QCan I use doxycycline instead of minocycline to treat CARP?

A
Rachel Printy, PA-C

Rachel Printy, PA-C

PA-C

Medically reviewed on 05.01.2024 by Mark Lebwohl, MD

CARP, or confluent and reticulated papillomatosis, is a hyperpigmented rash usually found on the neck, back, chest, and sometimes upper extremities of adolescents and young adults.

It is frequently mistaken for a fungal infection by the patient and/or nondermatology providers, and the rash can be quite pronounced and distressing to those impacted by it.

In a retrospective chart review between 2009 and 2020 within the Mount Sinai Health System that was published in the JAAD by Kuo et al, medical records of patients identified for CARP were reviewed for demographics, clinical findings, treatments, and treatment response.

One potential risk factor for developing CARP was carrying excess weight, with 31% of patients being overweight and 48% obese. Although the cause of CARP is not quite understood, it was theorized by the authors that it may result from dysbiosis, endocrinologic imbalances, or keratinization disorders.

What I find most interesting from this study was that there was no statistically significant difference in response rates to minocycline monotherapy versus doxycycline monotherapy.

Although prescribed courses of therapy with minocycline tended to be shorter than those with doxycycline (1.7 vs 2.6 months), recurrence rates were lower in those treated with doxycycline vs minocycline (0 vs 36%), with a mean of 13 months to recurrence for those in the minocycline group.

It’s hypothesized that it’s the anti-inflammatory properties of these 2 drugs rather than their antibacterial properties that are responsible for clearance.

It appears that both minocycline and doxycycline are effective monotherapy treatments for CARP. Factors like recurrence rates, accessibility and side effects may cause one drug to be favored one over the other, but both work.

References:

  1. Kuo AM, Kamat S, D’Ovidio TJ, et al. Association of confluent and reticulated papillomatosis with obesity and resolution after treatment with doxycycline: A retrospective cohort study. J Am Acad Dermatol. 2023;89(2):348-350. doi:10.1016/j.jaad.2023.01.050