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Soutor 1e- Clinical Dermatology- Lecture 1- Diagnosis and Management of Skin Disorders- Pearls and Pitfalls
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Soutor 1e- Clinical Dermatology- Lecture 1- Diagnosis and Management of Skin Disorders- Pearls and Pitfalls
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Language: EN.
Segment:0 .
Segment:1 1. Diagnosis and Management of Skin Disorders: Pearls and Pitfalls.
DR. SOUTOR: Hello, I'm Dr. Carol Soutor, clinical professor in the Dermatology Department at the University of Minnesota.
Segment:2 2. Learning Objectives.
DR. SOUTOR: In this presentation, we will cover some of the pearls and pitfalls in the diagnosis and management of common skin disorders.
Segment:3 3. Diagnosis in Dermatology.
DR. SOUTOR: In the first section of this presentation, we will cover the main steps in the diagnosis of skin rashes. These steps include the identification and classification of the primary lesion, creation of the differential diagnosis, and confirmation of the diagnosis.
Segment:4 4. The Primary Lesion.
DR. SOUTOR: Identifying the primary lesion is the first step in the diagnosis of any skin rash. One should carefully examine the skin for lesions that are typical for the presenting rash. It is important to look for lesions that have not been scratched, treated, or are resolving, as these may not be typical lesions. It may be necessary to examine the entire body to find new untouched lesions.
DR. SOUTOR: Once you have found one or more such lesions, you can categorize them as follows in the next slides.
Segment:5 5. Types of Primary Lesions.
DR. SOUTOR: There are nine types of primary skin lesions. Macules and patches are both flat lesions, as seen in the lesions of tinea versicolor in Figure 1. Macules are less than a half centimeter in diameter, while patches are larger than a half centimeter. Some textbooks use one centimeter as the cut-off diameter, but we use the more commonly used half centimeter cut-off.
DR. SOUTOR: Papules and plaques are solid, elevated lesions, as seen in the patient in Figure 2, who has both atopic dermatitis and an allergic contact dermatitis due to nickel in the metal button of his blue jeans. The smaller lesions that are less than a half centimeter are papules, and the larger lesion around the umbilicus is a plaque. A nodule is a solid lesion with a dermal or subcutaneous component.
DR. SOUTOR: It is greater than a half centimeter in diameter, as seen in the amelanotic melanoma in Figure 3.
Segment:6 6. Types of Primary Lesions.
DR. SOUTOR: Vesicles and bullae are blisters which contain serum or less commonly blood. A vesicle is less than a half centimeter, and a bulla is greater than a half centimeter in diameter. The patient in Figure 4 has pemphigus. The smaller lesion in this patient is a vesicle, and the larger lesion is a bulla.
DR. SOUTOR: Pustules are cavities filled with pus and are less than a half centimeter, as seen in the lesions of pustular psoriasis in Figure 5. The pus may be sterile or have bacteria. A cyst is a cavity that is greater than a half centimeter in diameter. It may be filled with keratin or pus, as seen in the staphylococcal boil in Figure 6.
Segment:7 7. Pitfalls in Identification of the Primary Lesion.
DR. SOUTOR: There are several pitfalls in the identification of the primary lesion.
DR. SOUTOR: The patient may have scratched or squeezed the lesion, especially if the lesions are itchy. This may alter or partially destroy the morphology of these lesions. As you can see in Figure 7, the lesions in this patient's rash have been so excoriated that they cannot be identified as a papule, vesicle, or pustule. You are just seeing erosions due to scratching.
DR. SOUTOR: Another problem is that vesicles, bulla, and pustules may spontaneously break, leaving only crusts and erosions, as seen in the patient with bullous pemphigoid in Figure 8.
Segment:8 8. Pitfalls in Identification of the Primary Lesion.
DR. SOUTOR: Another thing that may be a pitfall is post-inflammatory hyper- and hypopigmentation may obscure or distract the clinician from identifying the primary lesion. This can be seen in the patient with stasis dermatitis in Figure 9.
DR. SOUTOR: Another common problem is that the examination may be taking place too early or too late in an evolving skin disease. For example, the patient in Figure 10 has resolving herpes zoster. At this stage in the rash, the characteristic vesicles or bulla are not seen. Only the dark crusts and erosions are present. Lastly, treatment with topical steroids or antifungal products may alter the characteristic appearance of the lesions.
Segment:9 9. Characteristics of Primary Lesions that May Aid in Diagnosis.
DR. SOUTOR: There are several characteristics of the primary lesions that may also aid in the diagnosis. Most common skin rashes have characteristic surface changes and color. The lesions may also have a characteristic shape, arrangement, and are often present on characteristic body locations. For example, the papulosquamous diseases of psoriasis and pityriasis rosea typically have scale on the surface of the lesions.
DR. SOUTOR: Lesions of atopic dermatitis may lichenify. The color of lesions may also be of some help in diagnosis, especially in tumors. However, most skin rashes have some variations of red hues that are not necessarily distinctive. The shape of the lesion is also helpful. For instance, annular lesions with a well-defined border and clearing in the center are typical for tinea corporis. The arrangements of the lesions may also be helpful, as in the group vesicles in herpes simplex and herpes zoster or the symmetrical generalized distributions of the lesions of morbilliform drug rashes.
DR. SOUTOR: Lastly, the location of the rash is very helpful in certain diseases, such as seborrheic dermatitis, which tends to present on the scalp, while pityriasis rosea tends to present primarily on the trunk.
Segment:10 10. Differential Diagnosis.
DR. SOUTOR: Once the primary lesions, their characteristic features, and locations have been identified, a differential diagnosis could be created by focusing on the primary lesion and the most common diseases associated with that lesion or the locations of the lesion and the diseases that are common in that location.
Segment:11 11. Differential Diagnosis Based Only on the Primary Lesion(s).
DR. SOUTOR: In this slide, we see how a differential diagnosis could be made just based on the type of the primary lesion. For instance, most primary pigment disorders, such as vitiligo and melasma, present as macules or patches. Most viral exanthems and drug rashes begin with macules in the first day or two. Papules and plaques are characteristic of most common skin rashes, such as dermatitis and psoriasis.
DR. SOUTOR: Vesicles and bulla are characteristic for the acute phases of some forms of dermatitis, zoster varicella infections, and the immunobullous diseases, such as bullous pemphigoid. Lastly, pustules are seen in such diseases as acne and folliculitis.
Segment:12 12. Differential Diagnosis Based on Location(s) of Lesions.
DR. SOUTOR: A differential diagnosis for a rash could also be based on the locations of the lesion. Once the primary lesion is categorized and the affected locations are identified, lists of diseases that are common in those body regions can be used to create a differential diagnosis.
DR. SOUTOR: You can refer to chapters 30 through 39 in the textbook for this information. One pitfall is that rashes in the oral cavity, genital, and intertriginous areas may not have surface changes, such as scale, that are characteristic for that rash in other body areas. Also, blisters tend to rupture more easily in the oral and genital regions, so typically only erosions are seen, as in many cases of genital herpes simplex.
Segment:13 13. Categories of Dermatoses (Rashes).
DR. SOUTOR: As you are creating your list of differential diagnosis, it is important to consider the five categories that common skin diseases fall into. These include dermatitis, papulosquamous diseases, urticaria and drug rashes, infections, and the pilosebaceous diseases.
Segment:14 14. Two Broad Disease Categories.
DR. SOUTOR: These five categories can be divided into two broad categories that can help you to guide treatment.
DR. SOUTOR: First, there are the inflammatory diseases that respond to steroids, including dermatitis, the papulosquamous diseases, such as psoriasis and seborrheic dermatitis, and the common morbilliform drug rashes and urticaria. I should note that although urticaria will typically improve with systemic steroids, these are not commonly used as first-line therapy. The other large category is diseases that are related to microbes and respond to antimicrobial medications.
DR. SOUTOR: These include bacterial, viral, and fungal infections and the pilosebaceous diseases, such as acne, rosacea, and folliculitis. These diseases typically worsen with steroid treatment. Several common infections, such as tinea corporis, are often misdiagnosed as dermatitis and vice versa, so it is important to distinguish between the inflammatory diseases and infections.
Segment:15 15. Laboratory Confirmation of the Diagnosis.
DR. SOUTOR: Most common rashes can be diagnosed on the basis of physical findings.
DR. SOUTOR: However, laboratory testing may be needed if an infectious disease or an infestation is suspected. Skin biopsies may also be helpful for certain rashes, such as psoriasis, lichen planus, and the bullous diseases. However, skin biopsies often have nonspecific findings in dermatitis and may not be diagnostic.
Segment:16 16. Common Laboratory Tests for Dermatoses.
DR. SOUTOR: In many cases, potassium hydroxide examinations, fungal cultures, bacterial cultures, viral cultures, or polymerase chain reaction tests, Tzanck tests, and scabies scraping should be done to confirm the diagnosis of infections and infestations.
Segment:17 17. Other Diagnostic Aids.
DR. SOUTOR: Patch testing is helpful to confirm the diagnosis of allergic contact dermatitis and to identify the antigen that is causing the dermatitis. Dermoscopy is a valuable tool in identification of melanocytic tumors, such as nevi and melanoma. Also, most types of tumors have characteristic findings on dermoscopy. The Wood's light can be used to identify areas of hyper- and hypopigmentation, and it is useful in the identification of tinea capitis due to Microsporum species.
Segment:18 18. Diagnosis of Tumors.
DR. SOUTOR: Most benign tumors can be diagnosed by their clinical findings. However, skin biopsy is needed to confirm the diagnosis of a malignant tumor.
Segment:19 19. Summary.
DR. SOUTOR: In summary, identification of the primary lesion is an important first step in diagnosis. Most dermatoses can be diagnosed on the basis of their clinical findings. But as noted, laboratory tests may be needed to confirm the diagnosis of an infectious process.
DR. SOUTOR: Suspected malignant tumors need to be biopsied to confirm the diagnosis.
Segment:20 20. Treatment of Common Dermatoses.
DR. SOUTOR: Next, we will cover some of the perils and pitfalls in the treatment of common skin disorders.
Segment:21 21. Products for the Management of Common Dermatoses.
DR. SOUTOR: The following products will be covered in the next slides.
Segment:22 22. General Considerations for Use of Topical Products.
DR. SOUTOR: There are some general considerations that apply to all topical medications. These include vehicle selection, quantity of medicine to use, and quantity to dispense.
Segment:23 23. Selection of Vehicle.
DR. SOUTOR: The selection of the proper vehicle can be as important as the active ingredient in a topical medication. It can influence the effectiveness and tolerability of the medication and patient compliance. Ointments are petroleum-based products that are the best vehicle for dry dermatoses, such as atopic dermatitis and psoriasis. Creams are more drying than ointments. They leave less residue on the skin therefore, they are more cosmetically acceptable than ointments.
DR. SOUTOR: They are a good choice for acute, weeping, blistering dermatoses. However, patients may complain of stinging or burning after a cream is applied. Lotions are basically creams with more added water and are very cosmetically acceptable. Lotions are commonly used in moisturizers and sunscreens. A gel has a transparent base, which can be quite drying. Gels are generally used for acne medications and for hair-bearing areas.
DR. SOUTOR: Solutions are composed of water and/or alcohol. They are the best choice for scalp rashes. Foams leave minimal residue and are also best for scalp rashes and hair-bearing areas. Lastly, powders are useful for fungal infections in the body fold areas.
Segment:24 24. Quantity of Medication per Application and per Prescription.
DR. SOUTOR: The quantity of a medication per application and per prescription is another important consideration. It takes approximately 30 grams of a cream to cover the entire adult body for one application.
DR. SOUTOR: As an approximation, infants will need 1/5 of the adult quantity, children 2/5 of the adult quantity, and adolescents 2/3 of the adult quantity of medication. Topical medications are usually packaged in increments of 15 grams, most commonly in tubes and bottle sizes of 15, 30, 45, and 60 grams.
Segment:25 25. Fingertip Unit (FTU).
DR. SOUTOR: The fingertip unit is used as a guideline for patients on how much medication to use per application.
DR. SOUTOR: It is the amount of medication dispensed from a tube that covers the skin of the index finger from the tip to the distal crease. One fingertip unit is equivalent to approximately a half a gram, and it'll cover an area of skin equivalent to the area covered by two hands.
Segment:26 26. Commonly Used Topical Steroids.
DR. SOUTOR: Topical steroids are among the most commonly used medications for skin rashes.
DR. SOUTOR: In the United States, topical steroids are ranked from one to seven based on their potency, with Class 1 steroids being the most potent and Class 7 steroids being the least potent. In general, most common dermatoses can be treated with a small number of topical steroids, as there is little difference between steroids in any one class. Hydrocortisone and desonide are the most commonly used low-potency steroids, triamcinolone is the most commonly used medium-potency steroid, and fluocinonide is the most commonly used high-potency steroid.
DR. SOUTOR: If needed, a super-potent steroid, such as clobetasol, can be used in some clinical cases.
Segment:27 27. Factors in the Usage and Selection of Topical Steroids.
DR. SOUTOR: There are several factors to consider in the usage and selection of topical steroids. Most acute inflammatory diseases, such as contact dermatitis and atopic dermatitis, will respond to medium- to low-potency topical steroids. However, short-term use of more potent steroids may be needed for initial treatment or flares of these conditions.
DR. SOUTOR: Chronic localized dermatoses with thick lesions, such as psoriasis, may require higher-potency topical steroids. Areas of thin skin, such as the face, axilla, groin, diaper areas, and other intertriginous areas, should be treated with low- to the least-potent steroid.
Segment:28 28. Factors in the Usage and Selection of Topical Steroids.
DR. SOUTOR: Medium- to low-potency steroids should be used if large areas are to be treated to minimize the amount of steroid that could be absorbed systemically.
DR. SOUTOR: If a super-potent topical steroid, such as clobetasol, is used, the package insert recommends use for no more than two consecutive weeks and no more than 50 grams per week. It is important to note that children have a higher ratio of total body surface to body weight, and they are more likely to have systemic adverse effects from topical steroids, so low-potency steroids are recommended.
Segment:29 29. Topical Antifungal Agents for Dermatophyte Infections of the Skin.
DR. SOUTOR: The imidazole and allylamine topical antifungal medications are the most commonly used topical antifungal agents. As you can see, many of them are available over the counter. Most of them are effective against dermatophytes and yeast. It is important to remember, though, that nystatin is only effective against yeast, and it should not be used if the rash could be caused by a dermatophyte.
Segment:30 30. Oral Antifungal Medications.
DR. SOUTOR: Dermatophyte infections of the scalp require an oral antibiotic, such as griseofulvin.
DR. SOUTOR: Extensive or severe tinea corporis, pedis, manuum, and cruris also may require oral griseofulvin. Toenail infections due to dermatophytes can be treated with oral terbinafine or itraconazole if there are no contraindications to their use.
Segment:31 31. Topical Antibiotics.
DR. SOUTOR: Topical antibiotics can be used for impetigo and other superficial bacterial infections of the skin. Mupirocin and retapamulin are prescription-only products for gram-positive infections.
DR. SOUTOR: Bacitracin and neosporin ointments are commonly used over the counter antibiotics, but they can cause an allergic contact dermatitis. Topical clindamycin can be used for acne.
Segment:32 32. Oral Antibiotics.
DR. SOUTOR: Oral antibiotics may be needed for more widespread superficial bacterial infections, boils, and cellulitis. The cephalosporins, dicloxacillin, amoxicillin/clavulanate, or azithromycin are commonly used antibiotics for gram-positive infections.
DR. SOUTOR: Tetracycline, doxycycline, and minocycline can be used for moderate to severe acne or rosacea if these diseases have not responded to topical therapy.
Segment:33 33. Oral and Topical Antiviral Medications.
DR. SOUTOR: There are several topical and oral medications that can be used for certain viral infections. Topical acyclovir, docosanol, and penciclovir may be helpful for herpes simplex infections, although the frequency of dosing may be a drawback. Oral acyclovir, valacyclovir, and famvir can be used for herpes zoster or for more severe cases of herpes simplex infections.
Segment:34 34. Oral Antihistamines for Urticaria and Pruritus.
DR. SOUTOR: The H1 non-sedating antihistamines listed here are helpful for daytime management of urticaria and pruritus. The H1 sedating antihistamines can be used at bedtime, but the patient should be warned of soporific effects, which could last for several hours. As you can see, many of these medications are available over the counter. Occasionally, an H2 antihistamine is added in the treatment of urticaria.
Segment:35 35. Topical Antipruritic Agents.
DR. SOUTOR: There are also several over the counter lotions containing calamine, camphor, menthol, or pramoxine that can be used to reduce the symptoms of pruritus. Commonly used nonprescription products include Sarna Original Anti-Itch Lotion, Aveeno Anti-Itch Lotion, and Eucerin Calming Itch-Relief Lotion. Prax Lotion is a prescription-only product that can be useful for perineal and genital pruritus.
Segment:36 36. Hypoallergenic Moisturizers and Cleansers.
DR. SOUTOR: Hypoallergic moisturizers and cleansers may be needed in some rashes, such as atopic dermatitis and contact dermatitis. These products have fewer ingredients that are known to cause allergic or irritant contact dermatitis. Petroleum jelly is a good choice for patients who cannot tolerate other topical products. The products listed here are widely available.
Segment:37 37. Summary.
DR. SOUTOR: In summary, vehicle selection is an important consideration when prescribing or recommending topical products.
DR. SOUTOR: A limited formulary of cost-effective medications is sufficient to treat most common cutaneous skin conditions.