Pathology Skin

producing protective keratin protein and cytokines

epidermis

• dendrocytes in the dermis
• Langerhans cells in the epidermis

those that expression of cutaneous lymphocyte-associated antigen (CLA)

• Neuroendocrine cells within the epithelial basal cell layer.
• These may serve as mechanoreceptors or possibly provide neuroendocrine function in skin.

They harbor protected niches of epithelial stem cells

• Micro
• Micro
• Macro
• Macro

• Nodule (dom shaped)
• Plaque (flat raised)
• Patch (non-raised change in pigmentation)
• Bullae (fluid filled)

• Macule (flat colored)
• Papule (raised flat or dom-shpaed)
• Vesicle (fluid filled)

• Blister (both vesicle and bullae)
• Pustule (pus filled)
• Wheal (dermal edema+erythema and itchy, transient, variable blanching)
• Scale (Dry, horny, platelike excrescence; usually the result of imperfect cornification)
• Excoriation (Traumatic lesion breaking the epidermis and causing a raw linear area (i.e., deep scratch); often self-induced)
• Lichenification (Thickened and rough skin characterized by prominent skin markings ; usually the result of repeated rubbing)
• Onycholysis (Separation of nail plate from nail bed)

Lichenification

Imperfect cornification

• Wheal (Dermal, macroscopic)
• Spongiosis (intercellular in epidermis, micro)
• Ballooning or hydropic swelling (intracellular in epidermis, micro)

• Acanthosis: Diffuse epidermal hyperplasia
• Hypergranulosis: Hyperplasia of the stratum granulosum, often due to intense rubbing
• Hyperkeratosis: Thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin

• Erosion: Discontinuity of the skin showing incomplete loss of the epidermis
• Ulceration: Discontinuity of the skin showing complete loss of the epidermis revealing dermis or subcutis

viral infection

Acantholysis

Abnormal, premature keratinization within cells below the stratum granulosum

Infiltration of the epidermis by inflammatory cells

Lentiginous

Keratinization with retained nuclei in the stratum corneum. On mucous membranes, parakeratosis is normal.

Surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae

Formation of vacuoles within or adjacent to cells; often refers to basal cell–basement membrane zone area

1. Rusoela: <2 years, three to five days of fever>40 that resolves abruptly and is followed by development of a rash.  a blanching macular or maculopapular rash develops, starting on the neck and trunk and spreading to the face and extremities  (also FC)

2. Measles: 3C+Koplik spot (dissapears before rash), stimson line (transverse line in the palpebra--> blanching erythematous "brick-red" maculopapular rash beginning in the head and neck (above the hairline) area and spreading centrifugally to the trunk and extremities. RASH is accompanied by FEVER

3. Rubella: Mild prodromal, retroauricular, posterior cervical, posterior occipital LAP+ rash begins on face, less severe than measles, rose-colored spot on the soft palate (Forschheimer spots)

• 4. Erythema infectiosum (Fifth disease): school aged children, low grade fever, three stage rash--> erythematous cheek (slapped cheek)+ circumoral pallor--> symmetric maculopapular truncal rash--> lacy, reticulated rash
• 5. VZV: prodromal precede rash by one day--> rash begin on trunk (Papule--> vesicle--> ulcer--> crust)/ pruritus/ different stage of the lesion

• 6. Scarlet fever: diffuse erythema that blanches with pressure, with numerous small (1 to 2 mm) papular elevations, giving a "sandpaper" quality to the skin. Starts on the head and neck and is accompanied by circumoral pallor and a strawberry tongue. Desquamates; the palms and soles are usually spared. Most marked in the skin folds . Linear petechial character in the antecubital fossae and axillary folds, known as Pastia's lines 
•   

• 1. Rusoela: <2 years, three to five days of fever>40 that resolves abruptly and is followed by development of a rash.  a blanching macular or maculopapular rash develops, starting on the neck and trunk and spreading to the face and extremities  (also FC)

• Rubella: Mild prodromal, retroauricular, posterior cervical, posterior occipital LAP+ rash begins on face, less severe than measles, rose-colored spot on the soft palate (Forschheimer spots)

• 2. Measles: 3C+Koplik spot (dissapears before rash), stimson line (transverse line in the palpebra--> blanching erythematous "brick-red" maculopapular rash beginning in the head and neck (above the hairline) area and spreading centrifugally to the trunk and extremities. RASH is accompanied by FEVER

• Erythema infectiosum (Fifth disease): school aged children, low grade fever, three stage rash--> erythematous cheek (slapped cheek)+ circumoral pallor--> symmetric maculopapular truncal rash--> lacy, reticulated rash

• Scarlet fever: diffuse erythema that blanches with pressure, with numerous small (1 to 2 mm) papular elevations, giving a "sandpaper" quality to the skin. Starts on the head and neck and is accompanied by circumoral pallor and a strawberry tongue. Desquamates; the palms and soles are usually spared. Most marked in the skin folds . Linear petechial character in the antecubital fossae and axillary folds, known as Pastia's lines   

Capitis

• hairs within the patch break off a millimeter or two above the level of the scalp
• MC--> m.canis
• fluoresce bright green
• Ectothrix

• MC in US
• Black
• T.Tonsurans
• Human to human
• No florescence
• Endothrix

• T.Schoenleini
• initially develop perifollicular erythema on the scalp, which progresses to the characteristic finding of concave, cup-shaped yellow crusts called scutula
• Endothrix
• Blue silver florescence

• T.rubrum
• Central clearing
• Raised peripheral erythematous active lesion
• Cruris DOES NOT INVOLVE SCROTUM (CANDIDA INVOLVES SCROTUM)

• Acute(vesicle)--> T.mentagrophytes
• Chronic (plus manuum, nail, scaly)--> T.rubrum

• C.minutismum
• MC interdigital> groin, axilla
• Coral red florescence

• hypopigmented, hyperpigmented, or erythematous macules and patches. The most common areas of involvement include the upper trunk and proximal upper extremities
• Lipid-dependent malassezia furfur
• Spaghetti and meat ball (curvaed hyphae and clusters of conidia)