Dermatology

Daniela V. P. Antelo, MD & Maria Cecilia A. Lopes, MD

Dermatologic Semiology



Introduction

Dermatologic diagnosis is based uppon systematic approach which includes history, physical examination and diagnostic tests.

There are some relevant aspects that must be asked in the history:

-age
-breed
-sex
-occupation (work environment)
-geographic location
-previous skin diseases
-associated symptoms (itching, pain,etc)
-therapy used and response
-exacerbation of the lesions by the sun or irritating substances exposure
-similar cases in family

In the physical examination, the appearance of the lesion is an important feature to be considered, that is why is necessary a careful approach and detailed examination. The exam must procede as follows:

- Identify the type of the lesion : ( described latter in the text)

primary

: macule, papule, plaque, wheal, cyst, nodule, tumor, vesicle, bulla and pustule.

secondary

: scale, crust, lichenification, scar, excoriation, fissure, ulceration, ulcer, erosion and atrophy.

vascular lesions

: purpura, petechiae, ecchymoses, telangiectasia.

- Caractherize the shape (anular, linear, serpiginous, flat-topped, dome-shapped,...) and arrangement of lesions (diffuse, herpetiform,...)

- Observe the distribution of lesions on the body ( localized, generalized,...)

Sometimes diagnostic tests are necessary to elicit diagnosis ( serologic tests, biopsies, culture plus antimicrobial sensitivy, dermatophy test media-ring worm, ...)

Primary skin lesions

Macule: flat and well-demarcated lesion of any size, caractherized by color change in contrast to the surrounding skin. It is generally caused by alteration of melanin pigment.
Eg.:
- ephelid or "freckle"
- vitiligo
- tinea versicolor

Papule: elevated, solid and circumscibed lesion, usually 1 cm or less in diameter.
Eg.:
- hyperkeratotic: warts, seborrheic keratoses
- purple: drug eruptions, Kaposi's sarcoma
- red: miliaria, scabies

Plaque: elevated, flat-topped, firm and superficial lesion, usually greater than 1 cm in diameter; may be coalesced papules.
Eg.:
- psoriasis
- eczematous dermatitis

Wheal: transient, solid, itchy, raised area of cutaneous edema with irregular shape, different diameter and variable blanching and erythema.
Eg.:
- urticaria
- insect bites

Nodule: Raised, circumscribed, firm lesion; variable diameter (usually 1-3 cm); deeper in dermis than papule. It can be seen in gross inspection or only on palpation.
Ex.:
- lipoma
- erythema nodosum

Vesicle: elevated, thin-walled lesion; filled with serous (clear) fluid, less than 1 cm in diameter.
Ex.:
- Herpes simples
- Varicella
- Herpes Zoster
- Dyshidrose
- Dermatitis herpetiformis
- Miliaria

Bulla: elevated lesion filled with clear fluid, greater than 1 cm in diameter.
Eg.:
- pemphigus
- pemphigoid
- drug eruptions
- Stevens-Johnson syndrome
- blister

Cyst: elevated and encapsulated lesion filled with semisolid or liquid content.

Eg:
- sebaceous cyst
- cystic acne

Pustule: elevated lesion filled with purulent fuid. The presence of the pustule does not necessarily signify the existence of an infection.
Eg.:
- acne vulgaris
- impetigo
- variolla
- foliculitis
- candidiasis

Secondary skin lesions:

Scale: flaky exfoliation; a plate like excrescence of varied size, usually composed of accumulated stratum corneum.
Eg.:
- psoriasis
- dermatitis
- tinea versicolor
- pityriasis rosea
- intertrigo

Crust (Scab): a solid consolidation of dried serum, blood, plus
Eg.:
- eczema
- scab on abrasion

Lichenification: Thickened and rough epidermis with accentuation of skin markings.
Eg.:
- chronic contact eczema

Scar: fibrous tissue secondary to dermis injury. It may be pink, red or white; atrophic or hypertrophic (keloid)
Eg.:
- healed wound

Excoriation: loss of epidermis caused by a traumatic lesion causing a linear area.
Eg.:
- deep scratch
- abrasion

Fissure: a linear and small split or crack in the epidermis and dermis.
Eg.:
- cheilosis

Erosion: discontinuity of the skin with loss of part or all epidermis, usually follows rupture of vesicle or bulla.
Eg.:
- varicella (following rupture)
- variolla (following rupture)

Ulceration: discontinuity of the skin with loss of epidermis; and sometimes hipodermis. Usually heals with scaring.
Eg.:
- decubitis
- herpes simplex
- syphilis (chancre)

Ulcers: ulceration without tendency of healing (scaring).
Eg.:
- stasis ulcers

Atrophy: reduction of skin thickening ocurring at any skin layer.
Eg.:
- striae
- aged skin

Vascular Lesions

Purpura: red-purple non-blanching coloured lesion due to extravation of blood into the tissue.
Eg.:
- Henoch-Schoenlein purpura
- thrombocytopenic purpura
- infection

Petechiae: is a punctiform purpura.
Eg.:
- vasculitis
- infection

Ecchymoses: purpura greater than 1 cm in diameter.
Eg.:
- trauma
- vasculitis

Telangiectasia: permanent dilated superficial blood vessels.
Eg.:
- telangectasia in liver disease
- telangectasia in pregnancy
- telangectasia in breast cancer
- telangectasia in lupus erythematosus, sistemic or discoid.

Special thanks to Prof. Celso Tavares Sodré and to Prof. Sueli Carneiro

If you have suggestions or comments send an e-mail to Daniela V. P. Antelo & Maria Cecilia A. Lopes

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