The Fundamentals of Dermatologic Diagnosis

The Fundamentals of Dermatologic Diagnosis

Mary E. Hurley, MDClinical Instructor, UTSW

Private Practice, Presbyterian Hospital Dallas

What is most difficult of all? It is what appears most simple:

to see with your eyes what lies in front of your eyes.

Goethe

General Observation

Start gathering data the moment you walk in the room

Ask yourself the following questions– Is the patient

awake, alert, and responsive? well appearing? acutely ill appearing? chronically ill appearing? in distress or uncomfortable?

uncomfortable child with atopic dermatitis

History and Review of Systems

Make sure you ask appropriate questions in the history and review of systems.

– What is the location of the problem? – How long have they had the problem? – Does is itch? – Is it painful? – What makes it better or worse? – What treatments have they tried? – Is the patient on any medicines? – Does the patient have a family history of skin disease or skin

cancer?

The Skin Exam

Perform a total body skin exam in a systematic and deliberate manner. – This includes the entire skin surface, the hair, the

nails, the conjunctiva, and the oral and genital mucosa.

– Ideally, the patient would remove undergarments and wear an examination gown only.

The Skin Exam

Be sure to examine the oral mucosa! Oral erosion in SLE.

The Skin Exam

Melanoma can appear anywhere. If you don’t look, you will miss it, and the patient may miss an opportunity for therapy.

The Skin Exam

Examination of the skin is an essential part of a thorough patient encounter.

Observation and palpation are the two most important aspects of the skin exam.

– Please seek to examine a patient’s entire skin surface. Patient wearing a gown Preserve modesty

– Good lighting is essential. Natural light is optimal.

The Skin Exam

Specific language used to describe the characteristics of skin lesions

Distribution Arrangement Type of lesion

– Primary lesion– Secondary lesion

Color Features based on touch/palpation

Distribution

Generalized vs localized Exposed vs non-exposed Sun-exposed vs non-sun-exposed Acral (head, neck and extremities) vs truncal Extensor (posterior arms, anterior legs) vs flexor (anterior arms, posterior legs) surfaces Bilateral vs unilateral Upper vs lower extremity Dermatomal (following the distribution of a spinal nerve root) Hair-bearing (non-glabrous) vs non-hair-bearing (glabrous) skin Follicular vs perifollicular vs non-follicular Seborrheic (areas with high concentrations of sebaceous glands: e.g. brows, nasolabial folds) Facial, periocular, perioral Intertriginous (areas where skin folds on itself) Mucous membrane Sites of pressure Sites of trauma (koebnerization) Palmo-plantar Periungual (around the fingernails)

Sun Exposed

malar rash of acute cutaneous lupus

symmetric and generalized

dermatomal following the distribution of a spinal nerve root

atopic dermatitis involving flexoral areas

nickel dermatitis from earring

Arrangement

Isolated Scattered Grouped

– Herpetiform (random grouping)– Zosteriform (grouping in dermatomes)

Circular– Annular (complete ring)– Arciform (incomplete ring)– Polycyclic (multiple rings)

Linear Angular Reticulated or mat-like

Grouped (herpetiform)

herpes simplex infection

Grouped (zosteriform)

herpes zoster

Annular (complete ring)

pustular psoriasissubacute cutaneous lupus

LinearPsoriasis

Type of lesion

Primary lesion Macule - Non-palpable lesion with distinct borders, less than 1 cm in diameter Patch - Non-palpable lesion with distinct borders, greater than 1 cm in diameter Papule – Palpable, solid lesion less than 1 cm in diameter Plaque – Palpable, solid lesion greater than 1 cm in diameter Nodule – Palpable, lesion more than 1 cm in diameter which is taller than it is wide Vesicle – Fluid-containing, superficial, thin-walled cavity less than 1 cm Bulla – Fluid-containing ,superficial, thin-walled cavity greater than 1 cm Erosion – A skin defect where there has been loss of the epidermis only Ulcer – A skin defect where there has been loss of the epidermis and dermis Pustule – Pus containing, superficial, thin-walled cavity Abscess – Thick-walled cavity containing pus

Macule: Non-palpable change in skin color with distinct borders

Macule: Non-palpable change in skin color with distinct borders

Patch: Non-palpable change in skin color with distinct borders

Papule: Palpable, solid lesion less than 1 cm in diameter



blue nevus

Plaque:Palpable, solid lesion greater than 1 cm in diameter


psoriasis


urticaria

Vesicle: Fluid-containing, superficial, thin-walled cavity less than 1 cm



varicella with vesicles and bullae

Nodule: Palpable, lesion more than 1 cm in diameter which is taller than it is wide


neurofibromatosis with multiple papules and nodules


Bulla: Fluid-containing ,superficial, thin-walled cavity greater than 1 cm

Bulla: Fluid-containing ,superficial, thin-walled cavity greater than 1 cm

bullous pemphigoid

Erosion: A skin defect where there has been loss of the epidermis only

Erosion: A skin defect where there has been loss of the epidermis only

toxic epidermal necrolysis

Ulcer: A skin defect where there has been loss of the epidermis and dermis

Ulcer: A skin defect where there has been loss of the epidermis and dermis

pyoderma gangrenosum

Pustule: Pus containing, superficial, thin-walled cavity

www.medstudents.com


Inflammatory acne


pustule over joint in disseminated gonococcemia

Abscess:Thick-walled cavity containing pus

Abscess:Thick-walled cavity containing pus

Secondary Lesions: changes in skin which are superimposed or are the consequence of the primary process

– Scale - desquamating layers of stratum corneum. – Crust- dried serum, blood or purulent exudate. Crusts are a sign of

pyogenic infection. – Lichenification - skin thickening that is the result of chronic rubbing

leading to accentuation of normal skin lines. – Atrophy- epidermal atrophy results from a decrease in the number of

epidermal cell layers. Dermal atrophy results from a decrease in the dermal connective tissue.

– Scar- a lesion formed as a result of dermal damage. – Excoriation - superficial excavations of the epidermis that result from

scratching. – Fissure - a linear painful crack in the skin.

Scale:desquamating layers of stratum corneum

Fungal infection

Crust:dried serum, blood or purulent exudate

Crusts are a sign of pyogenic infection

impetigo with honey colored crust

.

Atopic dermatitis with lichenification

Lichenification – skin thickening that is the result of chronic rubbing leading to accentuation of normal skin lines.

Atrophy

– Epidermal atrophy results from a decrease in the number of epidermal cell layers.

– Dermal atrophy results from a decrease in the dermal connective tissue.

Scar

Scar- a lesion formed as a result of dermal damage.

linear excoriations in a patient with atopic dermatitis

Excoriation:–superficial excavation of the epidermis that results from scratching

Color

Skin- or flesh-colored Hypopigmented vs hyperpigmented White Brown Grey Black Red Blue Violaceous Dark purple (purpura) Yellow Orange Green

Erythematous

Hyperpigmented

Melanoma with regression

Black

Brown

White

Red

Argyria

Blue-Gray

Violaceous skin lesions of dermatomyositis

Purpura

palpable purpura

The Skin Exam

Observe the patient’s skin color. – Substances contributing to the skin’s color include:

melanin (brown) and carotenoids (yellow) in the epidermis oxyhemoglobin (red, located in arterial plexus) and

reduced hemoglobin (bluish-red, located in the venous plexus) in the dermis

– increased pigmentation may suggest Addison’s disease or metastatic melanoma

– yellow color may suggest jaundice from liver disease– cyanosis or a bluish color to the lips may suggest hypoxia

The Skin Exam

yellow coloration of sclerae in patient with liver disease

The Skin Exam

Palpate and observe the patient’s skin for level of moisture, temperature, texture, mobility and turgor.

– dry, rough skin may suggest hypothyroidism– moist, warm skin may suggest an underlying febrile illness or

hyperthyroidism– excoriations may suggest a pruritic skin eruption such as

scabies or an underlying systemic disease such as lymphoma– tight, bound-down skin over the hands or face may suggest a

diagnosis of scleroderma

Features based on touch or palpation

Consistency– soft, doughy, rubbery, firm, hard

Dry vs wet Fixed vs mobile Presence or absence of tenderness Surface characteristics

– smooth, velvety, pebbled

The Skin Exam

Metastatic breast cancer must be PALPATED to be fully appreciated.

Nodule

Rubbery, Mobile, Non-tender

Melanoma metastases

Firm, Fixed, Nodules

sclerodactyly

Cellulitis

Erythematous, Tender, Warm to touch

Abscess

Tender, Fluctuant, Warm

Wet, Tender, Ulcerated

Dry

Consider the use of diagnostic aids

Magnify the lesions with a hand lens or using epiluminescence microscopy (using a hand lens with magnification and lighting built in to better visualize lesions).


Use a wood’s lamp (long wavelength ultraviolet light) to examine if a lesion is hypo or depigmented or to see if a fungal infection fluoresces.


Use diascopy (press a transparent, firm object such as a glass slide against a lesion) to determine if an erythematous lesion blanches. – If the lesion blanches or loses its erythematous

color, this suggests that the erythema is due to capillary dilation.

– If the lesion does not blanch or lose its red color, this suggests that the erythema is due to extravasation of blood (this can result from vasculitis or destruction of the vessel wall).


apple jelly color with diascopy of cutaneous sarcoid

References

Bickley LS, Hoekelman RA. Physical Examination: Approach and Overview, The General Survey, The Skin. In: Bickley LS, Hoekelman RA, editors. Bates Guide to Physical Examination and History Taking. Philadelphia: Lippincott Williams and Wilkins; 1999. p. 129-161.

Stewart MI, Bernhard JD, Cropley TG, Fitzpatrick TB. The Structure of Skins Lesions and Fundamentals of Diagnosis. In: Freedberg IM, Eisen AZ, Wolff K, et al, editors. Fitzpatrick’s Dermatology in General Medicine 6th Edition. New York: McGraw-Hill; 2003. p. 11-30.

Bolognia JL, Jorizzo JL, Rapini RP. Dermatology. Spain: Elsevier Limited; 2003.

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The Fundamentals of Dermatologic Diagnosis