| Inflammatory |
| Allergic contact dermatitis | Common F > M Age: any age | Pruritus Onset: hours to days after contact with allergen | Acute: papules and/or vesicles on an erythematous base (Figures 8-4 and 8-5) Chronic: xerosis, fissuring, hyperpigmentation, and lichenification (Figures 8-1, 8-2, 8-3). Typical locations: axillae, waistline, and umbilicus |
| Psoriasis | Common M = F Age of onset: any age but peaks in 20s and 50s | Asymptomatic or mildly pruritic. Chronic May have history of arthritis and family history of psoriasis | Red papules and plaques with silvery, thick, adherent scale typically on lower back, umbilicus, buttocks, and gluteal cleft. Guttate psoriasis presents with multiple small scaly papules (Figure 9-5) |
| Seborrheic dermatitis | Common M > F Age: bimodal; peaks in infancy and adulthood | Asymptomatic or mildly pruritic. Intermittent with seasonal variation | Symmetric pink plaques with greasy scale on central chest |
| Pityriasis rosea | Common F > M Age: any, most common in children and young adults Seen in fall or spring | Variable pruritus, sometimes preceding nonspecific "flu-like" symptoms Spontaneous remission in 6-12 weeks | Begins with a herald patch, an oval, slightly elevated, salmon pink 2-5 cm plaque with trailing collarette scale. Later dull pink oval papules or plaques with fine scale develop symmetrically on trunk in "Christmas tree" distribution (Figure 9-9) |
| Infectious |
| Candidiasis | Common M = F Age: infants and adults, other ages when risk factors present | Pruritus, soreness Risk factors: pregnancy, immunodeficiency, obesity, diabetes, antibiotic and glucocorticoid use | Initially vesicopustules that rupture and coalesce leading to moist, macerated, red plaque with fissures with satellite pustules at periphery on inframammary, axillae, and abdominal skin folds (Figure 10-17) |
| Tinea versicolor | Common M = F Age: postpubertal | Asymptomatic rarely mild pruritus Duration: months to years. More common in summer and warm moist environments | 3-5 mm round to oval macules with fine scale, may coalesce and develop hypo- or hyperpigmentation or variable coloration on central back and chest and neck (Figure 10-14) |
| Tinea corporis | Common M = F Age: any, most common in preadolescents | Asymptomatic or mild pruritus. Spread by direct contact with infected humans, animals, soil, or autoinoculation from a dermatophyte infection present on other locations | Red, scaly papule that expands outward and develops into annular plaque with slightly raised well-demarcated border with peripheral scale (Figure 10-4) Central clearing may result in a "target-like" appearance |
| Folliculitis | Common M:F dependent upon etiology which may include non-infectious causes Age: any | Variable pruritus. Risk factors: occlusion, heat, humidity, diabetes, immunosuppression, trauma, and medications | Follicular-based papules or pustules May have surrounding red zone May have erosions or crust from secondary changes (Figures 15-8 & 15-9) |
| Infectious exanthems | Common Age: <20 years Viral pathogen most common, can be bacterial, mycoplasmal, rickettsial, or other | Prodromal symptoms including fever, malaise, coryza, sore throat, nausea, vomiting, diarrhea, abdominal pain, and headache Usually precedes cutaneous eruption by up to 3 weeks | Multiple presentations: scarlatiniform, morbilliform (Figures 27-1, 27-2, 27-3, 27-4, 27-5, 27-6), vesicular, and pustular Often accompanied by oral mucous membrane involvement, lymphadenopathy, hepatomegaly, and splenomegaly |
| Syphilis (secondary) | Uncommon M > F Age: 15-40 Risk factors: men who have sex with men | History of asymptomatic, genital ulcer several weeks to months prior to onset of rash. Systemic symptoms (fever, malaise, myalgia, and headache). May be present or shortly precede onset of eruption | Scattered ill-defined pink macules or red, scaly, well-defined papules symmetrically distributed on trunk (Figure 12-6) |
| Herpes zoster | Common M:F unknown Age: any age, but usually >50 years | Severe pain, paresthesias, or pruritus precedes eruption. Resolves over 2-3 weeks | Grouped vesicles on an erythematous base (Figure 11-4) that later crusts over a unilateral dermatome (usually thoracic) |
| Pilosebaceous |
| Acne | Common Teens: M > F Adults: F > M Age: adolescents and young adults | Asymptomatic, pruritic, or tender. Individual lesions may last weeks to months. Variable course Menstrual exacerbations | Open (black heads) and closed (white heads) comedones, erythematous papules, pustules, and nodules on upper chest and back (Figure 15-1) |
| Other |
| Drug eruption | Common F > M Age: any, most common in hospitalized patients | Symptoms, onset, and duration variable and depend on offending agent. History of recent changes or adjustments to medications Risk factors: elderly, concomitant viral infection | Morphology and distribution extremely variable, virtually every cutaneous reaction may be seen. Morbilliform most common, presents with small pink macules and papules, often starts on trunk and pressure-bearing areas, may generalize and become confluent (Figure 10-6) |
| Grover's disease (transient acantholytic dermatosis) | Uncommon M > F Age: ≥50 | Variable pruritus Abrupt onset with chronic course. Exacerbated by heat, sweat, sunlight, fever, and bedridden status | Discrete, scattered, and/or confluent red hyperkeratotic scaly papules sometimes with crust, erosion on central trunk, and proximal extremities |