Final - Derm Flashcards
Oculocutaneous Albinism (OCA)
Inherited disorder - melanocytes present, melanin production inadequate. Most of 4 main genotypes are autosomal recessive.
50% “type II” has loss of function in P gene (pink-eyed), 40% “type I” decreased tyrosinase activity.
Ocular involvement -> nystagmus, strabismus, and loss of visual acuity.
Acne Vulgaris
Involves sebaceous glands & hair follicles.
Non-inflammatory type has comedones.
- Open comedones are follicular papules with central keratin plug that has oxidized.
- Closed comedones follicular papules w/keratin plug trapped beneath epithelial surface.
Inflammatory acne has erythematous papules, nodules, and pustules.
4 Pathogenic components of Acne Vulgaris
Keratin plugging - blocks outflow of sebum due to changes of the infundibulum of the follicle
Hypertrophy - of the sebaceous glands, often result of hormonal stimulation
Colonization - of follicle by lipase-synthesizing bacteria *Propionibacterium acnes
Inflammation - of the follicle due to breakdown of the sebum into pro-inflammatory fatty acids.
Acne Rosacea
Cutaneous inflammation of the nose and malar aspects of the face
- flushing episodes
- telangiectasia & persistent erythema
- papule & pusture formation
- rhinophyma (permanent thickening of the nasal skin.
*Different amount & type of cathelicidin -> inappropriate activation of immune response, alternative processing of serene proteases
Cathelicidin in Acne Rosacea
- Initially expressed as a pro peptide that requires proteolytic processing to generate biologically active LL-37 peptide.
- Stratum corneum tryptic enzyme mediates this in the skin.
- LL-37 contributes to effective innate immunity -> bactericidal, chemotactic, antiogenic biological activities
- Expression of cathelicidin and SCTE (its proteolytic processing enzyme) increased in Acne Rosacea
- Increased expression of the biologically active LL-37 & several unusual isoforms in rosacea lesions.
Folliculitis
- Bacterial infection of hair follicles, usually Staph aureus*. (hot-tub folliculitis from inadequate disinfection)
- Infected hairs typically fall out
Cellulitis/Erysipelas/Abscess
Acute bacterial infxn of skin & subq tissue. *Usually S. aureus or GABHS.
- Pain & rapidly spreading erythema & edema
- Strep enzymes (streptokinase, hyaluronidase, DNAase) lead to faster spreading
- Fever, regional lymph node enlargement & lymphangitis (lymphatic dissemination, “blood poisoning” are possible)
- Erysipelas is a superficial cellulitis w/involvement of the dermal lymphatics.
- Occurs most frequently on face and legs.
Furucles (boils)
- Tender nodules from cutaneous infection with S. aureus.
- Nodules are more superficial and generally smaller than abscesses.
Carbuncles
- Collections of furuncles connected by subcutaneous tracts.
Impetigo/Ecthyma
- Superficial skin infection by Strep of Staph
- Vessicle/ bullae formation characteristic. Fluid weeps or erupts, then crusts **Honey Crusted Lesions*
- Exfoliative bullous lesions caused by staph toxin
- Ecthyma is an ulcerative form of impetigo
- Chronic nasal discharge, moist environment, poor hygiene are risk factors.
Erythema Marginatum
- Cutaneous manifestation of acute rheumatic fever*
- Post-infectious, immune-mediated complication of GABHS pharyngitis
- Lesions sharply demarcated areas of eythema w/central inclusion of normal-appearing integument.
- Lesions move rapidly across the skin in minutes to hours
Erythema Migrans
- Cutaneous manifestation of Borrelia burgdorferi! Lyme dz!
- Vector is Ixodes scapularis - deer tick
- EM is best clinical indicator of infection & first sign of the dz, occurs in 75% of infected.
- Red macule of papule occurs 3-32 days after initial bite. Area expands, maybe central clearing
- ~ 1/2 of pts develop multiple smaller lesions w/indurated centers. Cultured biopsies show spirochete, representing dissemination of the dz.
Molluscum Contagiosum
- Poxvirus skin infection. Largest pathogenic poxvirus in humans. Spread by direct contact
- Multiple firm, pink/purple/skin-colored papules w/umbilicated centers & a waxy core
- “Molluscum bodies” are ellipsoid cytoplasmic inclusions seen on Giemsa stain of the exudate.
- Inclusions occur in the stratum granulosum & stratum corneum
Verrucae/Warts
Skin lesions caused by HPV
- transmission by direct contact.
- spontaneous regression in 6-24 mos.
4 types
-Verruca vulgaris: most common type, typically on hands, 1cm papules w/rough, pebble-like verucoid surface.
-Verruca plana: flat warts occur on palmar surfaces & face, slightly elevated & smaller than the vulgarism.
-Verruca plantaris & palmaris: occur on soles & palms, scaly, 1-2cm, rough callus-like texture.
Condyloma acuminatum - venereal warts, HPV 6 & 11, on genitals, perigenital areas, perineum & anus. Soft, cauliflower or cocks-comb excresences.
Histology of Warts
Epidermal hyperplasia
- Papillomatous epidermal hyperplasia, often with undulant character
Koilocytosis
-*cytoplasmic vacuolization of more superficial cell layers creating pale halos around the nuclei
- prominent kerato-hyaline granules
