AN APPROACH TO DERMATOLOGICAL DIAGNOSIS Definitive diagnosis may require the information provided by a complete history, physical examination, laboratory tests, and histopathologic analysis. Here is an outline of a logical step-by-step approach to dermatologic diagnosis
Anamnesis History of skin lesions. Seven key questions: When did it start? Does it itch, burn, or hurt? Where on the body did it start? How has it spread? (pattern of spread) How have individual lesions changed? (evolution) Provocative factors? (patients occupation, immediate environment, seasonal variations, physiological states, foods, prescription or nonprescription drugs etc.) Previous treatment(s).
Anamnesis General history of present illness as indicated by clinical situation, with particular attention to constitutional and prodromal symptoms: 1. Acute illness syndrome (fever, sweats, chills, headache, nausea, vomiting, etc.)? 2. Chronic illness syndrome (fatigue, anorexia, weight loss, malaise)? 3. Review of systems. 4. Past medical history (operations, illnesses, allergies, medications, habits, atopic history). 5. Family medical history (particularly of skin disorders and of atopy). 6. Social history (occupation, hobbies, exposure, travel). 7. Sexual history.
Physical Examination General physical examination as indicated by clinical presentation and differential diagnosis, with particular attention to vital signs, lymphadenopathy, hepatomegaly, splenomegaly, joints.
Physical Examination Dermatologic examination – detailed physical examination of skin, hair, and mucous membranes. A. Four cardinal features: 1.Distribution (be sure to examine scalp, mouth, palms and soles): a.Extent or involvement: circumscribed, regional, generalized, universal? What percentage of the body surface is involved (the palm is roughly equivalent to 1%)? b.Pattern: symmetry, exposed areas, sites of pressure, intertriginous areas? c.Characteristic location: flexural, extensor, intertriginous, glabrous, palms and soles, dermatomal, trunk, lower extremities, exposed areas, etc.? 2.Type of lesion: macule, papule, nodule, vesicle, etc.? 3.Shape of individual lesions: annular, iris, arciform, linear, round, oval, umbilicated, etc.? 4.Arrangement of multiple lesions: isolated, scattered, grouped, herpetiform, zosteriform, annular, arciform, linear, reticular, etc.?
Physical Examination B. Three major characteristics: 1.Color: a. If diffuse: red, brown, gray-blue, orange-yellow, etc.; or if circumscribed: red, violaceous, orange, yellow, lilac, livid, brown, black, blue, gray, white, etc.? b. Does color blanch with pressure (diascopy test)? c. Woods lamp examination of pigmentary alterations: Is contrast enhanced? 2.Consistency and feel of lesion: soft, doughy, firm, hard, infiltrated, dry, moist, mobile, tender? 3.Anatomic component(s) of skin primarily affected: Is the process epidermal, dermal, subcutaneous, appendageal, or a combination of these?
Physical Examination Special procedures for dermatologic diagnosis are: palpation of the lesion – reveals the consistence, texture, deepness, stratification, infiltrated character, mobility, temperature, fluctuation, etc. diascopy or vitropressure reveals dermal modifications (apple jelly sign – hyaline yellowish-brown color of papules and nodules), vascular changes (erythema, purpura, telangiectasia) instrumental dermatoscopy – important for pigmentary, vascular, neoplastic lesions, etc. raclage of lesions reveals hyperkeratotic scales (dermatomycosis) and parakeratotic scales (psoriasis), grattage triad in psoriasis (oil spot, terminal film, pinpoint dots of blood – bloody dew), Besniers sign in lupus erythematosus, latent desquamation in tinea versicolor dermographism - white, red and mixed type, persistency, elevation level appreciation of pain, temperature, touch perception (an important sign in leprosy) appreciation of sebaceous and sweat glands function (for acne, ichthyoses, dishidrosis, etc.)
Physical Examination Specific instrumental and laboratory investigations confirming dermatologic diagnosis: skin biopsy (histopathologic analysis) Grams stain (microscopic examination), cytologic preparation, bacteriologic and fungal cultures confirming the diagnosis of scabies patch testing to confirm contact dermatitis, etc.
DERM ABC - SKIN LESIONS Primary lesions Lesion DescriptionExample MaculeA flat, circumscribed area of altered skin colorVitiligo, pityriasis versicolor Papule Plaque A small, circumscribed elevation of the skin Elevated solid confluence of papules Mollusc.contagiosum Psoriasis NoduleA solid, circumscribed elevation whose greater part lies beneath the skin surface Erythema nodosum WealA transient, slightly raised lesion, usually with a pale centre and a pink margin Urticaria VesicleA small, circumscribed, fluid-containing elevation Eczema, herpes simplex BullaSimilar to vesicle but largerPemphigus, bullous pemphigoid PustuleA collection of pusAcne, impetigo
DERM ABC - SKIN LESIONS Secondary lesions ScaleThickened, loose, readily detached fragments of stratum corneum Psoriasis, ichthyosis, pityriasis versicolor CrustDried exudateImpetigo, eczema ExcoriationA shallow abrasion often caused by scratchingAtopic dermatitis UlcerAn excavation due to loss of tissue including the epidermal surface Venous stasis ulceration ScarA permanent lesion that results from the process of repair by replacement with connective tissue CLE LichenificationAreas of increased epidermal thickness with accentuation of skin Atopic dermatitis ErosionA moist, circumscribed, usually depressed lesion that results from loss of all or a portion of the viable epidermis Pemphigus, eczema FissuresLinear cleavages or cracks in the skin and may be painful Palmar/plantar psoriasis, tinea pedis Macule (sec.)A flat, circumscribed area of altered skin colorAfter any primary lesion
Macula A macule is a circumscribed, flat lesion that differs from surrounding skin because of its color. Macules may have any size or shape. They may be: Dyschromic hyperpigmented (darker skin) – junctional nevi, café au lait (neurofibromatosis) hyperpigmented (darker skin) – junctional nevi, café au lait (neurofibromatosis) hypopigmented (lighter skin) – vitiligo, tuberous sclerosis hypopigmented (lighter skin) – vitiligo, tuberous sclerosis Vascular by capillary dilatation inflammatory – roseola (less than 1cm diameter) seen in secondary syphilis; erythema (greater than 1cm diameter) seen in eczema, drug-induced; erythroderma (involving all skin surface) seen in psoriasis, lichen planus, drug-induced, etc.; inflammatory – roseola (less than 1cm diameter) seen in secondary syphilis; erythema (greater than 1cm diameter) seen in eczema, drug-induced; erythroderma (involving all skin surface) seen in psoriasis, lichen planus, drug-induced, etc.; non-inflammatory – telangiectasis (permanent dilatation of capillaries that may or may not disappear with application of pressure) seen in lupus eruthematosus, dermatomyositis, rosacea, etc. non-inflammatory – telangiectasis (permanent dilatation of capillaries that may or may not disappear with application of pressure) seen in lupus eruthematosus, dermatomyositis, rosacea, etc. Vascular by red cell extravasation or purpuric macules (dont disappear or blanch by pressure) – petechiae (less then 5 mm); purpura (greater than 5 mm); ecchymoses are larger, bruiselike purpuric lesions, all are seen in vasculites
Papula A papule is a small solid, elevated lesion less than 0,5 cm in diameter. The elevation can be a result of metabolic deposits, localized hyperplasia of cellular components of the epidermis or dermis, or localized cellular infiltrates in the dermis. Papules may have a variety of shapes. They may be: acuminate (miliaria rubra); acuminate (miliaria rubra); surmounted with scale of keratin (secondary syphilis); surmounted with scale of keratin (secondary syphilis); dome-shaped (molluscum contagiosum); dome-shaped (molluscum contagiosum); flat-topped (lichen planus). flat-topped (lichen planus). Papules by color: red – psoriasis; copper – secondary syphilis; violet – lichen planus; yellow – xanthomatosis. Papules may be follicular and perifollicular – acne, folliculitis, Dariers disease.
Plaque Is a mesa-like elevation that occupies a relatively large surface area (more than 0,5 cm in diameter) in comparison with its height above skin level. Plaques are often formed by a confluence of papules, as in psoriasis. The typical psoriatic lesion is a raised, erythematous plaque with layers of silvery scale.
Nodule Is a palpable, solid, round or ellipsoidal lesion. Depending upon the anatomic component(s) primarily involved, nodules are of five main types: 1. epidermal (keratoacanthoma, verruca vulgaris, basal cell carcinoma); 2. epidermal-dermal (nevi, malignant melanoma, invasive squamous cell carcinoma, mycosis fungoides); 3. dermal (granuloma annulare, dermatofibromas); 4. dermal-subdermal (erythema nodosum, superficial thrombophlebitis); 5. subcutaneous (lipomas). Nodules in the dermis and subcutis may indicate systemic disease and result from inflammation, neoplasms, or metabolic deposits in the dermis or subcutaneous tissue. For example, late syphilis, tuberculosis, the deep mycosis, xanthomatosis, lymphoma, and metastatic neoplasms all can present as cutaneous nodules. A gumma is the granulomatous nodular lesion or tertiary syphilis and leproma is the same in leprosy
Wheals A wheal is rounded or flat-topped elevated lesion that is characteristically evanescent, disappearing within hours. The epidermis is not affected: there is no scaling. The borders of a wheal, although sharp, are not stable, and in fact move from involved to adjacent uninvolved areas over a period of hours. These lesions, also known as hives or urticaria, are the result of edema in the upper portion of the dermis. Wheals are pale red in color, but if the amount of edema is sufficient to compress superficial vessels, they may be white, especially in the center. Wheals may be tiny papules 3-4 mm in diameter, as in cholinergic urticaria, or giant erythematous plaques of cm, as in some cases of urticaria caused by penicillin hypersensitivity. Wheals occur in many shapes: round, oval, serpiginous, annular. Stroking of the skin may produce wheals in some normal persons; this phenomenon is called dermographism and is one of the physical urticarias. When it is associated with significant itching, it is called symptomatic dermographism. Angioedema is a deep, edematous urticarial reaction that occurs in areas with very loose dermis and subcutaneous tissue, such as the lip. It may occur on the hands and feet as well, and may cause grotesque deformity. A careful search should be made for laryngeal edema, which may cause airway obstruction.
Vesicles and bullae A vesicle is a circumscribed, elevated lesion that contains fluid. Often the vesicle walls are so thin that they are translucent and the serum, lymph, blood, or extracellular fluid is visible. A vesicle with a diameter greater than 0,5 cm is a bulla. Vesicles and bullae arise from cleavage at various levels of the skin; the cleavage may be within the epidermis (epidermal), or at or below the dermal-epidermal interface (subepidermal). Cleavage just beneath the stratum corneum produces a subcorneal vesicle or bulla, as in impetigo. Intraepidermal vesication may result from intercellular edema (spongiosis), as characteristically seen in delayed hypersensitivity reactions of the epidermis (contact eczematous dermatitis) and in dishidrotic eczema. Spongiotic vesicles may be detectable microscopically but may not be clinically apparent as vesicles.
Vesicles and bullae Loss of intercellular bridges, or desmosomes, is known as acantholysis, and this type of intraepidermal vesication is seen in pemphigus vulgaris, where the cleavage is usually just above the basal layer. In pemphigus foliaceus the cleavage occurs just below the sub-corneal layer. Viruses cause a curious ballooning degeneration of epidermal cells, as in herpes zoster, herpes simplex, variola, and varicella. Viral bullae often have a depressed (umbilicated) center. Pathologic changes at the dermal-epidermal junction may lead to subepidermal vesicles and bullae, as are seen in pemphigoid, bullous erythema multiforme, porphyria catanea tarda, dermatitis herpetiformis, and some forms of epidermolysis bullosa.
Pustule A pustule is a circumscribed, raised lesion that contains a purulent exudate (pus). Pus, composed of leukocytes with or without cellular debris, may contain bacteria or may be sterile, as in the lesions of pustular psoriasis. Pustules may vary in size and shape and, depending on the color of the exudate, may appear white, yellow, or greenish yellow. Can be follicular and non-follicular. Follicular pustules are conical, usually contain a hair in the center, and generally heal without scarring. Pustules are characteristic for rosacea, pustular psoriasis, Reiters disease, and some drug eruptions, especially those due to bromide or iodide. Vesicular lesions of some viral diseases (varicella, variola, vaccinia, herpes simplex, and herpes zoster), as well as the lesions of dermatophytosis, may become pustular. A Grams stain and culture of the exudate from pustules should always be performed.
Erosions An erosion is a moist, circumscribed, usually depressed lesion that results from loss of all or a portion of the viable epidermis. After the rupture of vesicles or bullae, the moist areas remaining at the base are called erosions. Extensive areas of denudation due to erosions may be seen in bullous diseases such as pemphigus. Unless they become secondarily infected, erosions usually do not scar. If inflammation extends into the papillary dermis, an ulcer is present and scarring results, as in vaccinia and variola, and less often in herpes zoster and varicella.
Ulcers An ulcer is a lesion in which there has been destruction of the epidermis and at least the upper (papillary) dermis involved. Ulcers are healing through scarring. Certain features that are helpful in determining the cause of ulcers and that must be considered in describing them include location, borders, base, discharge, and any associated topographic features of the lesion or surrounding skin such as nodules, excoriations, varicosities, hair distribution, presence or absence of sweating, and adjacent pulses. Stasis ulcers are accompanied by pigmentation and, occasionally, by edema or sclerosis. Ulceration occurs in granulomatous nodules of various types due to deep fungi, tuberculosis, syphilis, and yaws, as well as in a variety of parasitic and bacteriologic disorders. Nodules adjacent to ulcerations suggest granulomatous or neoplastic disease.
Scar A scar occurs wherever ulceration has taken place and reflects the pattern of healing in those areas. Scars may be hypertrophic or atrophic. They may be sclerotic, or hard, as a consequence of collagen proliferation. The scarred epidermis is thin, generally without normal skin lines and without appendages. A depressed scar may resemble the primary atrophy. Scars may occur in the course of acne, some porphyrias, herpes zoster, and varicella. Raynauds disease, syphilis, tuberculosis (especially on the face), leprosy, or carcinoma may produce mutilations, or a loss of tissue that alters major anatomic structures.
Scaling (desquamation) Abnormal shedding or accumulation of stratum corneum in perceptible flakes is called scaling. Under normal circumstances the epidermis is completely replaced every 27 days. The end product of this holocrine process of keratinization is the cornified cell of the outermost layer of the skin – the stratum corneum. The cornified cell is packed with fllamentous proteins, normally does not contain a nucleus and is usually lost imperceptible. When keratinocytes production occurs at an increased rate, as in psoriasis, immature keratinocytes that retain nuclei reach the skin surface – this is called parakeratosis. Parakeratotic cells may pile up and contribute to the formation of scales. In psoriasis, scales may appear in thin sheets or accumulate massively, suggesting the appearance of an oyster shell. Densely adherent scales that have a gritty feel like sandpaper are typically seen in solar keratosis. Fishlike scale occurs in a group of disorders known as ichthyoses, in some of which prolonged retention of the stratum corneum occurs even though it is produced at a normal rate. Scaling lesions also occur in dermatophyte infections, pityriasis rosea, secondary and tertiary syphilis.
Crusts (encrusted exudates) Crusts result when serum, blood, or purulent exudate dries on the skin surface, and are characteristic of pyogenic infections. Crusts may be thin, delicate, and friable, or thick and adherent. Crusts are yellow when formed from dried serum, green or yellow-green when formed from purulent exudate, or brown or dark red when formed from blood. Crusts may be present in acute eczematous dermatitis and impetigo (honey-colored, glistening crusts). When the exudate or crust involves the entire epidermis, the crusts may be thick and adherent: this condition is known as ecthyma. A scutula is a small, yellowish, cupshaped crust especially characteristic of superficial fungal infection of the scalp caused by Trichophyton schoenleinii.
Excoriations Excoriations are superficial excavations of epidermis that may be linear or punctate and result from scratching. They are findings in all types of pruritus and are concomitants of pruritic skin disease, such as atopic eczema, dermatitis herpetiformis, or infestations.
Fissures Fissures are linear cleavages or cracks in the skin and may be painful. They occur particularly in palmar/plantar psoriasis and in chronic eczematous dermatitis of the hands and feet, especially after therapy that has caused excessive drying of the skin. Fissures are frequently noted in perianal psoriasis or at the angles of the mouth (perleche). Perleche mat be caused by avitaminosis, moniliasis, ill-fitting dentures, or unknown factors.
Lichenification Repeated rubbing, especially in people with chronic eczema, leads to areas of lichenification. Proliferation of keratinocytes and stratum corneum, in combination with changes in the collagen of the underlying dermis, causes lichenified areas of skin to appear as thickened plaques with accentuated skin markings. The lesions may resemble tree bark. They are findings in atopic dermatitis, chronic eczema, neurodermitis, etc.