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What are the transmission route for warts and molluscum?
What are the clinical features of verrucae?
Verruca vulgaris-->MC ( the dorsal surfaces and periungual areas of the hand)Verruca plana, or flat wart--> face or the dorsal surfaces of the hands. Verruca plantaris and verruca palmaris. Rough, scaly lesions may reach 1 to 2 cm in diameter, coalesce, and be confused with ordinary calluses. Condyloma acuminatum--> cauliflower-like masses that occasionally reach many centimeters in diameter
What is the histological features of the wart?
- Verrucous or papillomatous epidermal hyperplasia Cytoplasmic vacuolization (koilocytosis) involving the more superficial epidermal layers, producing perinuclear haloes Electron microscopy --> numerous viral particles within nuclei. Condensed keratohyaline granules and jagged eosinophilic intracytoplasmic keratin aggregates as a result of viral cytopathic effects
What is the morphology of Molluscum virus?
brick shaped, has a dumbbell-shaped DNA core
What are the morphological features of molluscum?
Flesh-colored umbilicated papuleOn the skin or mucosa of trunk and anogenitalA curd-like material can be expressed from the central umbilication. Smearing this material onto a glass slide and staining with Giemsa reagent often shows diagnostic molluscum bodies.verrucous epidermal hyperplasiaMB: Large , ellipsoid, homogeneous, cytoplasmic inclusion in cells of the stratum granulosum and the stratum corneum In the H&E stain, these inclusions are eosinophilic in the blue-purple stratum granulosum and acquire a pale blue hue in the red stratum corneum.
What is the mcc and mc place for impetigo?
- face and hands
What are the clinical features of impetigo?
It presents as an erythematous macule, but multiple small pustules rapidly supervene. As pustules break, shallow erosions form, covered with drying serum, giving the characteristic clinical appearance of honey-colored crust. If the crust is not removed, new lesions form about the periphery and extensive epidermal damage may ensue
What is the characteristic microscopic feature of impetigo?
Accumulation of neutrophils beneath the stratum corneum, often producing a subcorneal pustule
What is the pathogenesis of impetigo?
- 1) Bacterial species in the epidermis evoke an innate immune response 2) Blister formation in impetigo is related to bacterial production of a toxin that specifically cleaves desmoglein 1, the protein responsible for cell-to-cell adhesion within the uppermost epidermal layers.(In pemphigus foliaceus, which has a similar plane of blister formation, desmoglein 1 is compromised by an autoantibody)
- No Dermis involvement--> no scar
What are the features of Hidradenitis suppurativa?
- 1) chronic, suppurative, subcutaneous process that results from occlusion of follicles, secondary inflammation and sometimes infection of pilosebaceous and (secondarily) apocrine glands.
- 2) Not contagious or related to poor hygiene
- 3) MC axilla> genital
- 4) Small painful subcutaneous nodules (rupture, pus, sinus)
Acne vulgaris in adolescents is believed to occur as a result of ..........
physiologic hormonal variations and alterations in hair follicles, particularly the sebaceous gland.
Which drugs are most likely to contribute to acne?
What are the types of acne?
- noninflammatory and inflammatory.
- nonInflammatory: open and closed comedones. Open comedones are small follicular papules containing a central black keratin plug. This color is the result of oxidation of melanin pigment.
- Closed comedones are follicular papules without a visible central plug. Because the keratin plug is trapped beneath the epidermal surface, these lesions are potential sources of follicular rupture and inflammation.
- Inflammatory acne is characterized by erythematous papules, nodules, and pustules
What are the four component that may contribute to acne?
- (1) changes in keratinization of the lower portion of the follicular infundibulum with the development of a keratin plug blocking outflow of sebum to the skin surface
- (2) hypertrophy of sebaceous glands with puberty or increased activity due to hormonal stimulation
- (3) lipase-synthesizing bacteria (Propionibacterium acnes) colonizing the upper and midportion of the hair follicle, converting lipids within sebum to pro-inflammatory fatty acids
- (4) inflammation of the follicle associated with release of cytotoxic and chemotactic factors.
How is the inflammation in Acne?
- Variable lymphohistiocytic infiltrates are present in and around affected follicles, and extensive acute and chronic inflammation accompanies follicular rupture.
- Dermal abscesses may form in association with rupture and gradual resolution, often with scarring, ensues.
What is the earliest inflammatory phases of acne?
bacterial lipases of Propionibacterium acnes break down sebaceous oils, liberating highly irritating fatty acids
What is a rationale for administration of antibiotics to individuals with inflammatory acne?.
Inhibition of lipase production
What is the most important mechanism of action of isotretinoin in acne/
- Shrinkage of sebaceous glands and a marked attenuation of sebum secretion.
- The decrease in sebum results in the inhibition of the sebum-dependent P. acnes, which is a key promoter of inflammation in acne vulgaris.
- Oral isotretinoin also inhibits comedogenesis by fostering keratinocyte differentiation and by normalizing desquamation
What are the onychomycosis?
- DSO (MC--> T.rubrum)
- PSO(associated with AIDS)
- White Superficial (T.mentagrophytes)
How is Onychomycosis diagnosed and treated?
- KOH--> dermatophytic hyphae and arthrospores
- Tx: Oral Terbinafine (check LFT) and Itraconazole
What is the difference between Eryseplas and cellulitis?
- Eryseplas--> well-defined, raised superficial dermis and lymphatics, Involve the ear, acute onset
- Cellulitis--> poor defined, Deep dermis and subQ fat, does not involve the ear, subacute
(both mc in lower extremity)
What is the mc location for seborrheic dermatitis?
regions with a high density of sebaceous glands, such as the scalp, forehead (especially the glabella), external auditory canal, retroauricular area, nasolabial folds, and the presternal area
True or false: Seborrheic dermatitis is a disease of sebaceus gland
What is the gross morphology of seborrheic dermatitis?
- The individual lesions are macules and papules on an erythematous-yellow, often greasy base, typically in association with extensive scaling and crusting.
- Fissures may also be present, particularly behind the ears.
- Dandruff is the common clinical expression of seborrheic dermatitis of the scalp. In infants, seborrheic dermatitis presents as cradle cap but can also be part of a disorder known as Leiner disease, in which the condition is generalized and associated with diarrhea and failure to thrive.
What is the histology of seborrheic dermatitis?
- Share histologic features with both spongiotic dermatitis and psoriasis, with earlier lesions being more spongiotic and later ones more acanthotic.
- Mounds of parakeratosis containing neutrophils and serum are present at the ostia of hair follicles (so-called follicular lipping).
- A superficial perivascular inflammatory infiltrate generally consists of an admixture of lymphocytes and neutrophils. With human immunodeficiency virus infection, apoptotic keratinocytes and plasma cells may also be present
Where do we see severe seborrheic dermatitis?
What is the pathogenic organism in seborrheic dermatitis?
What is the cause of SD in Parkinson's disease?
increased sebum production secondary to dopamine deficiency
What are the features of Chigger bite?
- Larval stage of Trombiculid mite
- (mature mite is read to orange)
- Grassland, lake, forest, stream
- Pruritc grouped lesions at ankle or waistline
- DOES NOT BURROW INTO THE SKIN
What are the features of Sarcoptes Scabie?
- Whitish-brown eight-legged mite, shaped much like a turtle.
- Female causes the clinical manifestations
- Burrowing is facilitated by secretion of proteolytic enzymes which cause keratinocytic damage.
- When fertilized, the female burrows quickly into the epidermis to the level of the stratum granulosum, where it extends its burrow by approximately 2 mm each day, lays two at a time to a total of 10 to 25, and dies in place after one to two months.
- Larvae hatch in three days, molt three times, leave the burrow for the surface, copulate, and continue the cycle
- Survive 24-36 hour outside body
- Person to person by direct contact(including sexual)
What is the cause of symptoms in Scabies?
pruritus is the result of a delayed type-IV hypersensitivity reaction to the mite, mite feces, and mite eggs
What is the IP in scabies infection?
- 3 week after primary infestation
- 3 days after infestation with a prior history of infestation
What are the manifestations of scabies?
- 1) Small, erythematous, nondescript papule, often excoriated and tipped with hemorrhagic crusts
- 2) Burrow
- 3) Sides and webs of the fingers, the flexor aspects of the wrists, the extensor aspects of the elbows, anterior and posterior axillary folds, the skin immediately adjacent to the nipples (especially in women), the periumbilical areas, waist, male genitalia (scrotum, penile shaft, and glans), the extensor surface of the knees, the lower half of the buttocks and adjacent thighs, and the lateral and posterior aspects of the feet.
- 4) The back is relatively free of involvement, and the head is spared except in very young children.
- 5) Family involvement
What is the treatment for scabies?
permethrin 5% cream and oral ivermectin
What are the three types of lice?
- The three varieties of lice specifically parasitic for humans are Phthirus pubis (picture A, crab louse), Pediculosis humanus capitis (picture B, head louse), and Pediculosis humanus corporis (picture C, body louse).
What are the features of head lice?
- Asymptomatic or may complain of scalpand/or neck pruritus.
- In cases of active infestation, louse eggs (nits) are found on hair shafts and crawling nymphs and adult lice are present.
- Wet-combing is a useful technique for locating adult lice or nymphs. The presence of nits alone does not confirm active infestation.
- Direct contact with the head of an infested person
What are the features of pediculus corporis?
- Unlike pediculosis capitis and pediculosis pubis, the organism lives on the clothing, rather than on the skin of infested individuals.
- The body louse can serve as a vector for epidemic typhus, trench fever, and relapsing fever.
- Patients with pediculosis corporis often complain of pruritus. Excoriations and postinflammatory hyperpigmentation are typical signs of infestation.
- The diagnosis is made through the visualization of lice or nits on clothing.
- Treat clothing
What are the features of pubic louse?
- 1)Sexual contact.
- 2) Pubic and axillary pruritus.
- 3) The diagnosis is made through the visual identification of lice and nits.
- 4) Individuals with pediculosis pubis should be screened for other STI
- 5) Sexual partners should be treated simultaneously.
- Infestation of the eyelashes may occur in individuals with pediculosis pubis or in children who are in close contact with infested individuals. Although the majority of children with this diagnosis acquire the infestation via non-sexual contact, the possibility of sexual abuse should be considered.
What are the features of bedbug?
- Bedbugs are reddish brown and similar in size to a dog tick. They have flat oval bodies and retroverted mouthparts. The eyes are widely separated.
- Attracted by warmth and carbon dioxide
- Infest whole of a facility
- Eat blood at night from exposed skin areas
- Wheal with a central hemorrhagic punctum
- series of bites in a row