Objective Symptoms

According to the nature of the pathologic process the lesions assume more or less distinct characteristics. They may be uniform or diverse in size, shape, and color and may be in different stages of evolution or of involution. The original lesion is known as the primary or elementary lesion. It may continue to full development, or as a result of regression or of trauma, or other extraneous factors may undergo modification, and in this altered form is known as a secondary lesion. There may be no primary lesion and just secondary lesions, i.e., in pruritus with excoriations.

Primary or Elementary Lesions

       These are of the following form-smacules, papules, nodules, tubercles, tumors, wheals, vesicles, bullae, and pustules. Each will be considered separately.

 Macules (Maculae, Spots).

      Macules are variously sized circumscribed alterations in the color of the skin, without elevation or depression. They are usually rounded, but may be oval or irregular in shape, and may be distinct in outline or fade into the surrounding area.

     Macules may constitute the whole of the eruption or a part, or may be merely an early phase or an associated symptom. Occasionally the spots tend to become slightly raised, when they are designated maculopapules.

Papules (Pimples or Papulae). 

       These are circumscribed, solid elevations with no visible fluid, varying in size from a pinhead to a pea. They may be acuminate, rounded, conical, flat, or umbilicated, and whitish (as in milium), red ( as in eczema), yellowish ( as in xanthorna), yellowish-brown ( as in lupus vulgaris ) or blackish ( as in melanoma).

       Papules may be seated in the corium, around sebaceous glands, at the orifices of the sweat ducts, or at the hair follicles. They may be of soft or firm consistency and the surface may be smooth, or rough, and capped by scales when they are known as squamous papules. When situated at the hair follicles the lesion may have a horny spine ( as in keratosis pilaris).

      Some papules are discrete and irregularly distributed as in papular urticaria, while others are in groups as in lichen scrofulosorum. Some persist as papules, whereas those of the inflammatory type may progress to vesicles and even to pustules, or may form ulcers before regression takes place.

      

      Nodules or tubercles are a form of papule, being larger solid lesions, but generally of a persistent character, perhaps midway between a papule and a small tumor. They differ from papules in being in close association with the corium or subcutaneous tissue, and in projecting notably both upward and downward.

Tumors. 

      

     These are soft or firm, freely movable, or fixed masses, of various sizes and shapes. They may be elevated, or deep seated and, in some instances, are pedunculated (fibromas). Tumors have a tendency to be rounded, and their consistency depends upon the constituents of the lesion, which may be either inflammatory or neoplastic. Some tumors remain stationary indefinitely, while others increase in size, or break down as a result of infection and necrosis, and disappear.

Wheals (Urticae, Pomphi).
 
     Wheals are evanescent, edematous, flat elevations of various sizes. They are usually oval, and whitish or pinkish. and are surrounded by a pink areola. They may be discrete, or coalesce to form solid plaques; and they may be round, irregular, or linear when due to scratching. These lesions develop rapidly in a few seconds, and disappear more slowly. Itching and tingling are almost always present. 

Vesicles (Small Blisters or Vesiculae). 

     Vesicles are circumscribed, epidermal elevations of pinhead to pea size, and contain a clear fluid, They may be pale, or yellowish from seropurulent matter, or reddish from serum mixed with blood, and occasionally have deep reddish areolae. The apex may be rounded, acuminate, umbilicated, or torn. Vesicles may be discrete, irregularly scattered or arranged in groups or rows. They may arise directly or from a macule or papule, and generally lose their identity in a short time, breaking spontaneously, or developing into blebs through coalescence or enlargement, or into pustules. When the contents are of a seropurulent character the lesions are known as vesicopustules. Vesicles consist of either a single cavity (unilocular ) or of several compartments (rnultilocular), containing fluid.

Bullae (Blebs, Blisters).

     These are rounded or irregularly shaped blisters containing serous or seropurulent fluid. They differ from vesicles only in size, being larger than a pea. They are usually single chambered and located superficially in the epidermis, so that their walls are thin and subject to rupture spontaneously or from some slight injury. After rupture, remnants of the thin walls may persist, and together with the exudate may dry to form a thin crust, or the broken bleb may leave a raw and moist base, which may be covered with seropurulent or purulent slough, and more rarely with irregular vegetations (as in pemphigus vegetans). They may be multilocular. When the blebs are deeply situated, ulceration and scarring often result. Bullae may be tense or flaccid. In pemphigus and some other bullous diseases there is sometimes a lack of cohesion between the epidermis and the derma so that the epidermis can be easily rubbed off, leaving a raw moist abrasion (Nikolsky's sign). Hemorrhagic bullae are common in pemphigus, zoster, leukemia, and in lichen sclerosus et atrophicus. The cellular contents of bullae may be diagnostic in pemphigus, zoster, and in leukemia.

Pustules (Pustulae). 

     These are small elevations of the skin containing pus. They are similar to vesicles in shape, and may also have an inflammatory areola, and be unilocular or multilocular. They are usually whitish or yellowish, but may be reddish if they contain blood with the pus. They may originate as pustules, or may develop from papules or vesicles, passing through transitory early stages when they are known as papulo- or vesicopustules.