1. Skin Lesions and Diagnosis
James H Herndon MD
Clinical Professor, Dermatology
UT Southwestern Medical Center
2. Skin Lesions and Diagnosis
• Recognition of the significant can be life-and
health-saving (melanoma, RMSF,
vasculitis)
• Failure to recognize normal/inconsequential
can also cause harm (the black seborrheic
keratosis, pigmentary purpura of the lower
legs, physiologic variations in genital areas)
3. Skin Lesions and Diagnosis
• Skin acts as window in several ways. Two
examples:
– Point mutations may cause skin and internal change.
• Birt-Hogg-Dube Syndrome causes cutaneous
fibrofolliculomas, renal tumors, and spontaneous
pneumothorax by affecting the folliculin gene.
– Hormonal overdose causes skin and internal change.
• PCOS causes elevated androgens -> acne, hirsutism and
also hyperinsulinemia -> acanthosis nigricans and diabetes
4. Skin Lesions and Diagnosis
• How to bring order to confusion:
– What component is mainly affected? (dermis,
epidermis, subcutaneous fat, blood vessels)
– What is the primary change and what is secondary?
– Next assess the lesions by type, shape, arrangement,
and distribution.
– Finally, how did the changes evolve over time?
5. Skin Lesions and Diagnosis
• How to bring order from confusion, continued.
– History should contain: exact description of onset,
first lesions if any, details of development.
– Prior treatment, of home or physician source, and the
diagnosis(es) based on.
– Other drugs, herbal remedies, ethnic medications.
– Effect of sunlight, season, contact with immediate
environment (plants, animals, chemicals, metals).
– Role of physiologic changes (menses, pregnancy).
6. Skin Lesions and Diagnosis
• Why do experienced clinicians often view the
rash before taking a history?
– Visual diagnosis may be sharper without
preconceived ideas.
– Some lesions and patterns are so distinctive that
history is needed only as confirmation.
– In other cases the rash guides and interacts with the
history, allowing one to diagnose more efficiently.
But in the usual multi-problem medical patient the general medical history is essential:
1. Identifying data: age, sex, race, occupation.
2. History of present illness: onset, evolution, precipitating and relieving factors.
3. Past medical history: illnesses, operations, hospitalizations, pregnancies, allergies (especially drug), hazardous exposures, habits, and diet. In the dermatologic history atopic disorders - both respiratory and cutanewous - are of prime importance.
4. Present and recent medications.
5. Social history: residence, travel, employment, hobbies, marital and emotional status, pets.
6. Sexual history: risk factors for sexually transmitted diseases.
7. Family history: skin diseases, allergies, atopic disorders, as well as diseases of each of the other systems. A patient presenting with pruritus commands us to determine if anyone at home or with whom the patient is intimate is itching
.8. System review:constitutional symptoms (fever, sweats, chills, headache, nausea, etc, the “acute illness syndrome”) vs the “chronic illness syndrome” of fatigue, anorexia, weight loss, etc. Check with care systems often involved with skin disorders: eyes, respiratory, vessels, gi, gu, endocirne, muscles, nodes.
A macule is a circumscribed, flat lesion by that it differs from surrounding skin only because of its color. Macules may have any size or shape. They may be hyperpigmented, hypopigmented, erythematous due to vascular or capillary dilatation, or purpuric. Macules with a very fine scale at their surfaces are called maculosquamous, as in the tinea versicolor.
The clinical photo shows an eruption consisting of multiple, well-defined red macules of varying size which blanch on pressure with a glass slide (diascopy), and are thus due to the inflammatory vasodilatation. It in this case the patient has a drug reaction due to phenolphthalein.
The papule is a small, solid, elevated lesion. By definition, papules are smaller than one cm in diameter, and the major portion of a papule projects upward, above the plane of the skin. Papules may result, for example, from metabolic deposits in the dermis (A), from localized cellular infiltrates (B), or from localized hyperplasia of cellular elements in the dermis or epidermis (C). Papules with scaling are called papulosquamous lesions and occur in, for example, psoriasis.
The clinical photos show first, a patient with two solid, well-defined and dome-shaped papules of firm consistency and brownish color, which are likely to represent dermal melanocytic nevi. In the lower photo one sees multiple, well-defined, and coalescing papules of varying size. Though not well shown here, these had violaceous coloring, glistening surfaces, and flattened tops characteristic of lichen planus.
A plaque is a mesa-like elevation occupying a relatively large surface area in comparison with its height above the skin surface. Well-defined, reddish, scaling plaques that coalesce to cover large areas of the posterior thigh are seen in the upper clinical photograph. A modest amount of regression can be appreciated in the central areas of some of the plaques in the upper portion of the photo. All of these features are characteristic of psoriasis.
Lichenification represents a thickening of the skin together with accentuation of skin markings. The process results from repeated rubbing and frequently develops in persons with atopic eczema, but can occur in the other forms of eczematous dermatitis or other conditions associated with chronic itching. This process is still in an early stage in the lower clinical photograph, taken of a patient with nummular (coin-sized or coin-shaped from the Latin nummus = coin) eczema.
A nodule is a palpable, solid, round lesion. It differs from a papule mainly by depth of involvement and/or substantive palpability rather than by diameter. A nodule may consist of cells derived from the epidermis, from an epidermal appendage, from a neoplasm, or from a metabolic deposit. A and B illustrate two possibilities for the origin of nodules.
The photograph shows multiple nodules of varying sizes shown in a patient with metastatic melanoma.
A wheal is a rounded or flat-topped elevated lesion that characteristically lasts only a few hours. Wheals may appear as tiny papules 3 to 4 mm in diameter, as in cholinergic urticaria shown in the middle photograph. In other patients they may be large, coalescing plaques, as in allergic reactions to medications shown in the far right photograph of an urticarial reaction to penicillin.
A vesicle is a circumscribed and elevated lesion that contains fluid. The drawing shows (A) subcorneal vesicles resulting from cleavage just below the stratum corneum, and (B) spongiotic vesicles resulting from intercellular edema. A bulla is a vesicle larger than 0.5 cm.
The clinical photograph shows multiple translucent subcorneal vesicles which are fragile, collapse easily, and lead to crusting. These lesions represent impetigo due either to streptococci or staphylococci, either of which can synthesize a specific epidermolytic toxin capable of inactivating an important adhesive protein, desmoglein 3, found mainly in the upper epidermis. .
(A) Acantholytic vesicles result from cleavage within the epidermis due to loss of intercellular attachments. (B)Ballooning degeneration of epidermal cells leads to the formation of vesicles in many viral infections such as varicella-zoster shown in the photograph. The characteristic feature of centrally-located umbilication is seen in many of these vesicles, which appear in crops and in characteristic groupings.
Subepidermal vesicles, as shown in the drawing, occur following pathologic change in the region of the dermal-epidermal junction. This important area sustains damage with bullous erythema multiforme, porphyria cutanea tarda, epidermolysis bullosa, dermatitis herpetiformis, and bullous pemphigoid. The clinical photograph illustrates the latter condition. Some of the bullae arise on normal and some on erythematous skin. Most of them are tense and filled with serious or hemorrhagic fluid. Some have collapsed and become crusted.
An erosion is a moist, circumscribed, usually depressed lesion resulting from loss of all or a portion of the viable epidermis. Erosions remain after the roofs of vesicles and bullae become detached and usually heal without scarring. The clinical photograph represents an erosion from herpes simplex infection.
A pustule, shown in the drawing on the left, is a circumscribed, raised lesion-usually a papule-that contains purulent exudate. Primary, non-follicular pustules occur in pustular psoriasis, shown on the right. These are very superficial, subcorneal pustules which coalesce, occasionally forming lakes of pus. .
A cyst is a sac that contains liquid or semisolid material such as fluid, cells, and cell products. A spherical or oval nodule or papule may clinically be suspected of being a cyst if it is resilient on palpation. The common cysts, shown in the drawing at left, include epidermal cysts (A), lined with squamous epithelium which produce keratinous material. Cysts of hair follicle origin are lined with multilayered epithelium that does not mature through a granular layer. These are called pilar cysts (B).The bluish resilient cyst shown on the right photograph represents a cystic adnexal tumor, in this case a cystic hidradenoma, which is filled with a mucus-like material.
Atrophy of the skin may be limited to the epidermis or the dermis or may simultaneously occur in both. As shown in the drawing on the left, epidermal atrophy (B) displays a thin, almost transparent epidermis. A- trophic epidermis may or may not retain the normal skin lines. Dermal atrophy (A) results from a decrease in the papillary or reticular dermal connective tissue and produces a depression in the skin.
Atrophy of the subcutaneous tissue may also lead to depressions in the surface of the skin. The clinical photograph shows marked dermal and epidermal atrophy with loss of normal skin texture, thinning, and wrinkling.
An ulcer is a depressed lesion in which the epidermis and at least the upper, papillary dermis have been destroyed. Ulcers always heal with scarring for this reason. The clinical photograph shows a sharply demarcated, punched-out ulcer following a severe recurrence of herpes simplex of the buttock area.
A scar occurs whenever ulceration has taken place. It develops so as to reflect the pattern of healing characteristic of that area of skin. A scar may be hypertrophic (A) or atrophic (B).
The photograph shows a typical clinical example of hypertrophic scar. (A keloidal scar differs from a hypertrophic one in exhibiting a pattern of growth that outstrips the boundaries of the original ulcer or wound).
Abnormal shedding or accumulation of stratum corneum in the form of perceptible flakes is called scaling and is shown in the drawing. Parakeratotic scale ( in which the nuclei are retained) is seen in association with psoriasis and psoriasiform dermatitis(A). Densely adherent scale with a sandpaper-like surface is seen covering actinic keratoses (B).
A typical silvery psoriatic scaling is shown in the photograph. Occasionally scales in this disease adhere tightly to the underlying epidermis, building up to form an asbestos-like layer that obscures the underlying cutaneous details.
Crusts or crusted exudates result when serum, blood, or purulent exudate dries on the skin surface. Crusts may be thin, delicate, and friable(A), as in some cases of impetigo as shown in the photograph, or thick and adherent (B) as shown in the drawing.
Everyone is familiar with the linear marks on the skin surface left by poison ivy resin, but the dermis can also be the primary target of linear processes such as morphea (en coup de sabre = the cut of the saber). The child on the left has such a lesion.
Annular, arciform, and polycyclic lesions formed in many cutaneous conditions (urticaria, erythema annulare, granuloma annulare, etc.). The clinical photo on the right shows a patient with erythema annulare centrifugum who has many arcs and circles as part of this condition.
Iris-type lesions are those which a clear in the center and, usually circular or oval, possess accentuated borders. Granuloma annulare, erythema multiforme, and many other immunologically mediated conditions paint the body in this way with the skin as their canvas.
The grouped (or herpetiform) lesions of herpes viruses depend on an anatomic arrangement. Here the cutaneous nerves arborize beneath the surface, reaching their nerve endings in a tightly grouped pattern. Viral agents which reach the skin along these nerves tend to assume the same pattern.
The grouped (or herpetiform) lesions of herpes viruses depend on an anatomic arrangement. Here the cutaneous nerves arborize beneath the surface, reaching their nerve endings in a tightly grouped pattern. Viral agents which reach the skin along these nerves tend to assume the same pattern.
A zosteriform pattern depends on the macro, dermatomal nerve distribution, following the layout of spinal and cranial nerves. Vitiligo and more rarely type I neurofibromatosus may follow this pattern.
