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At the heart of general practice since 1960

November 2007: Iatrogenic conditions

How can perioral dermatitis be distinguished from acne vulgaris?

What are the treatment options for a keloid scar?

What conditions are associated with steroid use?

How can perioral dermatitis be distinguished from acne vulgaris?

What are the treatment options for a keloid scar?

What conditions are associated with steroid use?

all GPs are familiar with the situation where a patient's condition has been made worse by treatment. One study, in the BMJ,1 looked at 18,820 consecutive hospital admissions and found that 1,225 were related to an adverse drug reaction. This gave a prevalence of 6.5%, with the reaction directly leading to admission in 80% of cases. The median length of stay was eight days, accounting for 4% of the hospital bed capacity.

The majority of side-effects are less serious and often will not be reported. However, many can be avoided with careful explanation and patient education.

1 Folliculitis caused by emollient use

Folliculitis is a potential side-effect of emollient treatment. Emollients are the mainstay of treatment for eczema but can block hair follicles, causing inflammation around the pilosebaceous unit.

Follicular plugging can be avoided if the emollient is spread onto the skin in the same direction as hair growth.2 Comparing the application with stroking a furry pet is useful in explaining this to patients.

2 Perioral Dermatitis

Perioral dermatitis is a condition consisting of papules, pustules, erythema and often scaling around the mouth. It is commonly mistaken for acne but the seborrhoea and comedones seen in acne vulgaris are absent.

Perioral dermatitis may be a side-effect of applying potent topical steroids to the face and may also be associated with the use of cosmetics.3 Around 90% of cases occur in women aged 20-45.

The condition responds to oral tetracyclines, but may require a 2-3 month course. Although the application of steroids may improve the rash in the short term, it is important to explain to patients that, in the longer term, steroids exacerbate the condition and should not be used.

3 Contact dermatitis

When dressings are applied to the skin for prolonged periods there is an increased risk of contact dermatitis, or contact eczema. The areas affected will typically be red and inflamed, and appear similar to atopic eczema.

Contact dermatitis can often be a challenge to treat. Patch testing can be performed to determine the cause and treatment is with topical steroids and by avoiding the allergen.

In the case shown in the picture there was a marked reaction to adhesive dressings around a slow healing ulcer at the site of an incisional hernia and previous abdominal surgery. The yellow crusting raised suspicion of secondary infection but swabbing failed to confirm this.

4 Contact dermatitis caused by a henna tattoo

When presented with any bizarre looking skin lesions, GPs should always consider dermatitis artefacta. However, in the case shown in the picture the patient was aware of the cause, which was a henna tattoo done while on holiday a few weeks before.

The reaction was not caused by the actual henna, but by para-phenylenediamine (PPD), which was added to the dye to make the tattoo appear darker. In the USA and Europe most parlours use pure henna and it is illegal to use PPD for body art in the UK, but in third world countries adding PPD is a more common practice.

As with other cases of contact dermatitis, treatment is with topical steroids. However, reactions to PPD may last for many months, causing pain and itching.

5 Non-healing lesion caused by dermatitis artefacta

When patients present with any nonhealing lesion, the possibility of malignant change must always be considered and a biopsy taken.

In the case shown in the picture, the woman had had a large, nonhealing ulcerated area on her scalp for a number of years. There was no rolled edge but attempts to get the lesion to heal had failed. Although the patient did not admit to picking the lesion, relatives reported that she was regularly seen scratching it.

Biopsy excluded malignancy and a diagnosis of dermatitis artefacta was made. In such cases the affected area is usually easily reached by the dominant hand.

6 Keloid Scarring

Hypertrophic scars are normal but enlarged scars that, although thickened, remain within the boundary of the original scar and usually regress by 18 months after onset. Keloid scars are similar to hypertrophic scars but extend beyond the boundary of the original scar. Their aetiology is unknown.

The face, shoulder, chest and back are particularly liable to this form of scarring and the possibility of subsequent keloid scarring needs to be considered before the excision of benign lesions is undertaken in these areas.

Hypertrophic scars are more common than keloid scars. The area affected does not extend beyond the initial area of scar tissue, but will thicken and become nodular. Hypertrophic scars usually settle without treatment. Hydrocolloid dressings may be useful.

Treatment of keloid scars is often challenging. Options include intralesional triamcinolone and cryotherapy. One study4 has shown that excision of the large scar followed by injection of steroid into the newly formed scar while it is small is an effective option in severe cases.

This should be carried out in secondary care.

7 Bruising in a patient on warfarin

Warfarin is a commonly used anticoagulant that interferes with the hepatic synthesis of vitamin K-dependent clotting factors. It is metabolised extensively in the liver via the cytochrome P450 pathway and will be affected by other substances that are also metabolised by this route, such as cranberry juice, which contains flavonoids.5

Drugs that may affect the INR of a patient on warfarin include:

• Antibiotics such as erythromycin and metronidazole

• Amiodarone

• Aspirin

• Paracetamol

• Omeprazole

• Influenza vaccines

• Phenytoin.6

Education and regular monitoring of a patient's INR are therefore very important.

In patients on warfarin, any trauma may result in more extensive bruising than normal, despite the maintenance of acceptably therapeutic INR levels, as in the case shown in the picture.

8 Telangiectasia

Telangiectasia, permanently dilated and visible blood vessels, is one of the side-effects of radiotherapy.

In the case shown in the picture telangiectasia was still evident many years after radiotherapy had been used to treat a basal cell carcinoma (BCC) on the patient's left cheek. For this reason surgery is usually the treatment of choice for a BCC unless the lesion is very large and the patient is elderly.

At the time the photo was taken, another BCC had developed, overlying the area of previous treatment.

Strong topical steroids can produce a similar appearance. One study has found that hyfrecation is an effective method of treating telangiectasia, post-radiotherapy, in patients with breast cancer.7

9 Tinea Incognito

With steroid creams now available without prescription, many patients treat rashes without first seeking advice. In cases of eczema this usually helps. However, where the diagnosis is actually a fungal infection the application of steroids will exacerbate the condition and change the appearance of the rash. This can make the fungal infection appear more like eczema and increase the chances that it will be incorrectly diagnosed and treated.

Whenever an area of eczema fails to respond as expected, GPs should always consider a secondary bacterial infection or whether it is actually tinea incognito. Skin scrapings should be taken if diagnosis is in doubt, and either inspected under a microscope after adding potassium hydroxide solution or sent for mycology.

10 steroid-induced Striae

Various factors alter the effect of topical steroids on the skin. These include the strength of the steroid, any underlying skin disease, the age of the patient and the location the steroid is applied to.

The flexures and creases require particular care when steroids are applied. For example, the groin and axillae tend to be moister than other areas and the extra hydration leads to increased absorption of the steroid.

In the case shown in the picture, absorption has led to the development of striae, one of the side-effects of strong steroid use. Although historically difficult to treat, topical tretinoin8 and laser therapy9 have been shown to be useful in some cases.

11 Oral candidiasis

Inhaled corticosteroids for asthma may result in oral candidiasis,10 which is often mistaken for a sore throat. Treatment is with antifungal lozenges.

In recurrent cases, patients may benefit from using a spacer device and should be advised to rinse their mouth with water after inhaler use. In patients with oral candidiasis who are not using inhaled corticosteroids, GPs should always consider other causes of immunosuppression, such as HIV.

12 Necrotising Fasciitis in a patient with immunosuppression

There are many side-effects associated with the use of oral steroids, including immunosuppression, which leads to an increased risk of infection.

In the case shown in the picture, the patient was taking prednisolone for Sweet's syndrome when he developed a sore eye. He thought that it was conjunctivitis and bought some drops to use. Two days later, when he was seen by a doctor, his eye was significantly worse. The diagnosis was necrotising fasciitis, which required extensive surgery and a long stay in hospital.

Necrotising fasciitis is a rapidly spreading inflammatory infection of the deep fascia usually caused by anaerobic bacteria. It is rare in children and has a high morbidity and mortality rate. Early diagnosis is vital and prompt radical surgery remains the treatment of choice.11

Folliculitis. Emollients may cause follicular plugging, leading to inflammation of the pilosebaceous unit Figure 1: Folliculitis caused by emollient use Perioral dermatitis may be mistaken for acne, but the seborrhoea and comedones seen in acne are absent Figure 2: Perioral dermatitis Contact dermatitis. Patch testing can be used to determine the cause Figure 3: Contact dermatitis Contact dermatitis caused by a henna tattoo. Treatment is with topical steroids Figure 4: Contact dermatitis caused by a henna tattoo Dermatitis artefacta. The affected area is usually easily reached by the dominant hand Figure 5: Dermatitis artefacta Keloid scarring. The face, shoulder, chest and back are all liable to this form of scarring Figure 6: Keloid scarring Bruising in a patient on warfarin may be more extensive than normal, even when INR is controlled Figure 7: Bruising in a patient on warfarin Telangiectasia, permanently dilated and visible blood vessels, is a possible side-effect of radiotherapy and strong topical steroids Figure 8: Telangiectasia Tinea incognito should be considered as a possible diagnosis if an area of eczema fails to respond as expected Figure 9: Tinea incognito Striae may be caused by the absorption of topical steroids Figure 10: Steroid-induced Striae Oral candidiasis can be caused by inhaled steroids. Patients should be advised to rinse their mouth after inhalation Figure 11: Oral candidiasis Necrotising fasciitis. Prompt radical surgery remains the treatment of choice Figure 12: Necrotising Fasciitis in a patient with immunosuppression Author

Dr Nigel Stollery
MB BS
GP, Kibworth, Leicestershire and clinical assistant in dermatology, Leicester Royal Infirmary

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