We’ve had a good Christmas and we were lucky enough to have a week away after Christmas with the kids which we were very grateful for, despite the 12-13 hour drive as the rest of the continent seemed to have the same idea. Long travel times, not drinking enough or eating enough fruit or vegetables, and a change in diet with lots of cheese and saucisson can all lead to an altered bowel habit in even the most regular amongst us.
Constipation and the management of constipation is a commonplace problem in both adults and children. I’m not a fan of laxatives personally; I think it’s much better to eat more fibre, drink more water and do more exercise but in some cases, that is not enough and laxatives are needed.
It is however worth pointing out that laxatives such as senna can also cause skin problems.
What skin problems can it cause?
Senna, which can also be called sennoside or senna glycoside is derived from the plants Senna. It is a classical example of something which is deemed ‘natural’ or ‘organic’ and hence thought to be superior or side effect-free but actually can cause side effects just like any other drug.
The common side effects that one would expect are abdominal cramps, diarrhoea, nausea and vomiting. Very little is elaborated upon on the skin side effects of senna.
So what are they?
A curious skin eruption called fixed drug eruption can occur in people, usually adults, taking senna. It can be a difficult diagnosis to make as not everyone proffers information on taking an over-the-counter laxative. However a recurring reaction in exactly the same patch of skin is virtually pathognomonic of a fixed drug eruption and careful history taking can reveal the culprit drug.
What about in children?
I had never heard about senna causing skin problems in children. This may be because in the UK, senna as a stimulant laxative is not recommended first line and should always be prescribed by a doctor for use in children under 12y.
It was interesting therefore to read of a case of senna induced napkin dermatitis in the September/October issue of the journal Pediatric Dermatology (a US journal).
[Kinariwalla N, Yun S, Waldman AR et al. A curious case of blistering dermatitis in a child. Pediatr Dermatol. https://doi.org/10.1111/pde.15634]
What happened in this case?
It was a case of a 32-month old girl who had chronic constipation, was still wearing nappies/diapers and her sole medication was an over-the-counter laxative containing senna. She presented with geometric red patches on both buttocks, some of which had blistered, and these occurred the day after the senna laxative had been given at bedtime.
How did they know it was the senna?
The authors obviously excluded other skin diseases and causes. A key feature is the geometric shape of the redness on the buttocks, described as diamond shaped with linear borders aligning with the edge of the nappy. It has also been reported, though infrequently in the literature.
[Cogley K, Echevarria A, Correa C et al. Contact burn with blister formation in children treated with sennosides. Pediatr Dermatol 2017;34(2): e85-e88. doi:10.1111/pde.13068]
Why does it happen?
It is thought that in children wearing nappies, senna-induced diarrhoea leads to prolonged skin contact due to the presence of the nappy. It is also suggested that there is a higher concentration of physiological digestive enzymes in the senna-induced stool and that repeated or prolonged contact of the buttock skin with these enzymes causes an irritant dermatitis or a chemical burn. Also nighttime dosing could mean that diarrhoea could be left undetected for longer or at least overnight.
So should I avoid giving senna to my child?
If your doctor has advised senna for your child then you should follow his/her advice. In the nappy wearing child, giving the senna in the morning, changing the nappy promptly after soiling, regular cleansing of the nappy area and applying barrier emollients with every nappy change and before naps to reduce contact of stool and urine with the skin will all help.
And on that note, I wish you all the very best of wishes for the New Year!
Kind regards,
Sandy
Dr Sandy Flann, Consultant Dermatologist.
