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The complaint of rash as the presenting symptom in the outpatient setting is relatively common. A large survey of outpatient visits listed “rash” as the presenting symptom in 5% of all clinical encounters. The complaint of “rash” simply implies a widespread or localized eruption of similar primary or secondary skin lesions with an acute or gradual onset. This is in contrast to a patient presenting with a complaint of a “worrisome skin lesion(s)” which implies a benign or malignant neoplasm. Rashes are often accompanied by symptoms of itching (pruritus), burning, stinging, and/or irritation. Therefore, rashes can be disabling and interfere with concentration, sleep, and interactions with significant others and colleagues. Diagnosing the type and etiology of rashes is an important training problem for medical students because accurate diagnosis requires enhanced visual and tactile skills along with accurate use of the vocabulary of dermatology. Finally, rashes may provide clues to potentially life-threatening internal disease.

Required Skills/Procedures:

1. Perform situation-appropriate (problem-focused or complete) history and physical examinations
2. Interpret clinical information to formulate a prioritized differential diagnosis
3. Guide the creation of a patient-specific management plan

Appropriate Setting: Inpatient and Outpatient

Expected level of Responsibility: Direct supervision with real patients

Learning Topics during encounters with a patient with RASH can include:

Medical Knowledge Learning Topics related to RASH:

1. Essential physical features of the primary skin lesions:

  • papule
  • nodule
  • mass
  • macule
  • patch (including erythroderma)
  • vesicle
  • bulla
  • urticaria
  • pustule
  • furuncle
  • cyst
  • plaque (occasionally listed as a secondary lesion)

2. Essential physical feature of the secondary skin lesions

  • scale
  • crust
  • erosion
  • ulceration
  • lichenification
  • excoriation

3. Description of skin findings in a concise form:

  • location
  • color
  • size
  • secondary changes
  • primary lesion
  • configuration
  • distribution

4. Diagnosis of eruptions based on the hierarchy:

  • primary lesion
  • secondary changes
  • configuration
  • distribution (as opposed to focusing on the distribution first and primary lesion last)

5. Broad categories of eruptions based on primary lesion:

  • papulosquamous (red scaly eruptions including macular, morbilliform, papular)
  • vesicular
  • urticarial
  • pustular

6. Common diagnoses and the typical presenting features of the eruptions from each of the broad categories including:

  • psoriasis
  • seborrheic dermatitis
  • eczema
  • morbilliform drug eruption
  • contact dermatitis
  • syphilis
  • tinea corporis
  • lichen planus
  • bullous pemphigoid
  • pemphigus vulgaris
  • herpes zoster
  • urticaria
  • erythema multiforme
  • folliculitis

Diagnostic Evaluation Learning Topics related to RASH

1. Age-appropriate medical history that differentiates among etiologies of disease, including:

  • eliciting a full description of symptoms
  • determining if the rash is associated with sexual activity
  • determining the patient’s risk for venereal disease
  • obtaining a description of all prior episodes of rash and how they were treated
  • determining the presence or absence of predisposing causes

2. Primary skin lesions on physical exam or clinical photograph

3. Description of skin findings in a concise logical form

4. Differential diagnosis based on the skin findings focusing on the primary lesion

5. Use of tactile sensations differentiating primary from secondary lesions

6. Utility of diagnostic and laboratory tests, both prior to and after initiating treatment, based on the differential diagnosis, justify ordering them, and interpreting the results

7. Identification of the patient’s problem from all of the problems listed in the differential diagnosis by combining scientific knowledge, information obtained in the clinical encounter and collective experience with similar patients

8. Communication of the diagnosis to the patient

Management Plan Learning Topics related to RASH

1. Preventive measures, including counseling and educating patients about sexual activity
2. Appropriate prescribing of topical and oral medications as well as appropriate use of consultants and referral to specialists
3. Refer for psychological support if indicated
4. Follow-up planning
5. Communication of the prognosis to the patient in a caring and compassionate manner
6. Communication of the treatment plan and follow-up plan to patient
7. Cost-effectiveness of the management plan

Potential Differential Diagnosis Topics Include:


  • cellulitis
  • folliculitis
  • herpes zoster
  • impetigo
  • meningococcemia
  • Rocky Mountain spotted fever
  • secondary syphilis
  • tinea corporis
  • varicella


  • atopic eczema
  • bullous pemphigoid
  • buttate psoriasis
  • lichen planus
  • nummular eczema
  • pemphigus vulgaris
  • pityriasis rosea
  • psoriasis vulgaris
  • seborrheic dermatitis
  • systemic lupus erythematosus


  • allergic contact dermatitis
  • erythema multiforme
  • morbilliform drug eruptions
  • urticaria


  • mycosis fungoides
  • squamous cell
  • melanoma
  • basal cell