Are the Lesions Solid or Fluid Filled?
In simple terms, are blisters present or not? Recognition of large, intact blisters is easy, but identification of fluid-filled lesions is problematic in two other situations. First, very small vesicles, such as those occurring on the palms and soles in dyshidrosis, are often misidentified because of the their pinhead size and thick roofs. Second, the roofs of blisters are fragile, and by the time the patient is examined, the roof may be destroyed, leaving only a moist red erosion.
Erosions are encountered in only two settings: the blistering diseases (groups 1 and 2) and the eczematous diseases (group 10). Association of erosions with the diseases of groups 1 or 2 is possible if there is a clear-cut history of a preceding blister, there are adjacent intact blisters, or the erosion is round and a peripheral collarette of remaining roof fragments can be identified. On the other hand, assignment of the erosions to group 10 is appropriate if the erosions lack a collarette of roof fragments and if their shape is linear or angular. (Ulcers, as opposed to erosions, generally arise because of vascular compromise; they are considered with the vascular diseases, group 8.) The presence of even a few blisters (the appearance of the remaining eruption not withstanding) is sufficient to identify the disease as a member of either group 1 or group 2. The amount of inflammation at the base of blistering lesions is highly variable. In some situations the blisters arise from normal-appearing skin, whereas in others the blister is situated on top of a red lesion. Regardless of the ratio between inflammation and vesiculation, the presence of any blisters whatsoever requires assignment to group 1 or group 2.
If in doubt about the vesicular nature of a lesion, pierce the roof with a needle or blade. If fluid runs out and the lesion collapses, the lesion is clearly a blister. On the other hand, if only a small drop of fluid forms and the lesion remains otherwise unaltered, you may be dealing with an edematous papule such as an insect bite or urticarial wheal.
Are the Nonblistering Lesions Red or Some Other Color?
The remainder of the algorithm is devoted to nonblistering diseases. This usually does not cause any difficulty in interpretation, though the clinician should remember that erosions may be derived either from blistering diseases or from excoriation and eczematous disease. Also, ulcers (as opposed to erosions) are not derived from blisters and for the most part are categorized with the vascular diseases (group 8).
Determination of color is easy except for two circumstances.
First, red hues are hard to detect against the brown pigmentation of Latino and Afro-American patients. If in doubt when examining a dark-skinned patient, ask for his or her help with color interpretation.
Second, the presence of copious scale or crust may obscure the underlying lesional color. For purposes of this algorithm, scale and crust are ignored when lesion color is being assessed. Specifically, in the situation where the lesion appears to be composed almost entirely of keratin (scale) and there is no other apparent color (warts and actinic keratoses, for instance), the lesion is automatically assigned to the skin-colored lesions (group 3).
Sometimes, scale can also partially mask the underlying red color of lesions from groups 9 and 10. In this situation, a careful look at the periphery of the lesion, or the scraping of a bit of scale from the center of the lesion, generally provides sufficient color for accurate assignment. Finally, the yellow color of crust might cause erroneous assignment to the yellow lesions (group 6). This error is easily avoided if the clinician remembers that crust is to be ignored when determining color and, further, that all lesions classified in group 6 happen to be smooth surfaced.
Which Color, Other Than Red, Are the Lesions?
Skin-Colored Lesions. Determination that a lesion is”skin colored” depends on the degree to which the lesional color matches the hue of the patient’s normal skin. Thus, in a darkly pigmented person a skin-colored lesion may be brown, whereas in a lightly pigmented person a skin-colored lesion may appear white. Skin-colored lesions are subdivided into those that are rough surfaced (keratotic) and those that are smooth surfaced.
White Lesions. The term “white” as used in the context of the algorithm indicates that the lesions are lighter in color than the patient’s normal skin. The actual degree of whiteness is determined by the amount of melanin, if any, that is left in the lesions. White lesions are easy to recognize in all but the most lightly pigmented individuals. In this situation, examination in a darkened room, using a Wood’s lamp, may be of help, since the ultraviolet light increases the degree of color contrast between lesional and normal skin. The white lesions are subdivided into those that are papular and those that consist of patches and plaques.
Brown, Blue, and Black Lesions. To be assigned to this group, a lesion must be darker than the surrounding normal skin. The absolute color of the lesions classified in this group varies appreciably. The hue may be as light as the tan color of freckles or as dark as the black color of some seborrheic keratoses and melanomas. Remember that in a dark-skinned patient the “background” pigmentation can, and often does, obscure red hues. If you are inexperienced with examination of Afro-Americans and Latinos, ask the patient for help with color interpretation. For practical purposes, all (except seborrheic keratoses) of the brown, blue, and black lesions in group 5 are smooth surfaced. For this reason, the presence of scale on dark lesions should alert you to the likelihood that you are dealing with what in reality may be a red lesion. The brown-black lesions are subdivided on the basis of lesional diameter.
Yellow Lesions. The yellow lesions are easy to recognize except in some darkly pigmented persons where the yellow color appears somewhat beige. All of the yellow lesions categorized in group 6 are smooth surfaced. Crust accounts for the yellow color in rough-surfaced yellow lesions, and as indicated above, the color of crust must be disregarded in such circumstances. The yellow lesions are subdivided on the basis of elevation.
Are the Red Lesions Scaling or Nonscaling?
The last four groups in the algorithm consist of red lesions. They are separated into two subgroups based on the presence or absence of scale. Assignment of lesions to one or the other of these subgroups can be difficult for two reasons. First, the clinician must be able to recognize all three types of scale. The psoriatic-type scale is not easily missed because the flakes are white, large, and plentiful. On the other hand, the pityriasis-type scale is easily overlooked, since there is little roughness on palpation and the small size of the flakes obscures their white color until the lesion is scraped. The lichen-type scale may also be missed, since there is little or no white color even with scraping. The clinician can, however, appreciate palpable roughness and a distinctive shininess. A more complete description of the types of scale can be found .
Second, in some situations, scale, which should be present is inapparent because of actions carried out by the patient. Washing followed by brisk towel drying just prior to examination will temporarily remove scale. Moreover, application of lubricant obscures both the visualization and the calpability of scale. Finally, any previous treatment, even if it has been otherwise ineffective, often decreases the amount of scale formation to an inapparent level.
For all of the above reasons, the clinician should always palpate for roughness, scrape for white powder, look for shininess, and query the patient before assuming that no scale is present. Finally, remember that for a lesion to be considered scaling, it must demonstrate more scale than the surrounding skin. Dryness and mild chapping of the skin as a result of aging, sun damage, and excessive bathing is commonly encountered. This “background noise” must be subtracted before making any decision regarding the presence of scale.
Are the Red Lesions Monomorphic or Polymorphic?
Separation of group 7 (the red macules, papules, and nodules) from group 8 (the vascular reactions) can be difficult. The fIrst criterion to be applied requires that the various lesions making up the eruption be compared with one another. In a monomorphic eruption, individual lesions tend to be small and round, and there is a consistency in size and shape among all of the lesions. Thus, each of the lesions looks much like its neighbor. Moreover, individual lesions tend to remain fairly discrete even when they are closely set. On the other hand, in a polymorphic eruption, there is variability in size and/or shape from one lesion to another, and often, when lesions are closely set, they assume confluence to form a larger lesion with a serpiginous (gyrate) or ring-like border. The diseases in group 7 (the red macules, papules, and nodules) have lesions that are generally monomorphic, whereas the diseases of group 8 (the vascular reactions) are more polymorphic in appearance. Several other features can be used for guidelines. First, solitary lesions are, by definition, monomorphic and are thus generally assigned to group 7. Second, lesions in group 7, when elevated, tend to be hemispherical in cross section, whereas lesions in group 8, when elevated, tend to be flat topped. Finally, all purpuric lesions, regardless of size or shape, are found in group 8.
The diseases of group 7 are subdivided on the basis of lesion size, the diseases of group 8 are subdivided on the basis of blanch ability.
Tags:blistering diseases, dyshidrosis, keratotic, Lesions, macules, nonblistering lesions, papules, red lesions Skin Colored lesions
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