Summary
Dermatology is the branch of medicine concerned with the skin, hair, and nails as well as the conditions associated with them. Basic knowledge of dermatology is essential for every physician, as approximately 50% of skin-related consultations are initially assessed by non-dermatologists. In the United States, the most common conditions seen by dermatologists include acne, actinic keratoses, non-melanoma skin cancers, benign tumors, and contact dermatitis. Skin lesions may be primary or secondary. Primary lesions (e.g., macules and papules) appear as a direct result of a disease process. Secondary lesions (e.g., scales and ulcers) may develop from primary lesions or result from external trauma (e.g., infections, scratching). Dermatological conditions can often be diagnosed based on patient history and physical examination but confirming the diagnosis may require laboratory testing or biopsy. Dermatological diseases are managed with medication (topical and systemic) and procedures such as surgery, cryoablation, radiotherapy, or phototherapy. Conservative treatment with topical agents is the treatment of choice for most dermatological conditions, with systemic medication and/or surgery being employed only if necessary. The prevalence, manifestations, and treatment of dermatological conditions in skin of color may vary depending on skin tone and genetic inheritance.
Patient history
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History of present illness
- Establish the chief concern
- Onset and duration
- Morphology and type of lesions
- Symptoms e.g.,:
- Pruritus
- Sensitivity to light
- Pain
- Fever
- Past medical history: Underlying diseases may be responsible for skin findings (e.g., erythema nodosum in chronic bowel disease).
- Drug history: Many drugs have cutaneous adverse and side effects. Be aware of potential drug interactions.
- Review of systems: e.g., diabetes, rheumatic diseases, infections, and endocrine disorders (e.g., hyperthyroidism)
- Family history: e.g., Café au lait spots in young children may be part of an inherited disease such as neurofibromatosis.
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Social history
- Work hazards (e.g., exposure to chemicals)
- Sexual history in genital dermatological manifestations. If an STI is diagnosed, sexual partners may also need to be informed and receive treatment.
Physical examination
Overview
- Complete skin assessment: Examine the skin (including the hands, mouth, and scalp) and nails for signs of dermatological conditions.
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Examination techniques
- Inspection
- Palpation: evaluation of consistency (e.g., softness, firmness)
- Typical skin tests, as indicated:
- Dermatoscope inspection, as indicated
- Confirmation of diagnosis: may require biopsy for histopathological examination (see “Dermapathology” below) and/or laboratory studies
The hands, mouth, scalp, and nails should not be overlooked during a dermatological examination.
Skin examination
- Determine the type of lesion: See primary skin lesions, secondary skin lesions, and complex skin lesions below.
- Record lesion characteristics
Physical examination
Nail examination
- Inspect and palpate nails (fingers and toes) and look for alterations of the nails.
Alterations of the nails | ||
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Clinical findings | Clinical examples | Possible underlying disease |
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Nail clubbing | |
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Melanonychia | |
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Examination of the hands
Alterations of the hands | ||
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Clinical findings | Clinical examples | Possible underlying disease |
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Hyperpigmentation of the palms | |
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Symmetrical swelling of proximal and distal interphalangeal joints | ||
Ulnar deviation of the fingers | ||
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Primary skin lesions
Overview of most common primary skin lesions [1][2] | |||
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Primary Lesions | Description | Cross-section | Clinical example |
Macule |
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Patch (dermatology) |
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Papule |
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Nodule (dermatology) |
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Plaque (dermatology) |
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Vesicle (dermatology) |
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Bulla |
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Wheal | | ||
Pustule |
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Secondary skin lesions
Overview of most common secondary skin lesions [1][2] | |||
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Secondary Lesions | Description | Illustration | Clinical example |
Scale (dermatology) |
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Crust |
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Fissure (cleft) | |||
Ulcer (dermatology) | |||
Erosion |
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Excoriation (scratch marks) | |||
Necrosis |
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Skin atrophy |
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Scar |
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Complex skin lesions
Overview of complex skin lesions [3] | |||||
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Complex lesions | Description | Clinical example | |||
Hemorrhage | Hematoma |
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Purpura (a subtype of hematoma that does not blanch upon the application of pressure) | Nonpalpable purpura | Petechiae |
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Ecchymosis |
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Palpable purpura |
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Rashes | Exanthem |
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Enanthem |
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Erythema |
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Erythroderma |
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Maculopapular rash |
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Further lesions | Lichenification | ||||
Eczema |
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Differential diagnosis of annular skin lesions
Overview of annular skin lesions | |||||
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Etiology | Location | Characteristics | |||
Erythema migrans |
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Tinea corporis |
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Erythema marginatum |
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Nummular eczema |
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Granuloma annulare |
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Urticaria |
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Erythema multiforme (EM) |
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Fixed drug eruption |
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Pityriasis rosea |
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Discoid lupus |
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Dermatopathology
Dermatopathology | ||
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Histopathologic finding | Characteristics | Examples of associated conditions |
Acantholysis |
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Acanthosis |
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Hypergranulosis |
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Hyperkeratosis |
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Parakeratosis |
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Spongiosis |
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Dyskeratosis |
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Overview of treatment
Treatment
- Topical medications
- First choice of treatment for most conditions; often preferred for treating dermatological conditions because they cause fewer systemic side effects
- Examples: antibiotics, antifungals, corticosteroids, cytotoxic agents, antipruritics, retinoids
- Systemic medications
- Procedures
- Other
Types of topical preparations [5]
- Creams
- Ointments
- Lotions, foams, and gels
Topical steroids
Topical steroids are the most frequently used topical treatment in dermatology.
- Most common side effects
- Examples
Agent | Potency | Indication |
---|---|---|
Hydrocortisone (1%) | Low | For mild and chronic dermatoses and for use on the face |
Triamcinolone (0.1%) | Medium | For intermediate severity dermatoses |
Clobetasol (0.05%) | High | For more severe dermatoses |
Phototherapy [6][7][8]
Ultraviolet light is an effective treatment option for dermatological conditions because of its antiproliferative (e.g., slowing of keratinization) and antiinflammatory effects (e.g., inducing apoptosis of pathogenic T cells).
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UVA therapy
- Indications: atopic dermatitis, scleroderma, chronic pruritus, prurigo simplex [9]
- Adverse effects
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UVB therapy
- Indications: psoriasis, vitiligo, chronic pruritus, atopic dermatitis [9]
- Adverse effects
- Acceleration of photodamage (e.g., sunburn)
- ↑ Cancer risk
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PUVA therapy: (psoralen plus UVA): topical or oral psoralen → ↑ skin photosensitivity → ↑ antiproliferative and antiinflammatory effects of UVA light
- Indications: psoriasis, atopic dermatitis, vitiligo, mycosis fungoides
- Adverse effects
- Nausea, vomiting
- ↑ Risk of squamous cell carcinoma
Skin of color
Overview
- “Skin of color” refers to skin with a higher degree of pigmentation than that traditionally associated with Northern European heritage.
- Skin tone is a spectrum that does not necessarily correspond to the skin tones traditionally associated with race.
- Genetic inheritance can play a more important role in the manifestation of dermatological conditions than skin tone.
- It is important to recognize with regard to the concept of “race” still in use by the US Census Bureau that there is no foundation for a scientific concept of race as a specific genetic, phenotypical, ancestral, or ethnic trait that distinguishes all members of one population from those of another.
- Western medicine has traditionally focused on the presentation of light-skinned individuals, leading to underrepresentation in dermatological resources of cutaneous manifestations in individuals with skin of color.
- Changing demographics and increased representation of historically marginalized populations have raised awareness for the need and importance of thoroughly understanding skin of color.
Epidemiology
- The incidence and prevalence of dermatological conditions in individuals with skin of color depend to a high degree on skin tone and differ from those seen in light-skinned individuals for a variety of reasons:
- Underrecognition due to poor dermatological training in diagnosing cutaneous conditions in individuals with skin of color.
- Factors that are influenced by different lifestyle and cultural practices
- Genetic inheritance
Dermatological conditions that are more common in individuals with skin of color [13][14][15] | |
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Heritage | Condition(s) with higher prevalence |
African |
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Southeast Asian |
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East Asian |
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West Asian |
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Latin American |
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American Indian |
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