II. Pathophysiology: Hypersensitivity Reaction
- Often idiopathic
- Pregnancy
- Dental Infection
- Insect Bites (Arthropod Bites)
- Foods
- Blue cheese ingestion (Penicillin reaction)
- Tomato ingestion
- Medication Reaction
- Ampicillin
- Thiacetazone
- Aldactone
- Spironolactone
- Hydrochlorothiazide
- Gold Sodium thiomalate
- Piroxicam
- Hydroxychloroquine sulfate
- Cimetidine
- Finasteride
- Amitriptyline
- Dermatophytes
-
Bacterial Infection
- Streptococcal infection
- Escherichia coli Urinary Tract Infection
- Tuberculosis
- Thyroid disease
- Viral Infection
- Malignancy
III. Symptoms
- Pruritus may be present depending on type
- No constitutional symptoms
IV. Signs
- Type I: Superficial Gyrate Erythema
- Annular Lesion with trailing scale within borders
- Pruritic
- Type II: Deep Gyrate Erythema
- Annular red lesion without scale
- Not pruritic
- Characteristics
- Red Plaque with central clearing
- Distribution
- Trunk
- Buttocks
- Thighs and legs
- Spared areas
- Does not affect Hands and Feet
- Does not affect Face
V. Differential Diagnosis
VI. Labs: Skin Biopsy
- Perivascular dermal Lymphocyte infiltrates
- Organized in coat-sleeve appearance
- Papillary edema
- Spongiosis
- Parakeratosis
VII. Labs: Evaluation for secondary cause
- KOH of lesion
- Antinuclear Antibody (ANA)
- Tuberculin skit test (TST or PPD)
- Complete Blood Count (CBC)
- Liver Function Tests
- Urine Pregnancy Test
VIII. Imaging: Evaluation for secondary cause
IX. Management
- High potency Corticosteroids (variable efficacy)
X. Course
- Lesions persist on average 9 months
- May resolve as early as 4 to 6 weeks
- May persist as long as 34 years as in one patient
XI. References
- White (1994) Regional Dermatology, Mosby-Wolfe, p. 264
- Hsu (2001) Am Fam Physician 64(2):289-96 [PubMed]