9: DERMATOLOGY

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CHAPTER 9 DERMATOLOGY

BENIGN SUPERFICIAL LUMPS

Benign superficial lesions, including moles, seborrhoeic warts, skin tags and sebaceous cysts, can be removed easily in the surgery by one or other of the following: curettage, cautery, cryotherapy or excision.

SKIN MALIGNANCIES

MALIGNANT MELANOMA

A GP might expect to see one malignant melanoma every 5 years in a list size of 2000 patients. The only effective treatment for melanoma is excision. It is therefore essential that an early diagnosis is made, while the tumour is still thin. Melanomas are extremely fast growing, developing over only a few months.

Management

All suspicious moles should be referred immediately for wide excision.

Patients with clearly benign lesions should be reassured, and prevention should be discussed; excise the lesion if appropriate.

Long-term prevention.

High-risk patients should be advised to examine themselves regularly and to know the signs of malignancy. They should protect themselves from the sun, avoid sunbeds and use sunscreens that protect against UVA and UVB with a sun protection factor of >15, e.g. Uvistat 20. Sunscreens can be prescribed on FP10 only for patients with photodermatoses who require high protection (SPF >15). Prescriptions should be marked with ‘ACBS’ (Advisory Committee on Borderline Substances).

Low-risk patients should also be advised to protect themselves from the sun and to use sunscreens with an SPF of at least 10.

SOLAR KERATOSES

These are more common on sun-damaged skin and in the elderly. They look like dry, cracked plaques. They have very low malignant potential, and can be treated with cryotherapy or fluorouracil cream bd for 2–4 weeks.

BASAL CELL CARCINOMA (RODENT ULCER) AND SQUAMOUS CELL CARCINOMA

These are commonly related to sun exposure. They both have raised irregular edges and may be ulcerated. The BCC may have a pearly border. These should be referred early for excision, radiotherapy or cryotherapy.

ACNE

More then half of British teenagers develop acne severe enough to warrant therapy. Acne can cause great emotional distress, and is usually easily treatable. It is exacerbated by hot, sweaty conditions, and any cosmetics used should be light and non-greasy. Sensitivity and understanding are important. Most sufferers will have already self-treated with OTC preparations.

Diagnosis

History.

Ask about past and present OTC and prescribed treatments.

Examination.

Look for comedones, erythematous papules and pustules on the face, chest or back. There may be pitted scars.

Tip

Most patients need to be reassured that their acne is very largely unrelated to the nature of their diet.

Management

Moderate acne

HIDRADENITIS SUPPURATIVA

This causes chronic papules and pustules, with scarring, in the axillae and/or groins. It can be treated with long-term oxytetracycline 500 mg bd. Some patients require plastic surgery.

ROSACEA

Topical steroids aggravate rosacea.

This is characterised by chronic, shiny facial erythema, especially over the cheeks and central forehead. It is exacerbated by heat, sun exposure, spicy food and alcohol. There may be papules and pustules. It occurs most commonly in middle-aged women. It can be treated with long-term oxytetracycline 500 mg bd, reducing, if possible, to a maintenance dose of 250 mg daily. Treatment may be continuous or intermittent. Metronidazole gel applied twice daily is an alternative treatment, and may be used, if necessary with oral antibiotics.

BACTERIAL SKIN INFECTIONS

CELLULITIS/ERYSIPELAS (STREPTOCOCCAL)

These two conditions may coexist. Erysipelas is a superficial infection, causing sharply demarcated tender erythematous areas. Cellulitis causes deeper infection, involving the subcutaneous tissues. Treatment is with oral penicillin (and, in the case of cellulitis, flucloxacillin, in case of staphylococcal involvement) or erythromycin alone if penicillin-allergic for 7–10 days. Advise bed rest. Occasionally, admission may be required for treatment with intravenous antibiotics.

BOILS (STAPHYLOCOCCAL)

See p. 198.

FOLLICULITIS (STAPHYLOCOCCAL)

This is sometimes seen in patients treated with topical steroid ointments for eczema, and as a result of shaving or skin friction. It should be treated with mild antiseptics, e.g. povidone-iodine, or, if severe, with oral flucloxacillin.

IMPETIGO

Impetigo is a common infectious condition of the skin, caused by Staphylococcus.

Diagnosis

History.

Impetigo starts as a slough, which hardens to form a yellow crust. It is usually painless and occurs anywhere on the body, but is most common on the face.

It often complicates other skin problems that involve a breach of the skin surface, e.g. cracked lips, cold sores, eczema or grazes.

Cold sores can be indistinguishable from impetigo.

Management

• Fusidic acid cream tds rubbed on the crusts will help to soften them and prevent the further multiplication of bacteria.

• For widespread or stubborn lesions, use flucloxacillin 250 mg qds for 5 days.

• Erythromycin is effective in patients allergic to penicillin.

Tip

Inform the patient that impetigo is contagious and an individual towel and flannel should be used. It is not necessary to avoid school once treatment has started.

ERYTHRASMA

This usually presents as a brown, slightly scaly area in the armpits or groins. It is asymptomatic and is produced by a Corynebacterium. It can be treated with topical imidazoles, e.g. miconazole, or topical fusidic acid, or with a 2-week course of oral erythromycin.

VIRAL SKIN INFECTIONS

WARTS

Diagnosis

Look for firm papules with a rough hyperkeratotic surface. Plantar warts (verrucae) may look like callosities (hyperkeratosis) and often have a dark centre. They can cause pain on walking.

Management

Tip

Warts and verrucae usually resolve spontaneously, the patient’s immune response overcoming the infection. Treatment is only necessary if the patient is troubled by the wart.

Treat with the daily application of a wart paint or gel containing salicylic acid (e.g. Salactol), having softened the wart in hot water for a few minutes and removed any dead tissue with an emery board or pumice stone. The paint should not touch surrounding healthy tissue. The treatment may need to be continued for 3 months.

Cryotherapy with liquid nitrogen can be used for warts resistant to wart paints. It is quite painful and therefore best avoided in small children. Warn the patient that a blister may occur after treatment. Multiple warts normally require more than one application, and the optimum interval between treatments is 3–4 weeks. Occasionally, resistant warts require treatment with curettage and cautery.

Planar warts should be left to resolve spontaneously, as they are difficult to treat effectively.

Children with verrucae should be allowed to use swimming pools, particularly if the verruca is covered with a plaster or a water-resistant gel (e.g. Salatac), or if a verruca sock (available OTC) is used.

For genital warts, see p. 47.

MOLLUSCUM CONTAGIOSUM

This consists of asymptomatic crops of firm, pink, pearly papules, some of which have a central depression. They resolve spontaneously usually after about 12 months, but occasionally they persist for up to 5 years. Resolution may be hastened by:

• squeezing each lesion in order to expel the central plug (parents of young children with molluscum can be advised to perform this)

• cryotherapy

• pricking the centre of each lesion with phenol on the end of a cocktail stick.

FUNGAL SKIN INFECTIONS

RINGWORM (TINEA)

This can involve feet (athlete’s foot), body, groin, scalp and nails. It is usually indirectly acquired as a result of contact with fungal hyphae in keratin debris. Athlete’s foot is frequently the source of groin ringworm.

Diagnosis

Examination.

Tinea pedis usually starts with macerated, irritable skin between the toes and may spread to the soles and dorsum of the foot.

Tinea corporis is characterised by red, circular, slightly scaly lesions which clear centrally and spread from the perimeter.

Tinea cruris presents as a well-demarcated, red, slightly scaly groin rash, and is most common in young men.

Tinea unguium causes thickened, yellow friable nails, and most commonly affects one or a few nails only.

Investigation.

Send off skin scrapings, subungual scrapings or plucked hair, as appropriate, for microscopy and culture. (Unfortunately, results are often negative despite the presence of tinea.)

Management

Skin.

Keep the affected skin clean and dry. Treat with a topical imidazole cream, e.g. clotrimazole, econazole or miconazole (apply 2–3 times daily, continuing for 14 days after the lesions have healed). Resistant cases can be treated with e.g. oral terbinafine 250 mg daily for 2–6 weeks or itraconazole 200 mg bd for 7 days.

CANDIDA INFECTION

Buccal mucosa.

This is common in babies. Treatment is with e.g. nystatin oral suspension 100,000 units qds after food or amphotericin lozenges 1 qds, both to be continued for 2 days after lesions have resolved.

Nappy rash.

See p. 91.

Intertrigo/angular stomatitis/chronic paronychia.

Keep the hands dry and use a topical imidazole cream.

PITYRIASIS VERSICOLOR

This is characterised by an area of scaly, confluent macules which are usually asymptomatic and on the trunk, upper arms or legs. Affected patches remain pale on tanned skin. Use a topical selenium sulphide, e.g. Selsun shampoo, on all affected areas. Leave on the skin for 10 minutes before washing off. Repeat every other night for 3 weeks. Persistence of hypopigmented areas does not signify treatment failure. Alternatively, use an imidazole cream each night for 2–4 weeks. Oral itraconazole 200 mg daily for 7 days is effective.

SEBORRHOEIC DERMATITIS

Tip

Seborrhoeic dermatitis is often confused with eczema.

This usually presents as red, scaly patches in the eyebrows or nasolabial folds. It is commonly associated with a scaly scalp (dandruff) and blepharitis. Use a topical antifungal, e.g. ketoconazole cream bd (‘SLS’ must be written on the prescription) or Canesten HC, continuing for a few days after the lesions have healed, and ketoconazole shampoo twice weekly for 2–4 weeks. Recurrence requiring repeat treatment is common.

PITYRIASIS ROSEA

This is an eruption of pink macules, mainly over the trunk, which are usually distributed in lines parallel to the ribs. No action is required, but a mild topical steroid will relieve irritation. The rash resolves spontaneously in 6–8 weeks.

GENERALISED PRURITUS

Where there is no obvious skin disease, all patients with persistent generalised pruritus should be investigated to exclude an underlying systemic disorder. Scabies is a common cause – burrows can be difficult to see (see p. 142).

Arrange FBC, ESR, LFTs, C&Es, fasting BS, TFTs, urine for protein and a CXR.

If no underlying cause is found:

• use an emollient regularly (see p. 139)

• consider use of a topical steroid cream and/or an oral antihistamine. Crotamiton cream can be helpful.

HAIR LOSS

Acute stress is often the trigger for diffuse hair loss. Thyroid disease, iron deficiency and drug side-effects should be excluded. There is no specific treatment other than treating any identifiable underlying cause.

Alopecia areata normally resolves within a few weeks, although episodes may recur. Exclude tinea and hairpulling or other trauma in patchy hair loss.

Androgenic alopecia may be arrested by the use of topical minoxidil, which is only available on private prescription or OTC.

EXCESSIVE SWEATING

GENERALISED

A cause is rarely identified, but consider menopausal flushing, hyperthyroidism or hyperpituitarism, and autonomic neuropathy.

LOCALISED TO THE AXILLAE, PALMS AND SOLES

• Apply 20% aluminium chloride hexahydrate roll-on antiperspirant (e.g. Driclor) to dry axillae, palms or soles each night, and reduce to 1–2 times weekly as improvement occurs.

• Smelly feet are usually due to bacterial superinfection of sweat. Treat with e.g. potassium permanganate soaks (1:10 000 aqueous solution) twice daily, until the smell has improved. (Potassium permanganate stains the skin.)

• Axillary odour can be treated with an antiseptic cream, e.g. chlorhexidine cream bd.

• Consider dermatological referral for iontophoresis, which may help palmar or plantar hyperhydrosis, or botulinum type A toxin injections (Botox). In intractable cases consider surgical referral for thoracoscopic sympathectomy (also treats severe facial blushing).

ECZEMA

Eczema affects 15% of children (clearing in 50% of them by the teenage years) and 2–10% of adults. Atopic eczema is not present at birth, but often appears within the first 2 years of life. It is associated with other atopic conditions (asthma and has fever).

‘Eczema’ is synonymous with ‘dermatitis’. Treatment is basically the same, whether the eczema is exogenous (allergic and contact dermatitis) or endogenous (atopic).

Diagnosis

The main symptom is itching. The main signs are redness, papules, vesicles and hyperkeratosis, and there may be weeping and crusting.

Unlike fungal rashes, which have a well-demarcated edge, eczema is more diffuse.

Management

General.

Sympathetic explanation is essential, especially to the parents of young children with atopic eczema. Assess possible irritants or trigger factors with a view to avoidance, if possible, e.g. contact with metals, detergent or woollen clothing, dietary factors, emotion, heat, cold. If appropriate, give details of local and national support groups (see p. 358). The skin should be kept clean and warm, and prolonged contact with water, detergent, etc. should be avoided. If the hands are affected, gloves should be worn at the sink etc.

Emollients.

Emollients moisten dry, scaly skin, and are the mainstay of treatment. They can be used at any time on dry skin, but are particularly useful at bathtime, when different preparations can be used in combination:

• soap substitute, e.g. emulsifying ointment

• bath oil, e.g. Oilatum emollient

• emollient cream after bathing, e.g. aqueous cream.

Ointments are more effective than creams, but in view of their greasiness they are less user-friendly.

Topical steroids.

Aim to use the weakest preparation sufficient to control the disease. Acute exacerbations should be treated with relatively potent steroids. The potency should be quickly reduced when control is gained. Try to avoid anything stronger than 1% hydrocortisone on the face or in infancy.

Steroid potency

• Mildly potent: e.g. hydrocortisone 0.5%, 1% (can be bought OTC for use on all parts of the body except the face) and 2.5%.

• Moderately potent: e.g. clobetasone butyrate 0.05% (Eumovate).

• Potent: e.g. betamethasone 0.1% (Betnovate).

• Very potent: e.g. clobetasol propionate 0.05% (Dermovate).

Other treatments.

Secondary infection should be treated with topical antibiotic cream or ointment (e.g. fusidic acid) or oral antistaphylococcal antibiotics (e.g. flucloxacillin or erythromycin).

Severe eczema on the limbs can be treated with bandages (wet wrapping) which may be applied overnight on top of steroid ointment or emollients, e.g. zinc paste and ichthammol bandage, zinc paste and coal tar bandage or simple elasticated tubular bandage. A community paediatric/eczema nurse may be available to instruct parents on their use.

A sedative antihistamine at night may help itching in exacerbations e.g. alimemazine 2.5–5 mg tds for children over 2 years old.

The role of diet in atopic eczema is contentious. Cow’s milk is the most commonly implicated food, and should be avoided for the first 6 months of life. Exclusion diets help a small number of children, and should only be undertaken with expert advice from a dietician.

Referral.

Consider referral if:

• eczema is resistant or aggravated by conventional therapy

• eczema is severe, for consideration of phototherapy or immunosuppression (e.g. tacrolimus). Consider a short course of oral steroids while awaiting an urgent appointment (e.g. prednisolone 20–30 mg od for 5 days)

• infection is a problem (bacterial or herpes simplex)

• there is a need to use long-term potent topical steroids

• wet wrapping/paste bandaging techniques need to be taught

• patch testing is indicated to investigate contact dermatitis

• there are occupational factors.

PSORIASIS

In total, 1.5% of the population are affected by this chronic inflammatory skin disease during their lifetime. It most commonly presents as multiple, large, well-demarcated, red plaques with thick silvery scales in a symmetrical distribution, often involving elbows, knees and scalp. Nails may be pitted. There is no cure and it is usually lifelong, with exacerbations and remissions. The patient should therefore be given detailed information on self-management. The Psoriasis Association can be helpful (see p. 358).

Psoriasis is often exacerbated by trauma, stress or infections.

STABLE PLAQUES

Management

• Emollients (see p. 139). These help to control the scaling and irritation, and their use should be encouraged in addition to other treatments.

• Vitamin D preparations, e.g. calcipotriol (Dovonex) ointment or cream bd.

• Topical steroids, e.g. Eumovate or Betnovate RD ointment bd (see p. 139). Useful in stable disease and when plaques are few in number.

• Proprietary tar preparations, e.g. Alphosyl and Exorex, and mild steroid/tar combinations, e.g. Alphosyl HC.

• Proprietary dithranol preparations, e.g. Dithrocream. Preparations should be applied daily to plaques and washed off after 30 minutes. Old clothes should be worn during application. Start with a low concentration (0.1%) and gradually build up to the maximum concentration which produces a therapeutic effect without irritation (up to 2%).

• PUVA, oral retinoids, methotrexate, ciclosporin, etc. If psoriasis is extensive or unresponsive to the above treatments, refer for these.

SCALP PSORIASIS

In contrast to the scalp changes of seborrhoeic dermatitis, the scalp lesions in psoriasis are easily felt.

Daily shampooing with coal tar shampoo, e.g. Polytar, is helpful, but by itself is unlikely to control thick plaques. Calcipotriol (Dovonex) scalp solution used twice daily, or topical steroid lotions (e.g. Betnovate scalp application) used on a daily basis or less frequently, may be prescribed in addition.

Mixtures of tar and salicylic acid, although messy, are particularly effective for severe scaling, e.g. Cocois scalp ointment, which should be applied to the scalp once weekly, or more often if necessary, and shampooed off after 2 hours or left on overnight. Mixtures of steroid and salicylic acid, e.g. Diprosalic scalp application, are also helpful.

GUTTATE PSORIASIS

These symmetrical plaques on the trunk and/or limbs are round, unlike the oval lesions of pityriasis rosea. They usually clear completely in a few months, but classic psoriasis may develop subsequently.

Perform a throat swab, as guttate psoriasis usually follows a streptococcal throat infection.

Use a mild tar-based cream, e.g. Alphosyl or Alphosyl HC, and consider referral for UVB phototherapy.

KERATOSIS PILARIS

This is a very common disorder where the hair follicles are plugged with keratin, causing rough skin. The commonest sites are the posterior upper arm and the lateral cheeks, and it usually presents in young women as a cosmetic nuisance.

Treat with mild keratolytics, e.g. salicylic acid 2–4% in soft white paraffin, or advise cosmetic exfoliation. Emollients are helpful.

HEAD LICE

Head lice are common, and a particular problem in young schoolchildren and their families. They present as an itchy scalp.

Management

Nit combs

Daily use of nit combs, ideally on wet, conditioned hair, is now advocated in preference to insecticides (particularly if the lice are few in number, or have shown resistance to insecticides), in order to eliminate new lice and therefore to break the cycle. Nit combs can remove lice at all stages of development. They will not remove empty egg-cases, which persist on the hair for some time.

Insecticides clear the lice at all stages except the very young eggs. The treatments should therefore be repeated after an interval of 7–10 days.

Lotions should be used in preference to shampoos, which are relatively ineffective. Use e.g. permethrin cream rinse. Rub into damp hair and rinse after 10 minutes.

Resistance to insecticides is becoming increasingly common. If a course of treatment fails to cure, a different insecticide should be used for the next course. Insecticides can be bought OTC. Essential oils, e.g. tea tree oil, may be used, mixed with shampoo prior to nit-combing, to help clearance. All members of a household should be treated. Parents should notify the school so that all members of the class can be treated.

SCABIES

The scabies mite spreads by skin to skin contact, e.g. holding hands with an infected person or sleeping in the same bed. It can take up to 6 weeks to develop symptoms after being infected. All household members and intimate contacts should be treated, to avoid reinfection. Commonly there are just a few mites on the skin, creating burrows, but the allergy to them causes generalised itch and mild rash.

• Treat with malathion lotion or permethrin cream (available OTC).

• Apply over the whole body from the neck down. Wash off after the recommended time (8–24 hours). Reapply treatment to hands every time they are washed within the treatment period. Reapply the same treatment 7 days after the first application.

• The itch takes 2–3 weeks after treatment to subside. (This can be treated with e.g. crotamiton cream ± hydrocortisone cream.)

• Wash all worn clothes and bedding.

OTHER SKIN INFESTATIONS

CRAB LICE

These are capable of living in all hair except scalp hair, which is too dense for them. The most common site is pubic hair. They are transmitted by close physical contact, usually sexual. Infection of children is not evidence of sexual abuse. Use aqueous preparations of e.g. malathion over the whole body. Instructions for use are as for head lice.

FLEA BITES

These usually present as multiple lesions around the ankles and calves. Often, only one member of the family is affected.

Use hydrocortisone ointment or calamine lotion on spots to relieve the itching (both can be bought OTC). Deflea pets, and spray insecticide on soft furnishings and carpets. Professional exterminators, via the Environmental Health Department, are sometimes needed.

BED BUGS

These are suggested by very large lesions on the face or hands, particularly when new lesions are found each morning. Bed bugs live behind wallpaper and skirting boards, not in beds. The Environmental Health Department should be called to treat the house.

ANIMAL MITES

These are suggested by itchy papules, principally on the abdomen, thighs and arms (i.e. the main sites of contact with an animal sitting on the sufferer’s lap). Treat the animal.

VENOUS ULCERS

These are the commonest type of leg ulcer and are associated with underlying venous disease. They commonly occur above the medial or lateral malleoli. Confirm aetiology by Doppler. The mainstay of treatment is to limit oedema by good compression bandaging. Nurses are very much the experts in this field.

Management

General measures

• Encourage weight reduction in those at risk. (This is usually extremely difficult to achieve.)

• Encourage mobility (and ankle flexing while lying and sitting). The leg should be raised above the level of the hip when sitting.

• Consider systemic causes. Check Hb and urine for sugar.

• Physiotherapy may be beneficial, e.g. exercises, gentle massage and local ultrasound.

• Consider the use of diuretics and analgesics.

Dressing and bandaging

• Clean the ulcer with saline or warmed tap water.

• Moisturise surrounding skin with e.g. 50% liquid paraffin and 50% soft white paraffin. If significant eczema is present, consider steroid ointments and/or a medicated paste bandage (allergy to these is not uncommon).

• Dressings should be changed only once or twice a week, or as necessary. The choice of dressing depends on the nature of the ulcer, patient comfort, presence of infection, etc. A non-adherent dressing may be all that is necessary if compression is being used.

• Compression must be avoided if there is any evidence of arterial insufficiency.

• When an ulcer has healed, a graduated compression stocking should be prescribed.

Infected ulcers

• Take a swab.

• Prescribe oral antibiotics, e.g. flucloxacillin, or, if foul-smelling, metronidazole.

• Treat cellulitis with oral penicillin and flucloxacillin, or erythromycin.

Slow-healing ulcers.

Consider:

• dermatology (ulcer clinic) referral

• varicose vein surgery. In younger patients this may prevent recurrences (see p. 270).

ARTERIAL ULCERS

These tend to occur over the shin or around pressure points.

• Confirm aetiology by Doppler (usually assessed by nurse).

• Consider referral to vascular surgery if ankle:brachial systolic pressure index (ABI) <0.8.

• Use light bandaging only. Compression bandages should be avoided.

• Treat pain and infection, if appropriate.

• Arterial ulcers usually take longer to heal than venous ulcers.

Churchills Pocketbook of General Practice

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