Rash Flashcards
What is a rash?
Inflammatory skin erruption
Differential diagnosis of a rash os primarily based on morphology of the lesion:
1) First identify the primary lesion, this is the lesion that is the typical element of the eruption.
2) Determine the global reaction patern.
3) Distribution of the lesions (diffuse, isolate, localized, regional, universal)
Primary lesion:
initial lesion that has not been altered by trauma or manipulation, and has not regressed.
Secondary lesion:
Develops as the disease evolves or as the patient damages the lesion. ex) rubbing, scratching, infections.
Primary lesions:
Bulla
Macule
Nodule
Papule
Patch
Petechiae
Plaque
Pustule
Vesicle
Wheal
Bulla:
A circumscribed, elevated lesion that measures ≥ 1cm and contains serous or hemorrhagic fluid (ex: larger blister)
Macule:
circumscribed, nonpalpable discoloration of the skin that measure < 1cm in diameter.
Nodule:
A palpable, solid, round ellipsoid lesion measuring ≥1cm; it differs from a plaque in that it is more substantive in its vertical dimension compared with its breadth.
Papule:
An elevated, solid lesion that measures <1cm in diameter
Patch:
A circumscribed, nonpalpable discoloration of the skin that measures ≥1cm.
Petechiae:
Nonblanching reddish macules representing extravascular deposits of blood, measuring ≤ 0.3cm (less than the size of a pencil eraser).
Plaque:
A palpable, solid lesion that measures ≥1cm
Purpura:
Nonblanching reddish macules or papules representing extravascular deposits of blood, measuring > 0.3cm.
Pustule:
A lesion that contains pus; may be follicular (centered around the hair follicle) or nonfollicular.
Vesicle:
A circumscribed, elevated lesion that measures <1cm & contains serous or hemorrhagic fluid (ex:small blister)
Wheal:
A round or annular (ring-like), edematous papule or plaque that is characteristically evanescent, disappearing within hours; may be surrounded by a flare or erythema. (ex: hive)
Secondary lesion:
Atrophy
Crust
Erosion
Lichenification
Scale
Scar
Ulcer
Atrophy:
A depression in the skin resulting from thinning of epidermis, dermis and/or subcutaneous fat.
Crust:
A collection of dried blood, serum, and/or cellular depris.
Erosion:
A focal loss of epidermis does not penetrate below the dermal-epidermal junction and, therefore, can heal without scarring.
Lichenification:
Thickening of the epidermis resulting from repeated rubbing, appearing as accentuation of the skin markings.
Scale:
Excess dead epidermal cells; scale may be fine, silvery, greasy, desquamative, or adherent.
Scar:
Abnormal formation of connective tissue, implying dermal damage.
Ulcer:
A focal loss of full-thickness epidermis and partial to fill thickness dermis, which often heals with scarring.
Papulosquamous eruptions (papules and plaques w/scales):
Folliculopapular eruptions: (perifollicular papules)
Dermal reaction patterns:
Purpura and petichiae:
Nonpalpable purpura:
Blistering disorders (vesicles, pustules, and bullae):
History in dermatology:
Include your standard HPI, past medical history, family medical history, social history, sexual history and the following questions:
When? (onset)
Where? (site of onset)
Does it itch or hurt? (symptoms)
How has it spread (pattern of spreading)? (Evolution)
How have the individual lesions changed? (evolution)
Provocative factors? heat, cold, sun, exercise travel history, drugs, pregnancy, seasonal changes
-Exposures at the site? changes to routine (laundry detergent, cosmetics, cleaning products?)
Previous treatment and response to treatment? (Topical systemic)
Constitutional symptoms? headache, fever, chills, weakness, malaise arthralgias, etc.
-More chronic ones: weight loss, weakness, malaise
Physical exam:
Genral shape: round, oval, polygonal, polycystic, annular (ring-shaped), iris, serpiginous (snakelike), umbilicated.
Size
Color
Margination: well defined, Ill defined
Palpation:
-Consistency (soft, firm, harm, fluctuant, board-like)
-Deviation in temp (hot, cold)
-Mobility
-Tenderness?
-Estimate the depth of the lesion (ex: dermal or subcutaneous)
Number: single or multiple lesions
Arrangement: Multiple lesions may be:
-Grouped: herpetiform, arciform, annular, reticulated (net-shaped), linear, serpiginous
-Disseminated: scattered discrete lesions
Confluence: yes or no
Distribution:
-Isolated?
-Localized vs. regional vs. generalized
-Pattern: symmetric, exposed areas, sites of pressure, intertriginous area, follicular localization, random, following dermatimes or blashko lines
Ruling out melanoma and dysplastic nevi:
1) Asymmetry
2) Irregular borders
3) Variegated color
4) Diameter: a lesion larger than 6mm is at higher risk for malignancy
5) Evolution/Enlargement: a lesion that changes over time is at higher risk for malignancy
Magnification with hand lens:
Hand lens (7 x magnification)
Binocular microscope (5x to 40x magnification)
Oblique lighting:
Used to view degrees of elevation or depression in a lesion. Done in a darkened room.
Subdued lighting:
Used to enhance the contrast between circumscribed hypopigmented or hyperpigmented lesions and normal skin.
Wood lamp:
356 nm ultraviolet long-wave light, “black light):
-Can pick up florescent pigments and subtle color
-Causes some superficial lesions to fluoresce.
-Vitiligo presents as amelanotic
-Tinea capitis and tinea versicolor can sometimes be visualized with wood lamp but not likely tinea corporis, as many references would suggest: depends on species of fungus: porphyrias, erythrasma, some bacterial infections (pseudomonas)
-Deep(raticular dermal) lesions typically do not flouresce under wood lamp
-Typically used by dermatologists, not necessary in naturopathic medicine
Diascopy:
Firmly pressing a microscopic slide or glass spatula over a lesion
Can assess if the red color of a macule is due to capillary dilation or extraversion of blood that does not blanch.
Dermoscopy:
Hand lens with built in lighting and magnification. Inspection of deeper layers of the dermis. Helpful to distinguish between benign and malignant lesions.
Patch testing:
Used to confirm a diagnosis of allergic contact sensitization and identify the agent that caused the allergic reaction.
Substances to be tested are applied to the skin in shallow cups (finn chambers), taped onto the skin and left in place for 24-48 hours. Contact hypersensitivity will show as a papular vesicular reaction that will develop within 48 to 72 hours when the test is read.
Prick testing:
Used to determine type I allergies.
A drop of a solution containing a small amount of allergen is placed on the skin and the skin is pierced through this drop with a needle.
A positive result would be a wheal appearing within 20 minutes.
Caution: the patient needs to be under constant supervision due to possibility of anaphylaxis.
Skin scraping:
Dermatophyte/KOH collection
-Microscopic examination for mycelia should be made of the roofs of the vesicles or of scales or in the hair in dermatophytosis.
The tissue os cleared with 10 to 30% KOH and warmed gently. Hyphae and spores can then be viewed.
Microbiology (culture & sensitivity) and specimen handling biopsy
*Note most of these clinical tests are performed by allergists or dermatologist, some ND’s offer prick testing and skin scraping, but a patient can be referred out for further evaluation
Biopsy:
Different tools can be used for different types of lesions.
Punch biopsy:
-Useful in the workup of cutaneous neoplasms, pigmented lesions, inflammatory lesions and chronic skin disorders.
-3 to 4 mm punch, a small tubular knife cuts through the epidermis, and subcutaneous tissue by rotating the tool.
Excisional biopsy (wide local excision):
-Surgical removal of a tumor and some normal tissue around it.
Atopic dermatitis:
Contact dermatitis:
Seborrheic dermatitis:
Dyshidrosis (Acute palmoplantar eczema):
Nummular dermatitis:
Pathophysiology:
The natural aging process, chronic venous stasis, bacterial colonization, certain drugs, and sensitization to contact allergens, most commonly metals (nickel sulfate, potassium dichromate, cobalt chloride), may compromise the cutaneous lipid barrier.[1] The release of cytokines (i.e., IFN-g and IL-17) results in increased recruitment of T cells, dendritic cells, and Langerhan’s cells, eventually leading to epidermal hyperplasia and the development of characteristic lesions.[6]
Epidemiology: affecting predominantly females 15 to 25 years of age and males 50 to 65 years of age. Prevalence ranges from 0.1% to 9.1%
Time course: Patches can last for weeks to months, and flare-ups or episodes can repeatedly happen over a long period of time.
Symptoms & signs:
Coin shaped lesions on the skin on the trunk, hands, and legs
The lesions are brown, pink or red
Itching and burning of the lesions
Lesions often appear like a skin injury, such as a burn, abrasion (from friction), or insect bite
Oozing of fluid from the lesions and crusting
Diagnostics:
Diagnosis involves review of medical history and visual skin inspection.
-Allergy skin test: To determine the substances causing allergies.
-Patch test: To determine a specific substance which causes allergic inflammation.
-Skin biopsy: To rule out other possible causes e.g. infection.
