CHAPTER 29 PODIAfRIC DERMATOLOGY A Review
William D. Fisbco, DPM
Skin disorders make up a significant pafi of a busy of the integument. This is not meant to be an all- podiatric practice. Because much of our time in inclusive text, Lrut rather a focused presentation of practice is based on orthopedic-related pathologies, common podiatric-related dermatoses. skin disorders can pose a challenge for the clinician Description of skin lesions can be difficult if to diagnose and treat accordingly. The purpose of one does not use the proper terminology. Table 1 this article is to serve as a review and to provide a lists definitions of skin lesions. Moreover, skin practical approach to recognizing common disorders lesions can be grouped into classes based upon
Table I
DEFINITIONS OF SKIN LESIONS
Macule Flat lesion <1 cm Patch Large macule (>1 cm) Papule Elevated flat lesion (<0.5 cm) Nodule Elevated solid lesion (>0.5 cm) Plaque Elevated area of skin of >2 cm in diameter, a disc shaped lesion, formed by extension or coalescence of papules or nodules. Vesicle Fluid filled blister (<0.5 cm) Bu1la Larger blister (>0.5 cm) Pustule Collection of free pus Abscess Localized collection of pus in a cavity (>1 cm) Petechia Pinhead size extravasation of blood into skin Ecchymosis Larger extravasation of blood into skin Purpura Blood in skin up to 2 mm in diameter, may be palpable Hematoma Large purpura \X/heal Accumulation of dermal edema Angioedema Diffuse edema of deep dermis extending to subcutaneous tissue Comedo (comedones) Plug of keratin and sebum wedged in a dilated pilosebaceous orifice Burrow Small tunnel in the skin that houses scabtes Telangiectasia Visible clilatation of small clltaneous blood vessels Poikiloderma Combination of atrophy, reticulate hyperpigmentation and telangiectasia Sclerosis Induration of the subcutaneous tissues Gangrene Death of tissue, usually due to loss of blood supply Scale Flake from the horny layer Crust Dried serum, exudate or tissue fluid Ulcer Vhole of the epidermis and part of dermis lost Excoriation Linear erosion or ulcer produced by scratching Lichenification Chronic thickening of the epidermis with prominence of the normal skin markings. Erosion Partial loss of the epidermis Fissure Slit in the skin Sinus Channel that permits escape of pus or fluid Scar Result of healing, normai structure replaced by fibrous tissue Atrophy Thinning of skin due to diminution of the epidermis, dermis or subcutaneous fat Stria Linear, atrophic, pink or white lesions due to changes in connective tissue T50 CHAPTER 29 their morphology and color. \n/hen classifying not it has scale). Table 2 lists comlnon primary and lesions based Lipon morphology, Iocation, and secondary lesions. characteristics, one can quickly obtain a differential Not all scaling rashes of the foot are tinea cliagnosis. Symmetrical rashes generally suggest pedis. A simple and straight-for-ward way to rule some sort of endogenous process, for example ollt mycotic infection is to obtain a skin scraping psoriasis or atopic eczema. and send it for a KOH preparation or PAS stain. History taking is important. One should ask Rather than make a glress as to whether a scaling about timing and duration of the rash, details of the rash is tinea pedis versus eczema, obtain the rash spreading, evolution of rash and original proper diagnosis and treat accordingly. Table 3 morphology (i.e., blisters), symptoms such as itch, includes a differential diagnosis of lesions that have pain, burning sensation, numbness, precipitating scale. Table ,i includes a list of dermatoses that pre- and relieving factors such as climate, sunlight, and sent with lichenification. prior treatment (over-the-counter medications such Nfhen it comes to thick, discolored toenails as antifungals, antihistamines, and cortisone one has to think twice about onyhcomycosis. How creams). Also, it is inportant to assess for current often do you send a nail specimen that clinically skin disorders located elsewhere on the body, or presents as onychomycosis and the pathology history of skin disorders as a child such as atopic report says "no fungal elements seen?" \7e have all eczema. Social history such as work type and been taught that it is difficult to grow fungus in the traveling can be helpful as well. lab or that it is difficult to get a good sample. It is Examination of dermatoses should be based my belief that many of the presumed fungal nails upon morphology, color, location, and secondary are not primary fr-rngal infections. We all have a lesions (crusting, lichenification, and u,,hether or story about a patient that completed oral antifungal
Table 2 Table 3 Primary skin lesions Macule LESIONS THAT TIAVE SCALE Papurle Seborrheic keratosis Noclule Stucco keratosis Tumor Pityriasis alba Plaque Tinea pedis Vesicle Pityriasis rosea Bu11ae Psoriasis Pustule Lichen planus Wheal Pityriasis rubra pilaris Burrow- Secondary syphilis Telangiectasia Seborrheic dermatitis Secondary Skin Lesions Cutaneous drug reaction Scale Crust Atrophy Table 4 Lichenification Erosion Excoriation LICHENIFIED LESIONS Fissure Atopic dermatitis Ulceration Neurodermatitis Scar Lichen simplex chronicus Eschar Chronic contacr dermatitis Keloids Petechiae, Purpura, and Ecchymosis CHAPTER 29 t5t therapy with terbinafine or itraconazole and did for fungus, then one has to consider other treat- not have any improvement. That patient may have ment options. In addition, who says there can not done a second course of therapy that failed as well. be concomitant fungal infection with non-mycotic $i/as it drug failure or was it due to treating the diseases of the nails such as naii root disease? wrong disease? Non-mycotic diseases of the nail The most comrnon skin disorders affecting the (nai1 root trauma, biomechanical microtrauma, lower exlremrry include fungal infections, eczematous peripheral arteriaT disease, systemic diseases such conditions, psoriasis, and cutaneous manifestation of as psoriasis, and diabetes) are probably more com- systemic disease (i.e., diabetes related dermopathy, mon that we think. If the nail specimen is negative granuloma annulare, and necrobiosis lipoidica diabeticorum). Table 5 lists common cutaneolrs manifestations of internal disease. Thble 5 Less common skin disorders include cuta- neous malignancies such as basal cell carcinoma, LOWER EXTREMITY-REIAIED squamous cell carcinoma, and malignant melanoma. Certainly any suspicious looking lesion CTIIANEOUS MANIFESTATIONS whether pigmented or not should be biopsied. OF INTERNAL DISEASE The term eczema can be confusing to define or to explain to patients. Eczema in simple terms Disease Manifestation describes an inflammatory skin eruption. In the ini- Diabetes mellitus Necrobiosis lipoidica tial stages of the disease process, common clinical diabeticorum findings include erythema, papulo-vesicular Diabetic dermopathy lesions, weeping, and crusting. Later stages include Bullous diabeticorum red-purple color with scale, iichenification, and Neurotrophic rrlcerat ions possibly pigmented skin. Epithelial disruption and Granuloma annulare non-sharp margination are its characteristics. mp
Table 6
ECZEMA
Stage Morphology Symptoms Examples of Lesions Acute vesicles, blisters, intense itch, acute contact dermatitis, acute intense red stinging, burning nummular eczema, stasis clermatitis, pomphollx Subacute red, scale, slight to moderate ontact allergy, irritation, atopic fissuring, parched itch, stinging, dermatitis, stasis dermatltis, nummular appearance, scalded burning eczema, asteatotic eczema appeafance Chronic thickened skin, moderate to atopic dermatitis, lichen simPlex lichenifiecl intense itch chronicus, hyperkeratotic eczema excoriation, fissuring 152 CHAPTER 29
The most colrlnon dermatoses of the geo- Biopsies are encouraged for any lesion which graphic region of the foot include tinea pedis, is not easily identified as a benign process (i.e., eczema, xerosis, and contact dermatitis. In the lower dermatofibroma). Dermatologists biopsy just about 1eg, the most common dermatoses include xerosis, eveq,thing, so why should we be any different? It stasis dermatitis, and lichen simplex. does not take much time to get a biopsy, causes For treatment of dermatoses, obtaining the littie morbidity to your patient, and tissue diagnosis correct diagnosis is critical. In fungal infections, is definite. Rather then be pretty sure, get topical and/or oral antifungals are appropriate. For confirmation. It makes you a better clinician and it is dermatitis and eczema, topical steroids are the in the best interest for your patients. To illustrate, I mainstay of treatment. Therefore, depending on the can remember a case of an J0-year-old male who location of the rash (dorsal foot versus plantar had a dark raised, firm nodule on his Eareat toe, foot), a moderate to high potency topical steroid medial border I was certain it was a dermatofibroma can be considered. One should be cautious about because it looked like one. To my surprise, the using topical steroids more than 2 weeks at a time. pathology repofi came back as juxta-arlicular benign Once the rash is under control, lower potency neoplasm of borreliosis. Looking back on the case I topical steroid or Pimecrolimus 10/c: (Elidel), a noticecl in his intake (history) form that he topical non-steroidal anti-inflammatory cream, complained of fatigue and tiredness. Maybe his should be used for maintenance. symptoms were coincidental or possibly from Avoiding aggravating stimuli is impofiant too. borelliosis (Lyme Disease). For example, determining the undedying source for Famlliarizing yourself with clinical pictures of contact dermatitis is critical to prevent recurrence. dermatoses for recognition is impoflant, but uncler- For xerotic eczema, one should avoid more than standing the characteristics, location, and color of the one bath/shower a day, hot water, salts in the watet lesion should narrow your clifferential diagnosis to a and one should use hydrating creams immediately few entities. As a studenttesident, a dermatologist after the bathlshower. Dry skin has little to do with taught me to describe exactly what you see, i.e., a sil- lack of oils in the skin, but rather lack of water in very scale on an ery4hematous base (psoriasis) or an the skin (hydration). For patients with atopic eczema er),thematous patch with lichenification over the 1at- and psoriasis, avoiding harsh soaps when bathing eral malleolus (lichen simplex chronicus). In and using a non-soap cleanser such as Cetaphil can addition, the more you biopsy, the more confident be helpful. you get in recognizing lesions and their pafiicular disease process.