Making the diagnosis
A CRP diagnosis is made based on clinical presentation. The eruption usually begins as verrucous papules in the inframammary or epigastric region that enlarge to 4 to 5 mm in diameter and coalesce to form a confluent plaque with a peripheral reticulated pattern. CRP can extend over the back, chest, and abdomen to the neck, shoulders, and gluteal cleft. CRP does not affect the oral mucosa and rarely involves flexural areas.2 Although most cases are asymptomatic, mild pruritus may occur.1,2
A skin biopsy rarely is necessary for making a CRP diagnosis, but histopathologic findings include papillomatosis, hyperkeratosis, variable acanthosis, follicular plugging, and sparse dermal inflammation.1,3
Antibiotics usually clear this rash
Systemic antibiotics, most commonly minocycline 100 mg twice daily for 30 days or doxycycline 100 mg twice daily for 30 days, are safe and effective for CRP.1,5 Sometimes treatment is extended for as long as 6 months. Although CRP usually responds to minocycline or doxycycline, it is believed that this is the result of these drugs’ anti-inflammatory—rather than antibiotic—properties.1,2,5 Azithromycin is an effective alternative therapy.2,5
There is a high rate of recurrence of CRP in patients after systemic antibiotics are discontinued.2 Uniform responses to treatment and retreatment of flares have solidified the belief that antibiotics are an effective suppressive if not curative therapy, despite a lack of randomized controlled trials.5
Our patient was treated with minocycline 100 mg BID. After 1 month, the rash had improved by 70%. In 3 months it was completely clear and the treatment was discontinued.
CORRESPONDENCE
Robert T. Brodell, MD, Division of Dermatology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216; rbrodell@umc.edu