What is a Keloid
An irregular raised lesion resulting from scar tissue hypertrophy (commonly seen in African Americans)
What is Urticaria and what are its characteristics?
Hives: Intensely prurtic wheals that form after mast cell degranulation...( Wheals have a clearing center with red surrounding it)
What is common of atopic dermatitis?
Pruritic eruption, common on skin flexures---associated with other atopic diseases like asthma and allergic rhinitis (Type I)
What are characteristic lesions seen in Psoriasis?
Salmon pink or silver scaly papules and plaques, esp on knees and elbows.
What histological changes are seen in Psoriasis?
Increased stratum spinosum and decreased stratum granulosum
What is Seborrheic keratosis?
Flat greasy pigmented squamous epithelial proliferation with keratin filled cysts...Common benign neoplasm of elderly.
What is Albinism?
Normal melanocyte number with decreased melanin production due to decreased tyrosinase activity.
Failure of NCCells to migrate
What is Vitiligo?
Irregular areas of complete depigmentation caused by a decreased number of melanocytes
What is Necrotizing Fasciitis?
Deeper tissue injury than cellulitis, usually caused by anaerobic bacteria or S. pyogenes.
What is characteristic of Necrotizing Fasciitis?
Crepitus due to increased methane or CO2 production from anaerobes---seen in 'flesh-eating bacteria
What is Staphylococcal Scalded Skin Syndrome?
Exotoxic damage from S. aureus that destroys KERATINOCYTE attachments in the stratum GRANULOSUM
What is characteristic of SSSS?
Fever, generalized rash and sloughing of the upper layers of the epidermis due to destroyed keratinocyte attachments.
What is characteristic of Hairy Leukoplakia?
White painless patches on the tongue that CANNOT be scraped off---
What type of antibodies are seen in Pemphigus vulgaris?
Anti-epithelial cell antibodies (IgG) against DESMOSOMES---potentially fatal.
What is a characteristic skin lesion illustrated in Pemphigus vulgaris?
Acantholysis--intraepidermal bullae form esp on skin AND mouth
What is a positive Nikolsky's sign and where is it seen?
Separation of the epidermis upon manual stroking--seen in pemphigus vulgaris
What are antibodies directed against in bullous pemphigoid?
Hemidesmosomes of the epidermal basement membrane (Antibodies are 'BULLOW' the BM)
What is the difference in immunofluorescent staining pattern between pemphigus vulgaris and bullous pemphigoid?
Vulgaris has IM staining positive throughout but Bullous pemphigoid has a linear staining only along the BM
What is are two clinical differences between Pemphigus vulgaris and Bullous pemphigoid?
Pemphigoid SPARES the oral mucosa and has a negative Nikolsky's sign... the patient is also otherwise healthy. Vulgaris can be life threatening.
What is characteristic of dermatitis herpetiformis?
Pruritic papules and vesicles... Deposits of IgA are seen at the tips of dermal papillae
What types of lesions are commonly seen in Erythema multiforme?
TARGET lesions, red papules with a clear ring around them.
Also macules, papules and vesicles
What is the next step up from Erythema multiforme that is in addition characterized by fever, bulla and necrosis, sloughing of skin and high mortality rate?
Stevens Johnson syndrome
What is Toxic Epidermal necrolysis?
Like SJS but with more severity and greater epidermal involvement.
What are drug commonly known to cause SJS?
Carbamazepine, phenytoin and phenobarbitol
What is seen on histology of Lichen Planus?
Sawtooth infiltration of lymphocytes at dermal-epidermal junction.
What is Actinic Keratosis?
Premalignant lesions to SCC caused by sun exposure.
Small, rough and erythematous or browning papules
What is the risk of developing SCC proportional to in Actinic Keratosis?
Level of epithelial dysplasia
What are the associated findings in pts with acanthosis nigricans?
Hyperlipidemia, esp in Cushings or DM
What are several diseases associated with Erythema nodosum?
What IS erythema nodosum?
Inflammatory lesions of subcutaneous fat, usually on anterior shins (can resemble bruising.)
What is characteristic of the lesions on SCC?
Usually on hands or face, they are ulcerative red lesions...
Invade but rarely metastasize
What are the associated causes of melanoma?
Sunlight exposure, esp intermittent burning
Fair skinned persons are at higher risk
What are the ABCDs of melanoma?
Diameter (>6mm is suspicious)
Any of these changes in a mole should be investigated.
---****---What is the cause of the redness if a lesion blanches on diascopy?
Dilated capillaries... Pressing of the glass slide pushes the blood out of the capillaries and causes the blanching (Telangiectasia)
What is the cause of redness if a lesions does NOT blanch on diascopy?
Damage to the capillaries or post-capillary venues, which has caused leakage of blood that will not disappear
What is a granuloma?
Collection of histiocytes with or without epitheliod cells and multinucleated giant cells.
What is leukocytoclasis?
Fragmentation of leukocytes commonly seen in vasculitis---does not blanch on diascopy
What is the gold standard for diagnosis of Allergic Contact dermatitis?
A patch test, where a patch of the suspected substance is applied to the skin to look for the resulting dermatitis.
What type of hypersensitivity is cutaneous leukocytoclastic Vasculitis?
Type III---immune complexes deposit in the skin 7-10 days after inciting agent
What condition is angioedema an exacerbation of?
Hives or Urticaria---can lead to swelling of lips, eyes
Difference between Urticaria and Erythema multiforme?
Urticaria: lesions are less than 24 hours, and new lesions show up daily... associated w/ edema
EM: Lesions are fixed and all show up at once usually after 7 days. No edema
What condition are anti-desmoglein-3 antibodies found in?
PVulgaris... ONLY the basal layer of skin and below remains intact.
In what condition are anti-desmoglein-1 antibodies found?
P-Folaceus---only the corneum is sloughed off
What is the characteristic lesion seen in LYME disease patients?
Bulls-eye lesion, with an expanding red region from which B-Burgdorferi can be isolated. (Erythema chronicum migrans)
What immune substance does the spirochete in LYME disease induce?
TNF--leads to fever and inflammation
What is the acronym for remembering associated features of LYME disease?
BAKE a key LYME pie!
What is a typical presentation of a Scabies infected patient?
Erythematous papules and burrows esp in the finger webs of a patient in a massive cluster of people, esp homeless or prisoners.
How is scabies diagnosed?
With the scabies prep or scraping skin using a scalpel with mineral oil and inspecting it for mites or eggs.
What is Roseola Infantum AKA?
Maculo-papulo rash with high fever but otherwise the child feels fine.
What is characteristic of Rubella infection?
Cranial-caudal development of macular-papular rash (rapidly) with tender cervical lymph nodes and low-grade fever
What is the real danger with Rubella infections?
It is a TORCHeS infection associated with congenital problems
What disease is Measles associated with years after the rash occurred?
Subacute sclerosing Panencephalitis
What is Asboe-Hansen's sign?
When bullae move laterally in the skin with pressure...
Seen in pemphigus vulgaris