See also Common for Exanthems.
Vesicular:
For more dramatic blistering:
Diffuse erythroderma – scarlet fever, strep/staph TSS, scalded skin before exfoliation.
Topical mupirocin or fusidic acid effective for local impetigo. Do not use if eczema present, because of need for prolonged and recurrent use, which would encourage resistance. Unfortunately, resistance to fusidin is emerging, and mupirocin should probably be reserved for MRSA! Of oral antibiotics, Pen V is the worst! (metanalysis, BrJGP)
Lesions toxin mediated so topical ab's not useful except umbilicus in baby (usual site of colonization, use mupiricin). Moisturize, Mepitel, lyofoam. Contact history.
Babies can have cyst, papule, and pustule types of acne esp boys, on cheeks! Resolution is frequently spontaneous, but fear of scarring. Treat with erythromycin bd.
The ladder of treatment commences with topical anticomedonal agents such as benzoyl peroxide or benzoyl peroxide + antibiotic combinations (eg Benzamycin gel or Zineryt). For mild non-inflammatory lesions (such as whiteheads and blackheads) or inflammatory lesions (such as papules and pustules) topical adapalene (Differin) is a good choice.
For moderate Acne, add oral antibiotics. These usually need to be taken continuously for 6 months. Propionibacterium acnes, the organism responsible for inflammatory acne is gaining resistance against many antibiotics. The drug with the least resistance is Minocycline (thus consider Minocin MR 100mg/day). Alternatives include lymecycline 408mg (ie Tetralysal 300mg o.d.). Tetracyclines are contra-indicated under 12 yrs due to dental staining.
At any stage, if appropriate, Dianette OCP can be considered in females. This has three benefits - contraception (probably unnecessary in the vast majority of <16year olds), decreased acne, reduced hirsutism.
For severe Acne refer to a dermatologist for consideration of isotretinoin. Side effects of isotretinoin are numerous and include:
Although mood changes (including severe depression) are listed in the side effect profile, it is difficult to be absolutely sure whether these are the usual emotions experienced by patients with acne or whether it is isotretinoin (surveys suggest 15% of acne sufferers have suicidal ideation).
History:
On examination:
Infants tend to get eczema on the face. Older infants get it on extensor surfaces. From walking age, antecubital and popliteal fossae.
Eczematous skin is predisposed to staph aureus infection, and treatment with steroid emollients alone reduces staph carriage, hence a vicious circle exists. Steroids are not contra-indicated, but consider a steroid-antibiotic combination e.g. Fucibet, tailing down to steroid only over a week as things improve. If severe, topical corticosteroids with oral flucloxacillin would be a good option.
A rough guide to the amount of steroid to use: 1 FTU (fingertip unit) covers area of 2 palms = 0.5 G. It is important to remember that undertreatment can be just as damaging as overtreatment. Strengths of steroid:
Tacrolimus 0.03% ointment has been licensed for use in children with moderate to severe atopic dermatitis unresponsive to conventional therapies. Application is twice a day at first for up to 3 weeks, reducing to once daily after three weeks until the atopic dermatitis is clear. More effective than mild topical steroid but not more than potent. No skin atrophy was observed when patients used it daily for up to 2 years. Should only be prescribed by doctors with adequate experience of treating with immunomodulatory agents; consider for patients vulnerable to steroid side effects. For unresponsive patients, referral to a dermatologist for wet-wrap bandaging, a short course of cyclosporin or ultra-violet treatment, in-patient care.
Pimecrolimus has been tested only in mild to moderate disease and has not been compared to mild topical steroids. It is not as effective as potent steroids. Tacrolimus and pimecrolimus have not been compared with each other. Tacrolimus and pimecrolimus are approximately 10 times more expensive than topical steroid preparations. (Arch 2004; 89)
Chronic, relapsing course in childhood and then improves with 60-90% of children clear by 10-16.
BMJ 1999;318:1600-4
Eczema herpeticum can spread rapidly, forming extensive sheets of monomorphic eroded or umbilicated vesicles. Treatment is with aciclovir 200mg 5x a day for 5 days. Parents of children with eczema who have cold sores should be warned not to kiss their children until the sore has healed.
Malassezia furfur is a fungus, IgE antibodies to which are found more commonly in eczema patients. Use of antifungals is under investigation.
Eczema patients have lower populations of bifidobacillus, which induce Th1 responses. Giving lactobacillus has been shown to be useful in a double blind placebo trial.
Guttate (Latin gutta for drop) psoriasis is acute, developing suddenly 10-14 days after a streptococcal sore throat. Persists for 2-3 months and then resolves spontaneously! Occasionally, it can persist for more than one year. Responds very well to narrow band UVB therapy if embarrassment is an issue.
Treat flare ups with increased steroid. If flare returns on reducing steroid, maximize coal tar: 1% for a few days, then 2%, then 5% as tolerated. Trimovate for groin, flexures & hairline. Oil of Cade 6%/sulphur 3%/salicylate 3% to scalp bd, increase to 12%/6%/6% as tolerated. Polytar shampoo BD for scalp.
Starts with a Herald Patch - single oval scaly plaque 2-3 cm in diameter - then spreading to the trunk with individual papules distributed in parallel to the ribs, may have a collarette of scale. The peak incidence is in spring and autumn. The rash is lighter pink in colour than, say, psoriasis. Self-limiting eruption, gets better in about 6 weeks. Must be infective, but unknown agent! HHV 6? 7? Pityriasis versicolor is completely different: see below.
Due to yeast (Malassezia furfur). Causes depigmented streaks, typically on the trunk. Most apparent after sun exposure when normal skin goes darker. Treat with topical miconazole.
Lasts 2-6/52, ages like a bruise, relapsing. Child is usually older than 10 yr. Possible diagnoses:
Consider CXR/mantoux. Treatment is with NSAIDs/pred.
Lyme – tick bite only recalled in 30% of patients. Needs at least 36 hours to feed and transmit. Erythema marginatum classically in armpit or other moist area, can be multiple (due to spirochaetaemia). Serology high false positive rate so Western Blot for antigen. Doxycycline is drug of choice for over 8 yrs, else amoxicillin or ceftriaxone. 2-3 weeks treatment, 4 weeks if arthritis.
Two-thirds of common warts involute spontaneously within 2 years. Pain, cosmetic embarrassment or interference with function are reasonable reasons for treatment. One regimen is to treat with two freeze-thaw cycles for 5 to 15 seconds depending on thickness and repeat at 2 to 3 weekly intervals (cryo spray and cotton bud applicators appear to be equally efficacious). Be careful in racially pigmented skin as hypopigmentation can result, and over tendons as there have been reports of tendon rupture after cryotherapy.
Alternatives are salicyclic acid applied topically after paring each night for three months, curettage and cautery, pulsed dye and carbon dioxide laser and more recently, in clinical studies, imiquimod, although very few cases should necessitate the latter treatments.
Filiform warts are long, narrow, and have protruding finger-like shape to their appearance, usually on the eyelids, face, neck, or lips (eg witches). They are best managed by curettage and cautery.
Serpiginous burrows between the fingers, in the flexures of the wrist, genitalia etc characteristic but rare. More usually papules, pustules - pruritus often on unaffected skin and esp at night. In infants, lesions on head, nappy area, occ palms and soles. Rash is partly hypersensitivty so not related to number of mites, may take several weeks after inital infestation to appear - on reinfection just a few days. Cross reaction with related house dust mite. Topical steroids will mask rash/itch. Superinfection common. Differential is contact dermatitis, animal scabies (do not form burrows, do not complete life cycle so self limited), lichen planus.
Rarely, nodular form (esp groin, axillae) - hypersensivity reaction. Norwegian or crusted scabies esp immunosuppressed (but not necessarily) - psoriaform, not always itchy, very infectious. Caused by the mite sarcoptes scabiei, which do not fly or jump; infection by contact with fomites is very rare.
Treat with Permethrin 5% (=Lyclear) dermal cream [Permethrin 1% rinse cream ineffective in scabies cf head lice]. Safe in infants (rarely CNS side effects). An alternative treatment is Malathion (safe in pregnancy). All household members should be treated simultaneously. After treatment the itching from scabies can take weeks to settle. Treatment should be extended to the scalp, neck, face and ears in children up to the age of 2 years. All skin surfaces should have the agent applied for 24 hours for malathion and for 8-12 hours for Permethrin 5% and have treatment repeated at 7 days.
Oral ivermectin in single dose is effective in over 70%, given twice 2 weeks apart 95% effective. Use for crusted (along with keratolytics), epidemics. Lancet Infectious Diseases Volume 6, Number 12, December 2006
A live louse must be identified to confirm active infection. Permethrin 1% cream rinse should be applied to clean damp hair, left on for 10 minutes and then rinsed off. Treatment should be repeated at seven days, if live lice are found. Use malathion in pregnancy (no data for permethrin). All house hold members should be treated. Failure of treatment could be due to incorrect diagnosis, incorrect application of the agent or resistance by lice. Some lice are showing resistance to insecticides in certain regions and this is an important cause of treatment failure. In this case - change to a different insecticide (eg Derbac M, Quellada M, Suleo M, Prioderm) and instruct mum to rub liquid (0.5%) into dry hair and scalp, remove by washing after 12 hours OR apply shampoo (1%) to wet hair, rinse after 5 minutes, comb wet hair. Repeat this in 3 days time and then after a further 3 days.
Consists of well-circumscribed target-like lesions most commonly on the extremities. In about half of cases the cause is never found. Causes include:
Note how some causes are the same as erythema nodosum. Blistering can occur, and EM is considered a spectrum disorder with Toxic Epidermal Necrolysis and Stevens Johnson syndrome at the extreme end. There is no clear evidence that steroids help in erythema multiforme. Treatment is symptomatic support.
Closely related. Usually treated with steroids but controversial since some retrospective studies showed harm. IVIg given in addition is effective, although has been associated with nephrotoxicity in adults. Unclear whether steroids are really needed at all. (PIDJ 2004)
Infantile seborrhoeic dermatitis can affect the nappy area but tends to affect the creases. It tends to be salmon coloured with greasy yellowish scale. There may be seborrhoeic dermatitis elsewhere, for example the face and scalp (cradle cap).
Nappy rash is an irritant contact dermatitis affecting the skin where the moist nappy is in contact. It spares intertriginous areas. An allergic rather than irritant contact dermatitis can occur, but is uncommon in children <2 years. Change nappies 6-8 times a day, dry thoroughly, use barrier eg zinc oxide cream. Differential diagnoses to be considered also include candidiasis, atopic dermatitis, psoriasis, intertrigo, bullous impetigo and the rare Langerhans cell histiocytosis.
Zoster begins with pain and an erythematous maculopapular, then vesicular, rash in a dermatomal distribution. Adjoining dermatomes can be involved, and a few crops of vesicles are sometimes scattered outside the primary eruption. During the course of 1 week, the rash becomes pustular and then ulcerates and crusts. Healing occurs within weeks and sometimes results in scarring. VZV can be cultured from the blister fluid but may not survive in transport media. Most practical is to scrape the base of a new vesicle and apply the scrapings to a glass slide for DFA testing, which is sensitive and specific. PCR of vesicular fluid can also be used.
Differential:
Eye involvement is most common when accompanied by vesicles on the side or tip of the nose, meaning involvement by the nasocilliary branch of V-1 (Hutchinson’s sign). Eye involvement presents clinically with a painful red eye most commonly caused by corneal keratitis and/or uveitis (can cause chronic inflammation, scarring).
The incidence of zoster increases with age, although children who have had varicella during the first year of life (or in utero) are at increased risk of developing zoster. The incidence of zoster is less after varicella vaccination than after natural infection. Zoster in children is frequently mild, postzoster neuralgia rarely if ever occurs, and antiviral therapy is usually not needed. In a previously normal child with zoster, if the history and physical examination are normal, a laboratory search for occult immunodeficiency or malignancy is not needed.
Exposure of an immune individual to varicella or zoster should not result in zoster. In fact it boosts cellular immunity to varicella and may prevent zoster. "Outbreaks" can be explained by recognition artifact, i.e. after one case is diagnosed, it becomes more common to diagnose other cases.
PIDJ Volume 23(5) May 2004 pp 451-457 Feder, Henry M
Dermatitis herpetiformis is a severe itchy, blistering skin disease caused by gluten intolerance. DH is related to celiac disease because both are autoimmune disorders caused by gluten intolerance, but they are separate diseases. The rash usually occurs on the elbows, knees, and buttocks. Consider diagnosis in any child with FTT and atypical chronic itchy rash.
Strawberry like lesion, due to poor skin closure and healing after trauma. Remove surgically.
Seen after mycoplasma.
Lumpy, often itchy rash, quite intense in colour. Causes: drugs, SLE, idiopathic.
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