable in PLEVA
L = lichenoid-interface type; PLC>PLEVA
E = extravasation of erythrocytes-mild; PLC
V = vasculitis (lymphocytic); PLEVA>PLC
A = apoptotic keratinocytes high in epidermis; PLEVA>PLC
“eight” (mostly CD8 T cells)
Which conditions show epidermolytic hyperkeratosis?
BE Happy Carjal Von Hysterical Bullous icthyosiform erythroderma (AKA epidermolytic hyperkeratosis) Epidermolytic verrucous epidermal naevus Hereditary painful callosities Carvajals syndrome Vorner’s palmoplantar keratoderma Icthyosis hystrix
Also;
Lesions – solitary epidermolytic acanthoma, DF, in walls of cysts and in some inflammatory, actinic or melanocytic lesions
In normal oral mucosa
What are types of micro abscesses?
In what conditions are they seen?
Munros micro abscesses = neutrophils in SC
- typical of psoriasis
- can be in Netherton’s
Spongiform pustule of Kojog = neuts in epi
- psoriasis
Pautrier micro abscesses = atypical lymphocytes in epi
- MF
PseudoPautrier micro abscesses = langerhans cells
- contact dermatitis (esp allergic)
- drug eruption
- pityriasiform spong pattern
- Langerhans cell histiocytosis
What are the key features in herpes infections?
Viral cytopathic changes; 3 Ms =
moulding
margination of chromatin
multinucleated keratinocytes
Also;
Epidermal necrosis and balloon degeneration
Large, pale, steel grey keratinocyte nuclei
pink keratohyalin intranuclear inclusions (Lipschutz bodies)
IHC can distinguish HSV1/HSV2/ZVZ
What are Pan lymphoma, Pan T-cell and pan B-cell markers?
Pan lymphoma = LCA (CD45)
Pan T = CD3
Pan B = CD20
Many plasma cells rash differential?
Calvin's Zone has 8 Luscious Roses Folliculitis de Calvans or acne keloidalis nuchae Plasma cell balanitis (Zoons) \+ 8 L's + Rosacea; Lupus vulgaris (Tb) Lues (syphylis also Yaws, Pinta) Lymphoma, lymphocytoma cutis, MF, myeloma Lipoidica - NLD Leprosy Leishmaniasis LGV and granuloma venereum Lyme (erythema chronicum migrans or acrodermatitis chronica atrophicans)
Also; Morphoea Chancroid – plasma cells in deep zone seb derm in HIV pts has plasma cells ie first 5 Ls are same as in 8Ls and DRUGS list except first is lupus vulgaris rather than lupus and in that list the last 3 are; Light, Lichen, Lepidoptera
What are the features of and main DDs for the Pityriasiform spongiosis reaction pattern?
Focal Para, Spong, Lymphs, Red cells; Mounds of FOCAL parakeratosis Focal spongiosis with PAV; - Pseudopautrier microabscesses - focal Acanthosis - Often spongiotic Vesicles Superficial perivascular lymphocytic infiltrate - Often lymphocyte exocytosis Extravasated RBCs in pap dermis Rare eos, rare dyskeratosis
DDs
Pit rosea
Pityriasiform drug eruption
Superficial type of EAC
Pit lechenoides; pityriasiform spongiosis+lichenoid pattern
Sometimes – discoid eczema, lichen striatus
Which organisms cause chromoblastomycosis?
what is histo?
pigmented (‘demitaceus’) fungi e.g. Fonsy Cuddles Philippa (Fonsy has a motorbike with lots of chrome - chromo..) Fonsecaea spp Cladosporium carrionii Phialophora verrucosa Histo; pseudoepitheliomatous hyperplasia granulomatous infiltrate Medlar bodies (copper pennies)
Which organisms cause Phaeohyphomycosis?
pigmented (‘demitaceus’) fungi e.g. ABC or Curvy, Bipolar Alternative Alternaria Bipolaris Curvularia Spp.
What is the alternative name for pseudoepitheliomatous hyperplasia?
reactive epithelial hyperplasia
Looks a bit like SCC
Nb - not quite the dame as basaloid induction/follicular induction of epi seen overlying dermatofibroma which looks a bit like BCC (and is BerEP4 +ve)
What is your panel of special stains for a suppurative granuloma or other likely inefction?
1st look for clues e.g. plasma cells, Medlar bodies, hyphae PAS (fungus) gram (bacteria) Ziehl-Neelsen (Myco;AFB) Wade-Fite (M. leprae) Grocott (silver, fungus) Giemsa (spirochetes, leishmaniasis) \+/- Spirochete IHC (Treponemes)
How can the diagnosis of vitiligo be confirmed?
SOX-10 stain
shows no or few melanocytes
Good if uninvolved skin also present to compare
What are the stains for Mucin?
PAS and diastase
Alcian blue pH2.5
Colloidal iron
