Being a GP is all about glamour isn’t it? That’s why we do this job. For the drama, the George Clooney-esq colleagues, the expensive shoes that never get
muddy on home visits and our beautifully coiffed hair that we all have hours each day to perfect. Well, not really. We know because all our ‘Hot ‘Topics
team are in the same boat as you. So we’ve parked the blogs on how to make sure your fake tan looks natural and what the latest superfood is and gone
for this one instead.
Scabies. Lovely. Because it’s not a sexy condition, there isn’t much in the way of new research on its treatment, the latest being from Clinical Evidence in 2014.
Remember scabies is an infestation of the skin by the mite Sarcoptes scabei. The incubation period is long (8 weeks). It’s spread through skin to skin contact, but it is thought to be possible to be passed by sharing bedding, and towels too. It’s most common in institutionalised communities (e.g. nurseries, schools and care homes) and amongst the most vulnerable – the very young, the very old and those with immune-deficiency. Outbreaks most commonly occur in the winter.
Typical sites of the infestation are between the fingers and wrists but also skin folds (buttocks, breast creases, genitals) and flexor surfaces where visible burrows may be seen. It causes intense itching driving patients mad, especially at night. More widespread eczema-like eruptions may occur. The burrows typically appear as small, greyish lines in the web spaces and flexor surfaces of hands, wrists, ankles and feet. The secondary eczema-like rash spreads over all the skin. In older people it may present as a diffuse truncal eruption, in infants and children the face, scalp, palms and soles are most commonly affected. Some good pictures here on Dermnet New Zealand http://www.dermnetnz.org/topics/scabies-images/
Despite these helpful photos, the main challenge with scabies is thinking of it in the differential in the first place. We see a lot of random rashes and itching in primary care, but if you see either in the very young or elderly, think scabies. The discomfort and itching is much worse in immunocompromised people. Severe, persistent itch and secondary infections can be debilitating. Occasionally, crusted (‘Norwegian’) scabies may develop which is then resistant to routine treatment. Look out for this in patients in nursing homes with dementia who aren’t able to communicate the itching and discomfort typically seen.
Best way to get rid of it? Topical permethrin is the most effective treatment (1a evidence) and highly effective at increasing cure rate at 28 days. Topical crotamiton is less effective than permethrin, but there is evidence that it is an effective treatment. Both of these preparations are better than topical malathion and benzyl benzoate which are often used as second-line agents but lack evidence of efficacy.
Although not based on RCT evidence, treating family members and close contacts at the same time as the index case is advised. Clothing and bed linen belonging to the index case should also be washed. Making sure patients apply the treatment correctly is the other challenge as it can be a faff. There are good patient information leaflets on NHS choices http://www.nhs.uk/conditions/Scabies/Pages/Introduction.aspx and on the British Association of Dermatology http://www.bad.org.uk/for-the-public/patient-information-leaflets/scabies
For patients who have treatment failure, are immunocompromised with severe symptoms, or those with crusted scabies, there is some RCT evidence that oral ivermectin is effective. This drug is only available on a named patient basis’ and is usually given as two doses taken one week apart. Consider referral for these cases of treatment resistant or severe cases (e.g. crusted scabies in patients with HIV/AIDs) for consideration of this.