PracticeUpdate: Dermatology & Rheumatology

AMERICAN ACADEMY OF DERMATOLOGY 73RD ANNUAL MEETING 8

Dr Sarah Chamlin discusses Zika-linked skin eruption, systemic drug therapy in children, cognitive behavioural therapy for eczema Sarah Chamlin MD, is Associate Professor of Pediatrics and Dermatology at Northwestern University Feinberg School of Medicine, and a member of the PracticeUpdate Dermatology Advisory Board.

Zika virus and paediatric derm update. Scott Norton Dermatologists need to be alert for the skin eruption of Zika virus infection. Zika virus, a Flavivirus, is part of a family of mosquito-borne viruses which includes West Nile virus and is transmitted by Aedes mosquitos, specifically A. aegypti and A. albopictus . Zika virus infection was first reported in the Zika forest in Uganda in 1947, which later spread to the Micronesian island of Yap, then French Polynesia. Further spread to Mexico, Central America, the Caribbean, and South America followed; the current epicentre is Brazil. Most often – 80% of the time – infection is asymptomatic, but 20% of individuals experience a mild viral illness that may include a rash, conjunctivitis, and arthralgia. Fever, myalgia, and headache may also be noted. The rash has been described as a generalised, erythematous morbilliform eruption. The differential diagnosis includes dengue and Chikungunya, although the rash and conjunctivitis are more prominent with Zika. Zika is also thought to cause lissencephaly – leading to the microcephaly reported in Brazil – Guillain-Barré syndrome, and acute disseminated encephalomyelitis. While only approximately 100 cases of Zika have been identified in the US, more are anticipated, possibly this summer; dermatologists may be on the front line to make this diagnosis. Controversies involving systemic drug therapy in children. Stephen Wolverton Clinical decision-making about drug use in paediatric patients with skin disease is often based on limited data that are extrapolated from adult data or paediatric data for another disease (eg, use of systemic drugs for juvenile idiopathic arthritis or Crohn’s disease). A few lecture pearls are listed below. • As a general rule, mg/kg dosing starts to roughly equal adult doses at around 45 kg. • While subcutaneous methotrexate dosing has approximately the same bioavailability as the oral formulation, subcutaneous avoids the first-pass effect in the liver and higher doses can be used. Unfortunately, the use of subcutaneous drugs is more limited in children due to pain. • A methotrexate test dose, 5 to 10 mg, with labs in 5 to 6 days may minimise pancytopenia risk. The paediatric dosing range for methotrexate is 0.2 to 0.7 mg/kg, and many patients respond at lower doses, even the test dose. • A FibroScan should be considered in children with a high BMI on methotrexate to reassure clinicians of long-term safety. While this scan is not routinely done

in children, it helps to decrease the number of liver biopsies done in adult psoriasis patients. • Evidence for use of methotrexate, azathioprine, and cyclosporine for severe and recalcitrant atopic dermatitis is present in the literature. Much less evidence is published for use of mycophenolate mofetil, which is probably the safest to use. Research options emerging for this population are omalizumab and dupilumab. • Several biologics are available for use in children with severe, recalcitrant psoriasis, including etanercept, adalimumab, infliximab, ustekinumab, and secukinumab. • Recent articles suggest less frequent laboratory monitoring for patients taking isotretinoin. Pregnancy testing in women is an exception to this, and triglyceride testing is the most volatile lab to follow, especially if elevated at baseline. The approach to lab testing that was reviewed was to stop monthly labs if stable after 2 months of testing. • There is no strong and supportive evidence proving an increased risk of depression and suicide or inflammatory bowel disease with isotretinoin use. Anecdotally, there may be a very small subpopulation at risk for quickly reversible depression. Cognitive behavioural therapy & biofeedback in the management of eczema. Carisa Perry-Parrish Children with atopic dermatitis may experience excessive itching, sleep disturbance, diminished quality of life, poor self-image, and peer teasing. Involvement of a paediatric psychologist in the care of severely affected patients may improve patient and family disease knowledge, treatment adherence, and coping. In addition, scratching reduction can improve disease severity. Behavioural treatment examples for scratching reduction include: • Habit reversal – Keep hands busy! Instead of scratching, squeeze hands together, sit on hands, draw or colour. • Praise children for behaviours incompatible with scratching – This will increase positive habits and reduce inadvertent reinforcement of bad habits. Saying “stop scratching” just doesn’t work. • Token system – Provide points or stickers for applying moisturisers or taking a bath. Earn points for engaging in habit-reversal techniques. • Stress reduction – Older children may benefit from stress-reduction techniques such as deep breathing, visualisation, and muscle relaxation.

PRACTICEUPDATE RHEUMATOLOGY & DERMATOLOGY