4 - PRURITUS AND NEUROCUTANEOUS DERMATOSES Flashcards
Pruritus, commonly known as itching, is a sensation exclusive to the skin. It may be defined as the sensation that produces the desire to scratch. Pruritogenic stimuli are first responded to by ______
keratinocytes, which release a variety of mediators, and fine in raepidermal C-neuron filaments.
Approximately 5% of the afferent unmyelinated C neurons respond to pruritogenic stimuli. Itch sensations in these nerve fibers are transmitted via the lateral spinothalamic tract to the brain, where a variety of foci generate both stimulatory and inhibitory responses. The sum of this complicated set of interactions appears to determine the quality and intensity of itch.
Itching may be elicited by many normally occurring stimuli, such as light touch, temperature change, and emotional stress. Chemical, mechanical, and electrical stimuli may also elicit itching. The brain may reinterpret such sensations as being painful or causative of burning or stinging sensations. A large group of neuromediators and their receptors have been identified. Some of the most important mediators are histamine and the H4 receptor, tryptase and its proteinase-activated receptor type 2, opioid peptides and the mu (µ) and kappa (κ) opioid receptors, leukotriene B4, prostaglandins such as PGE, thymic stromal lymphopoietin, acetylcholine, cytokines such as interleukin-31 (IL-31), and a variety of neuropeptides and vasoactive peptides (e.g., nerve grow h factor, substance P) and their receptors (e.g., TRPV1). Investigation is ongoing to discover the relative importance of each of these mediators and to determine the clinical circumstances under which therapeutic targeting of these molecules will lead to relief of symptoms.
What are the 4 categories of itch?
Itch has been classified into four primary categories, as follows:
• Pruritoceptive itch, initiated by skin disorders
• Neurogenic itch, generated in the central nervous system and caused by systemic disorders
• Neuropathic itch, caused by anatomic lesions of the central or peripheral nervous system
• Psychogenic itch, the type observed in parasitophobia
An overlap or mixture of these types may be causative in any individual patient.
Patterns of Itching
There are wide variations in itching from person to person, and a person may have a variation in reactions to the same stimulus. Heat will usually aggravate preexisting pruritus. Stress, absence of distractions, anxiety, and fear may all enhance itching. Itching tends to be most severe during undressing for bed.
Severe pruritus, with or without prior skin lesions, may be paroxysmal in character with a sudden onset, often severe enough to awaken the patient. It may stop instantly and completely as soon as pain is induced by scratching. However, the pleasure of scratching is so intense that the patient, despite the realization of damaging the skin, is often unable to stop short of inflicting such damage (Fig. 4.1). Itching of this distinctive type is characteristic of a select group of dermatoses: lichen simplex chronicus, atopic dermatitis, nummular eczema, dermatitis herpetiformis, neurotic excoriations, eosinophilic folliculitis, uremic pruritus, prurigo simplex, paraneoplastic itch (usually secondary to lymphoma), and prurigo nodularis. In general, only these disorders produce such intense pruritus and scratching as to induce bleeding. In individual cases, other diseases may manifest such severe symptoms.
Fig. 4.1 Severe pruritus with excoriations.
How do you manage itch?
General guidelines for therapy of the itchy patient include keeping cool and avoiding hot baths or showers and wool clothing, which is a nonspec fic irritant, as is xerosis. Many patients note itching increases after showers, when they wash with soap and then dry roughly. Using soap only in the axilla and inguinal area, patting dry and applying a moisturizer can often help prevent such exacerbations. If itching is severe, a trial of “soaking and smearing” may provide significant relief (see winter itch later in this chapter). Patients often use an ice bag or hot water to ease pruritus; however, hot water can irritate the skin, is effective only for short periods, and over time exacerbates the condition.
Relief of pruritus with topical remedies may be achieved with topical anesthetic preparations. Many contain benzocaine, which may produce contact sensitization. Pramoxine in a variety of vehicles, lidocaine 5% ointment, eutectic mixture of lidocaine and prilocaine (EMLA) ointment, and lidocaine gel are preferred anesthetics that may be beneficial in localized conditions EMLA and lidocaine may be toxic if applied to large areas. Topical antihistamines are generally not recommended, although doxepin cream may be effective for mild pruritus when used alone. Doxepin cream may cause contact allergy or a burning sensation, and somnolence may occur when doxepin is used over large areas. Topical lotions that contain menthol or camphor feel cool and improve pruritus. They may be kept in the refrigerator to enhance this soothing effect. Other lotions have specific ceramide content designed to mimic that of the normal epidermal barrier. Capsaicin, by depleting substance P, can be effective, but the burning sensation present during initial use frequently causes patients to discontinue its use. Topical steroids and calcineurin inhibitors effect a decrease in itching through their antiinflammatory action and therefore are of limited efficacy in neurogenic, psychogenic, or systemic disease–related pruritus.
Phototherapy with ultraviolet B (UVB), UVA, and psoralen plus UVA (PUVA) may be useful in a variety of dermatoses and pruritic disorders. Many oral agents are available to treat pruritus. Those most frequently used by nondermatologists are the antihis amines. First-generation H1 antihistamines, such as hydroxyzine and diphenhydramine, may be helpful in nocturnal itching, but their efficacy as antipruritics is disappointing in many disorders, except for urticaria and mastocytosis. Doxepin is an exception in that it can reduce anxiety and depression and is useful in several pruritic disorders. Sedating antihistamines should be prescribed cautiously, especially in elderly patients because of their impaired cognitive ability. The nonsedating antihistamines and H2 blockers are only effective in urticaria and mast cell disease. Opioids are involved in itch induction. In general, activation of µ-opioid receptors stimulates itch, whereas κ-opioid receptor stimulation inhibits itch perception; however, the interaction is complex. Additionally, opioid-altering agents such as naltrexone, naloxone, nalfurafine, and butorphanol have significant side effects and varying modes of delivery (intravenous, intranasal, oral). Initial reports of benefit in one condition are often followed by conflicting reports on further study. Specific recommendations in select pruritic conditions are detailed in those sections. These agents appear most useful for cholestatic pruritus. Central reduction of itch perception may be effected by anticonvulsants, such as gabapentin and pregabalin, and antidepressants, such as mirtazapine and the selective serotonin reuptake inhibi ors (SSRIs). These take 8–12 weeks to attain full onset of action Thalidomide, through a variety of direct neural effects, immunomodulatory actions, and hypnosedative effects, is also useful in select patients.
What are some of the internal causes of itching?
The most important internal causes of itching include liver disease, especially obstructive and hepatitis C (with or without evidence of jaundice or liver failure) renal failure, diabetes mellitus, hypothyroidism and hyperthyroidism, hematopoietic diseases (e.g., iron deficiency anemia, polycythemia vera), neoplastic diseases (e.g., lymphoma [especially Hodgkin disease and cutaneous T-cell lymphoma], leukemia, myeloma), internal solid-tissue malignancies, intestinal parasites, carcinoid, multiple sclerosis, acquired immunodeficiency syndrome (AIDS), connective tissue disease (particularly dermatomyositis) and neuropsychiatric diseases, especially anorex a nervosa.
The pruritus of Hodgkin disease is usually continuous and at times is accompanied by severe burning. The incidence of pruritus is 10%–30% and is the first symptom of this disease in 7% of patients. Its cause is unknown. The pruritus of leukemia, except for chronic lymphocytic leukemia, has a tendency to be less severe than in Hodgkin disease.
Internal organ cancer may be found in patients with generalized pruritus that is unexplained by skin lesions. However, no significant overall increase of malignant neoplasms can be found in patients with idiopathic pruritus. A suggested workup for chronic, generalized pruritus includes a complete history, thorough physical examination, and laboratory tests, including complete blood count (CBC) and differential; thyroid, liver, and renal panels; fasting blood glucose; hepatitis C serology; human immunodeficiency virus (HIV) antibody (if risk factors are present); urinalysis; stool for occult blood; serum protein electrophoresis; and chest x-ray evaluation. Presence of eosinophilia on the CBC is a good screen for parasitic diseases, but if the patient has been receiving systemic corticosteroids, blood eosinophilia may not be a reliable screen for parasitic diseases, and stool samples for ova and parasites should be submitted. Additional radiologic studies or specialized tests are performed as indicated by the patient’s age, history, and physical findings. A biopsy for direct immunofluorescence is occasionally helpful to detect dermatitis herpetiformis or pemphigoid.
Treatment of the itch associated with some of these internal conditions is discussed later in this chapter or under those specific diseases in other chapters; however, in other conditions listed previously treatment of the underlying disease state (e.g., treating the cancer, replacing thyroid hormone in hypothyroidism) causes relief of the pruritus. Be aware that disease specific therapies can exacerbate itching during treatment, for instance in cancer patients treated with biologic agents such as the anti EGFR monocolonal antibiodies.
What is the most common systemic cause of pruritus?
Fig. 4.2 (A) Acquired perforating dermatosis of uremia.
Chronic kidney disease (CKD)
20%–80% of patients with chronic renal failure have itching. The pruritus is often generalized, intractable, and severe; however, dialysis-associated pruritus may be episodic, mild, or localized to the dialysis catheter site, face, or legs.
The mechanism of pruritus associated with CKD is multifactorial. Xerosis, secondary hyperparathyroidism, increased serum histamine levels, hypervitaminosis A, iron deficiency anemia, and neuropathy have been implicated. Complications such as acquired perforating disease, lichen simplex chronicus, and prurigo nodularis may develop and contribute to the degree and severity of pruritus (Fig. 4.2).
Fig 4.2 Close-up view of Acquired perforating dermatosis of uremia.
Management of pruritus scondary to CKD?
Many patients have concomitant xerosis, and aggressive use of emollients, including “soaking and smearing” (see winter itch later in this chapter), may help. A trial of γ-linolenic acid cream twice daily was effective, as was one using baby oil. Gabapentin given three times weekly at the end of hemodialysis sessions can be effective, but its renal excretion is decreased in CKD, so a low initial dose of 100 mg after each session with slow upward titration is recommended. A mainstay of CKD-associated pruritus has been narrow-band (NB) UVB phototherapy, but a randomized controlled trial (RCT) failed to confirm its efficacy. Broad-band UVB may be best in the CKD patient. Naltrexone, topical tacrolimus, and ondansetron also were reported to be useful in initial trials, but subsequent studies indicated these agents are ineffective. Nalfurafine, 5 µg once daily after supper, has demonstrated improvement and was relatively well tolerated over a 1-year study. Thalidomide, intranasal butorphanol, and intravenous lidocaine are less practical options. Patients on peritoneal dialysis have a lower severity of pruritus than those on hemodialysis. Renal transplantation will eliminate pruritus.
What causes biliary pruritus?
Chronic liver disease with obstructive jaundice may cause severe generalized pruritus, and 20%–50% of patients with jaundice have pruritus. Intrahepatic cholestasis of pregnancy, primary sclerosing cholangitis, and hereditary cholestatic diseases such as Alagille syndrome all have pruritus in common. Another disease, primary biliary cirrhosis, is discussed separately next because of its many other cutaneous manifestations. Hepatitis C may be associated with pruritus as well.
Itching of biliary disease is probably caused by central mechanisms. The pathophysiology is not well understood, but it appears that lysophosphatidic acid, formed by the action of the enzyme autotaxin on lysophosphatidylcholine, is central. The serum conjugated bile acid levels do not correlate with the severity of pruritus, and the theory invoking endogenous opioids as the main cause has not been upheld.
Management of biliary pruritus
Pruritus of chronic cholestatic liver disease is improved with cholestyramine, 4 to 16 g daily. Rifampin, 150 to 300 mg/day, may be effective but should be used with caution because it may cause hepatitis. Naltrexone, up to 50 mg/day, is useful but has significant side effects. If used, naltrexone should be started at 1 tablet (12.5 mg) and increased by 1 tablet every 3 to 7 days 4 4 until pruritus improves. Sertraline, 75 to 100 mg/day, is another option. UVB phototherapy was effective in a small case series. Ursodeoxycholic acid is effective for the pruritus in intrahepatic cholestasis of pregnancy, but not for the itching from other causes. Liver transplantation is the definitive treatment for end-stage disease and provides dramatic relief from the severe pruritus
Pruritus in Primary Biliary Cirrhosis
Fig. 4.3 Primary biliary cirrhosis with plane xanthomas.
Primary biliary cirrhosis occurs almost exclusively in women older than 30. Itching may begin insidiously and may be the presenting symptom in a quarter to half of patients. With time, extreme pruritus develops in almost 80% of patients. This almost intolerable itching is accompanied by jaundice and a striking melanotic hyperpigmentation of the entire skin; the patient may turn almost black, except for a hypopigmented “butterfly” area in the upper back. Eruptive xanthomas, planar xanthomas of the palms (Fig. 4.3), xanthelasma, and tuberous xanthomas over the joints may be seen.
Dark urine, steatorrhea, and osteoporosis occur frequently. Serum bilirubin, alkaline phosphatase, serum ceruloplasmin, serum hyalurona e, and cholesterol values are increased. The antimitochondrial antibody test is positive. The disease is usually relentlessly progressive with the development of hepatic failure. Several cases have been accompanied by scleroderma.
Pruritus in Polycythemia vera
More than one third of patients with polycythemia vera report pruritus; it is usually induced by temperature changes or several minutes after bathing. The cause is unknown.
Aspirin has been shown to provide immediate relief from itching; however, there is a risk of hemorrhagic complications. PUVA and NB UVB are also effective. A marked improvement is noted after an average of six treatments, with complete remission often occurring in 2–10 weeks. Paroxetine, 20 mg/day, produced clearing or near-complete clearing in a series of nine patients. Interferon (IFN) alpha 2 has been shown to be effective for treating the underlying disease and associated pruritus.
characterized by pruritus that usually first manifests and is most severe on the legs and arms. Extension to the body is common; however, the face, scalp, groin, axillae, palms, and soles are spared. The skin is dry with fine flakes (Fig. 4.4).
Fig 4.4 Winter itch.
Asteatotic eczema, eczema craquelé, and xerotic eczema are other names for this pruritic condition.
The pretibial regions are particularly suscep ible and may develop eczema craquelé, exhibiting fine cracks in the eczematous area that resemble the cracks in old porcelain dishes.
Frequent and lengthy bathing with plenty of soap during the winter is the most frequent cause. This is especially prevalent in elderly persons, whose skin has a decreased rate of repair of the epidermal water barrier and whose sebaceous glands are less productive. Low humidity in overheated rooms during cold weather contributes to this condition In a study of 584 elderly individuals,
the prevalence of asteatosis (28.9%) was second only to seborrheic dermatitis as the most common finding.
Treatment consists of educating the patient on using soap only in the axillae and inguinal area and lubricating the skin with emollients mmediately after showering. Preparations containing lactic acid or urea applied after bathing are helpful in some patients but may cause irritation and may worsen itching in patients with erythema and eczema.
For those with more severe symptoms, long-standing disease, or a significant inflammatory component, a regimen referred to as “soaking and smearing” is dramatically effective. The patient soaks in a tub of plain water at a comfortable temperature for 20 minutes before bedtime. Immediately on exiting the tub, without drying, triamcinolone, 0.025%–0.1% ointment, is applied to the wet skin. This will trap the moisture, lubricate the skin, and allow for excellent penetration of the steroid component. An old pair of pajamas is then donned, and the patient will note relief even on the first night. The nighttime soaks are repeated for several nights, after which the ointment alone suffices, with the maintenance therapy of limiting soap use to the axillae and groin, and moisturization after showering. Plain petrolatum may be used as the lubricant after the soaking if simple dryness without inflammation is present. Folliculitis may complicate this therapy.
Pruritus Ani
Pruritus is often centered on the anal or genital area (less frequently in both), with minimal or no pruritus elsewhere. Anal neurodermatitis is characterized by paroxysms of violent itching, when the patient may tear at the affected area until bleeding is induced. Manifestations are identical to lichen simplex chronicus elsewhere on the body. Specific etiologic factors should always be sought and generally can be classified as dermatologic disease, local irritants (which may coexist with colorectal and anal causes), and infectious agents.
Allergic contact dermatitis is a common dermatologic cause or secondary complication of pruritus ani. It occurs from various medicaments, fragrance in toilet tissue, or preservatives in moist toilet tissue, with one study reporting 18 of 40 consecutive patients being patch test positive. Seborrheic dermatitis, psoriasis, lichen planus, lichen sclerosis, and atopic dermatitis all may cause perianal itching, and an examination of other classic sites of involvement with these conditions should be carefully undertaken. Extramammary Paget disease and Bowen disease, although not often itchy, may be present and will not improve with therapy. Biopsy of resistant dermatitic-appearing skin should be done in nonresponsive pruritus ani.
Irritant contact dermatitis from gastrointestinal contents, such as hot spices or cathartics, or failure to cleanse the area adequately after bowel movements may be causal. Anatomic factors may lead to leakage of rectal mucus on to perianal skin and thus promote irritation. Physical changes such as hemorrhoids, anal tags, fissures, and fistulas may aggravate or produce pruritus.
Mycotic pruritus ani is characterized by fissures and a white, sodden epidermis. Scrapings are examined directly with potassium hydroxide mounts, and cultures will usually reveal Candida albicans, Epidermophyton floccosum, or Trichophyton rubrum. Other sites of fungal infection, such as the groin, toes, and nails, should also be investigated. Erythrasma in the groin and perianal regions may also occasionally produce pruritus. The diagnosis is established by coral red fluorescence under the Wood’s light. β-Hemolytic streptococcal infections have also been implicated, especially in young children. The use of tetracyclines may cause pruritus ani, most often in women, by inducing candidiasis. Diabetic patients are susceptible to perianal candidiasis.
Pinworm infestations may cause pruritus ani, especially in children and sometimes in their parents. Nocturnal pruritus is most prevalent. Other intestinal parasites, such as Taenia solium, T. saginata, amebiasis, and Strongyloides stercoralis, may produce pruritus. Pediculosis pubis may cause anal itching; however, attention is focused by the patient on the pubic area, where itching is most severe. Scabies may be causative but often will also involve the finger webs, wrists, axillae, areolae, and genitalia.
Lumbosacral radiculopathy also may be present with pruritus ani, as assessed by radiographs and nerve conduction studies; paravertebral blockade may help these patients.
Treatment of pruritus ani
Meticulous toilet care should be followed, no matter what the cause of the itching. After defecation, the anal area should be cleansed whenever possible, washed with mild soap and water. Cleansing with wet toilet tissue is advisable in all cases. Medicated cleansing pads (Tucks) should be used regularly. A variety of moist toilet tissue products are now available. Contact allergy to preservatives in these products is occasionally a problem. An emollient lotion (Balneol) is helpful for cleansing without producing irritation.
Once the etiologic agent has been identified, a rational and effective treatment regimen may be started. Topical corticosteroids are effective for most noninfectious types of pruritus ani; however, use of topical tacrolimus ointment will frequently suffice and is safer. Pramoxine, a nonsteroidal topical anesthetic, is also often effective, especially in a lotion form combined with hydrocortisone. In pruritus ani, as well as in pruritus scroti and vulvae, it is sometimes best to discontinue all topical medications and treat with plain water sitz baths at night, followed immediately by plain petrolatum applied over wet skin. This soothes the area, provides a barrier, and eliminates contact with potential allergens and irritants.
The scrotum of an adult is a susceptible site for circumscribed neurodermatitis (lichen simplex chronicus) (Fig. 4.5).
Fig. 4.5 Pruritus scroti
Psychogenic pruritus is probably the most frequent type of itching seen. Why it preferentially affects the scrotum, or in women the vulva (see pruritus vulvae), is unclear. Lichenification may result, can be extreme, and may persist for many years despite intensive therapy.
Infectious conditions may complicate or cause pruritus on the scrotum but are less common than idiopathic scrotal pruritus. Fungal infections, except candidiasis, usually spare the scrotum. When candidal infection affects the scrotum, burning rather than pruritus is frequently the primary symptom. The scrotum is eroded, weepy, or crusted. The scrotum may be affected to a lesser degree in cases of pruritus ani, but this pruritus usually affects the midline, extending from the anus along the midline to the base of the scrotum, rather than the dependent surfaces of the scrotum, where pruritus scroti usually occurs Scrotal pruritus may be associated with allergic contact dermatitis from topical medications, including steroidal agents.
Management of pruritus scroti
Topical corticosteroids are the mainstay of treatment, but caution should be exercised. The “addicted scrotum syndrome” may be caused by the use of high-potency topical steroidal agents As with facial skin, after attempts to wean patients off the steroid, severe burning and redness may occur. Although usually seen after chronic use, this may occur even with short-term high-potency steroids. The scrotum is frequently in contact with inner thigh skin, producing areas of occlusion, which increases the penetration of topical steroid agents. Topical tacrolimus ointment is useful in overcoming the effects of overuse of potent topical steroids. Another alternative is gradual tapering to less potent corticosteroids. Other useful nonsteroidal alternatives include topical pramoxine, doxepin, and simple petrolatum, which is applied after a sitz bath as described for pruritus ani.
The vulva is a common site for pruritus of different causes. It is the counterpart of pruritus scroti.
Fig. 4.6 Lichen simplex chronicus of the vulva.
Pruritus Vulvae
In a prospective series of 141 women with chronic vulvar symptoms, he most common causes were unspecified dermatitis (54%), lichen sclerosus (13%), chronic vulvovaginal candidiasis (10%), dysesthetic vulvodynia (9%), and psoriasis (5%). In prepubertal children, such itching is most frequently irritant in nature, and girls generally benefit from education about improved hygienic measures.
Vaginal candidiasis is a frequent cause of pruritus vulvae. This is true especially during pregnancy and when oral antibiotics are taken. The inguinal, perineal, and perianal areas may be affected. Microscopic examination for Candida albicans and cultures for fungus should be performed Trichomonas vaginalis infection may cause vulvar pruritus. For the detection of T. vaginalis, examination of vaginal secretions is often diagnostic. The organism is recognized by its motility, size (somewhat larger than a leukocyte), and piriform shape.
Contact dermatitis from sanitary pads, contraceptives, douche solutions, fragrance, preservatives especially in moist towelettes, colophony, benzocaine, corticosteroids, and a partner’s condoms may account for vulvar pruritus. Urinary incontinence should also be considered. Lichen sclerosus is another frequent cause of pruritus in the genital area in middle-age and elderly women. Lichen planus may involve the vulva, resulting in pruritus and mucosal changes, including erosions and ulcerations, resorption of the labia minora, and atrophy.
When burning rather than itching predominates, the patient should be evaluated for signs of sensory neuropathy.
Treatment of pruritus vulvae
Candidiasis and Trichomonas treatments are discussed in Chapters 15 and 20, respectively. Lichen sclerosus responds best to pulsed dosing of high-potency topical steroids or to topical tacrolimus or pimecrolimus. Topical steroidal agents and topical tacrolimus may be used to treat psychogenic pruritus or irritant or allergic reactions. The use of silk fabric underwear may limit irritation. Patch testing will assist in identifying the inciting allergen. Highpotency topical steroids are effective in treating lichen planus, but other options are also available (see Chapter 12). Topical lidocaine, topical pramoxine, or an oral tricyclic antidepressant (TCA) may be helpful in select cases. Phototherapy using a comb light device may be effective. Any chronic skin disease that does not respond to therapy should prompt a biopsy.
consists of one or two intensely itchy spots in clinically normal skin, sometimes followed by the appearance of seborrheic keratoses at exactly the same site.
Puncta Pruritica (Itchy Points)
Curettage, cryosurgery, punch biopsy, or botulinum toxin A injection of the itchy points may cure the condition.
itching evoked by contact with water of any temperature.
Aquagenic Pruritus
Most patients experience severe, prickling discomfort within minutes of exposure to water or on cessation of exposure to water. There are two groups of patients: about one third consist of an older, primarily male population who have polycythemia vera, hypereosinophilic syndrome, or myelodysplastic syndrome, and two thirds are younger women who develop aquagenic pruritus as young adults and who have no known underlying disease and may have a family history of similar symptoms.
Aquagenic pruritus must be distinguished from xerosis as water may be perceived as an irritant in severely dry skin, and in these cases an initial trial of “soaking and smearing,” as previously described for winter itch, is recommended. Treatment options for aquagenic pruritus include the use of antihistamines, sodium bicarbonate dissolved in bath water, propranolol, atenolol, SSRIs, acetylsalicylic acid (ASA, aspirin), pregabalin, montelukast, and NB UVB or PUVA phototherapy. One patient found tight-fitting clothing settled the symptoms after only 5 minutes.
widespread burning pain that lasted 15–45 minutes after water exposure, calling this reaction ______
aquadynia and considering the disorder a variant of aquagenic pruritus. Clonidine and propranolol seemed to provide some relief.
Scalp Pruritus
Pruritus of the scalp, especially in elderly persons, is rather common. Lack of excoriations, scaling, or erythema excludes inflammatory causes of scalp pruritus such as seborrheic dermatitis, psoriasis, dermatomyositis, or lichen simplex chronicus. Most such cases remain are neuropathic or idiopathic, but some represent chronic folliculitis. Treatment with topical tar shampoos, salicylic acid shampoos, corticosteroid topical gels, mousse, shampoos, and liquids can be helpful. In patients who have severe scalp pruritus with localized itch, an intralesional injection of corticosteroid suspension may provide relief. Minocycline or oral antihistamines may be helpful. In other patients, low doses of antidepressants, such as doxepin, are useful.
a rare dermatosis of unknown cause c acterized by the sudden onset of erythematous papules or vesicles that leave reticulated hyperpigmentation when they heal (Fig. 4.7).
Fig 4 7 Prurigo pigmentosa. (Courtesy Department of Dermatology, Keio University School of Medicine, Tokyo, Japan.)
The condition mainly affects Japanese, although numerous cases have been reported in Caucasians. Women outnumber men 2 : 1. The mean age of onset is 25. It is associated with weight loss, dieting, anorexia, post bariatric surgery, pregnancy, diabetes, and ketonuria. It is exacerbated by heat, sweating, and friction and thus occurs most often in the winter and spring. The areas most frequently involved are the upper back, nape, clavicular region, and chest. Mucous membranes are spared. Histology of early lesions shows neutrophils in the dermal papillae and epidermis. Following this, a lichenoid dermatitis with variable psoriasiform hyperplasia occurs Direct immunofluorescence yields negative findings. The cause is unknown. Minocycline, 100–200 mg/day, is the treatment of choice. Dapsone and alteration of the diet are also effective; topical steroids are not effective. Recurrence and exacerbations are common.
Also known as circumscribed neurodermatitis, _______ results from long-term chronic rubbing and scratching, more vigorously than a normal pain threshold would permit, with the skin becoming thickened and leathery.
Fig. 4.8 Lichen simplex chronicus.
The normal markings of the skin become exaggerated (Fig. 4.8), so that the striae form a crisscross pattern, producing a mosaic in between composed of flat topped, shiny, smooth quadrilateral facets. This change, known as lichenification, may originate on seemingly normal skin or may develop on skin that is the site of another disease, such as atopic or allergic contact dermatitis or ringworm. Such underlying etiologies should be sought and, if found, treated specifically. Paroxysmal pruritus is the main symptom Circumscribed, lichenified pruritic patches may develop on any part of the body; however, lichen simplex chronicus has a
predilection for the back and sides of the neck, the scalp, the upper eyelid, the orifice of one or both ears, the palm, soles, or often the wrist and ankle flexures. The vulva, scrotum, and anal areas are common sites, although the genital and anal areas are seldom involved at the same time. The eruption may be papular, resembling lichen planus; and in other cases the patches are excoriated, slightly scaly or moist, and rarely, nodular. Persistent rubbing of the shins or upper back may result in dermal deposits of amyloid and the subsequent development of lichen or macular amyloidosis, respectively.
The onset of this dermatosis is usually gradual and insidious. Chronic scratching of a localized area may be a response to an inciting dermatitis; however, scratching of the localized site continues long after the original insult and becomes a habit. It may be associated with anxiety disorders and in depressed patients, with erectile dysfunction.
A disease with multiple itchy nodules mainly on the extremities (Fig. 4.9), especially on the anterior surfaces of the thighs and legs.
Fig. 4.9 Prurigo nodularis. (Courtesy Debabrata Bandyopadhyay, MD.)
A linear arrangement is common. The individual lesions are pea sized or larger, firm, and erythematous or brownish. When fully developed, they become verrucous or fissured. The course of the disease is chronic, and the lesions evolve slowly. Itching is severe but usually confined to the lesions themselves. Bouts of extreme pruritus often occur when these patients are under stress. Prurigo nodularis is one of the disorders in which the pruritus is characteristically paroxysmal: intermittent, unbearably severe and relieved only by scratching to the point of damaging the skin, usually inducing bleeding and often scarring.
The cause of prurigo nodularis is unknown; multiple factors may contribute, including atopic dermatitis, hepatic diseases (including hepatitis C), HIV disease, pregnancy, renal failure, lymphoproliferative disease, stress, and insect bites. Pemphigoid nodularis may be confused with prurigo nodularis clinically.
The histologic findings are those of compact hyperkeratosis, irregular acanthosis, multinucleated keratinocytes, and a perivascular mononuclear cell infiltrate in the dermis. Dermal collagen may be increased, especially in the dermal papillae, and subepidermal fibrin may be seen, both evidence of excoriation. In cases associated with renal failure, transepidermal elimination of degenerated collagen may be found.
Skin Signs of Psychiatric Illness
Fig. 4.10 Onychophagia. (Courtesy Curt Samlaska, MD.)
The skin is a frequent target for the release of emotional tension. Some of the signs described here may become repetitive compulsions that impair normal life functions and may be manifestations of an obsessive-compulsive disorder. Self-injury by prolonged, compulsive repetitious acts may produce various mutilations, depending on the act and site of injury.
Self-biting may be manifested by biting the nails (onychophagia) or recurrent manipulation of components of the nail unit (onychotillomania) (Fig. 4.10), skin (most frequently the forearms, hands, and fingers), and lip. Dermatophagia is a habit or compulsion, conscious or subconscious. Bumping of the head produces lacerations and contusions, which may be so severe as to produce cranial defects and life-threatening complications. Compulsive repetitive handwashing may produce an irritant dermatitis of the hands (Fig. 4.11).
Fig. 4.11 Irritant dermatitis from chronic handwashing.
Bulimia, with its self-induced vomiting, results in Russell sign—crusted papules on the dorsum of the dominant hand from cuts by the teeth. Clenching of the hand produces swelling and ecchymosis of the fingertips and subungual hemorrhage.
Self-inflicted lacerations may be of suicidal intent Lip licking produces increased salivation and thickening of the lips. Eventually, the perioral area becomes red and produces a distinctive picture resembl ng the exaggerated mouth makeup of a clown. Pressure produced by binding the waistline tightly with a cord will eventually lead to atrophy of the subcutaneous tissue.
Psychopharmacologic agents, especially the newer atypical antipsychotic agents, and behavioral therapy alone or in combination with these agents are the treatments of choice.
Many persons have u scious compulsive habits of picking at themselves, and at times the tendency is so persistent and pronounced that excoriations of the skin result.
Excoriation Disorder AKA also called psychogenic excoriations, neurotic excoriations or skin picking disorder
The lesions are caused by picking, digging, or scraping and usually occur on parts readily accessible to the hands. These patients admit their actions induce the lesions but cannot control their behavior.
The excavations may be superficial or deep and are of en linear. The bases of the ulcers are clean or covered with a scab. Righthanded persons tend to produce lesions on their left side and left-handed persons on their right side. There is evidence of past healed lesions, usually with linear scars, or rounded hyperpigmented or hypopigmented lesions, in the area of the active excoriations. The face, upper arms, and upper back are common sites for these excoriations (Fig. 4.12). Sometimes the focus is on acne lesions, producing acne excoriée.
Fig. 4.12 Psychogenic excoriations. (Courtesy Steven Binnick, MD.)
Most of these patients are otherwise healthy adults leading normal lives. The organic differential diagnosis is vast and includes any condition that may manifest with excoriations. The most common psychopathologies associated with neurotic excoriations are depression, obsessive-compulsive disorder, and anxiety
The treatment of choice is doxepin because of its antidepressant and antipruritic effects; doses are slowly increased to 100 mg or higher, if tolerated. Many alternatives to doxepin may be indicated, especially in hose affected by an obsessive-compulsive component. N-acetylcysteine 1200 to 3000 mg/day is safe and tolerable option, which is now being studied in many psychodermatologic conditions. It has been shown to be effective in this excoriation disorder. Treatment is difficult, often requiring a combined psychiatric and pharmacologic intervention. It is important to establish a constructive patient-therapist alliance. Training in diversion strategies during “scratching episodes” may be helpful. An attempt should be made to identify specific conflicts or stressors preceding onset. The therapist should concentrate on systematic training directed at the behavioral reaction pattern. There should be support and advice given with regard to the patient’s social situation and interpersonal relations.
has an unconscious goal of gaining attention and assuming the sick patient role
Fig. 4.13 Factitial ulcers and scarring.
Dermatitis Artefacta
Most patients are adults in midlife, with women affected three times more often than men. The vast majority have multiple lesions and are unemployed or on sick leave. These skin lesions are provoked by mechanical means or by the application or injection of chemical irritants and caustics. These patients often have a “hollow” history, unable to detail how the lesions appeared or evolved. The lesions may simulate other dermatoses but usually have a distinctive, geometric, bizarre appearance (Fig. 4.13), often with a shape and arrangement not encountered in other disorders. The lesions are generally distributed on parts easily reached by the hands, tend to be linear and arranged regularly and symmetrically, and are rarely seen on the dominant hand.
When chemicals are used, red streaks or guttate marks are often seen beneath the principal patch, where drops of the chemical have accidentally run or fallen on the skin. According to the manner of production, the lesions may be erythematous, vesicular, bullous, ulcerative, or gangrenous. The more common agents of destruction used are the fingernails, pointed instruments, hot metal, chemicals (e g., carbolic, nitric, or acetic acid), caustic potash or soda, turpentine, table salt, urine, and feces. The lesions are likely to appear in crops. At times the only sign may be the indefinitely delayed healing of an operative wound, which is purposely kept open by the patient. Tight cords or clothing tied around an arm or leg may produce factitious lymphedema, which may be mistaken for postphlebitic syndrome or nerve injury, as well as other forms of chronic lymphedema.
Subcutaneous emphysema, manifesting as cutaneous crepitations, may be factitial in origin. Recurrent migratory subcutaneous emphysema involving the extremities, neck, chest, or face can be induced through injections of air into tissue with a needle and syringe. Circular pockets and bilateral involvement without physical findings, indicating contiguous spread from a single source, suggest a factitial origin. Puncturing the buccal mucosa through to facial skin with a needle and puffing out the cheeks can produce alarming
results. Neck and shoulder crepitation is also a complication in manic patients that results from hyperventilation and breath holding
The organic differential diagnosis depends on the cutaneous signs manifested, such as gas gangrene for patients with factitious subcutaneous emphysema and the various forms of lymphedema for factitious lymphedema. A subset of these patients have Munchausen syndrome. They tend to cause lesions that closely simulate known conditions, and they create an intricate, often fantastic story surrounding the problem. Admissions to the hospital with extensive workup of en result. Parents may induce lesions on their child to gain attention, so-called Munchausen by proxy, which is really child abuse. Considerations for psychopathology in dermatitis artefacta include borderline personality disorders and psychosis.
Proof of diagnosis is sometimes difficult. Occlusive dressings may be necessary to protect the lesions from ready access by the patient. It is usually best not to reveal any suspicion of the cause to the patient and to establish the diagnosis definitively without the patient’s knowledge. If the patient is hospitalized, a resourceful, cooperative nurse may be useful in helping to establish the diagnosis. When injection of foreign material is suspected, examination of biopsy material by spectroscopy may reveal talc or other foreign material. Additionally epidermal multinucleated keratinocytes may be present as a clue.
Treatment should ideally involve psychotherapy, but typically the patient promptly rejects the suggestion and goes to another physician to seek a new round of treatment. It is best for the dermatologist to maintain a close relationship with the patient and provide symptomatic therapy and nonjudgmental support. SSRIs may address associated depression and anxiety. Very-low-dose atypical antipsychotics may also be added, if needed Consultation with an experienced psychiatrist is prudent.
characterized by an abnormal urge to pull out the hair
Trichotillomania (trichotillosis or hair pulling disorder)
The sites involved are generally the frontal region of the scalp, eyebrows, eyelashes, and the beard. The classic presentation is the “Friar Tuck” form of vertex and crown alopecia. There are irregular areas of hair loss, which may be linear or bizarrely shaped. Infrequently, adults may pull out pubic hair. Hairs are broken and show differences in length (Fig. 4.14). The pulled hair may be ingested, and occasionally the trichobezoar will cause obstruction. When the tail extends from the main mass in the stomach to the small or large intestine, Rapunzel syndrome is the diagnosis. The nails may show evidence of onychophagy (nail biting), but no pits are present. The disease is seven times more common in children than in adults, and girls are affected 2.5 times more often than boys.
Trichotillomania often develops in the setting of psychosocial stress in the family, which may involve school problems, sibling rivalry, moving to a new house, hospitalization of a parent, or a disturbed parent-child relationship.
Encompassing the descriptors reflex sympathetic dystrophy, causalgia, neuropathic pain, and Sudek syndrome and is characterized by burning pain, h esthesia, and trophic disturbances resulting from injury to a peripheral nerve.
Fig. 4.15 Complex regional pain syndrome.
The continuing pain is disproportionate to the injury, which may have been a crush injury, laceration, fracture, hypothermia, sprain, burn, or surgery. It usually occurs in one of the upper extremit es, although leg involvement is also common. The characteristic symptom is burning pain aggravated by movement or friction The skin of the involved extremity becomes shiny, cold, and atrophic and may perspire profusely. Additional cutaneous manifestations include bullae, erosions, edema, telangiectases, hyperpigmentation, ulcerations, and brownish red patches with linear fissures (Fig. 4.15).
The intensity of the pain in CRPS patients varies from trivial burning to a state of torture accompanied by extreme hyperesthesia and frequently hyperhidrosis. Not only is the part subject to an intense burning sensation, but also a touch of the finger also causes exquisite pain. Exposure to the air is avoided with scrupulous care, and the patient walks carefully, carrying the limb tenderly with the sound hand. Patients are tremulous and apprehensive, and they keep the hand constantly wet, finding relief in the moisture rather than in the temperature of the application. A condition resembling permanent chilblains or even trophic ulcers may be present.
The syndrome usually begins with severe, localized, burning pain. focal edema, muscle spasm, stiffness or restricted mobility, and vasospasm affecting skin color and temperature. These may be followed by a diffusion of the pain and edema, diminished hair growth, brittle nails, joint thickening, and onset of muscle atrophy. Finally, irreversible trophic changes, intractable pain involving the entire limb, flexor contractures, marked atrophy of the muscles, severe limitation in joint and limb mobility, and severe osteoporosis result.
Not all patients will have all the features of CRPS, and an early diagnosis improves the chance of cure. The four major components are categorized as sensory, vasomotor, sudomotor/ edema, and motor/trophic. Signs pertaining to at least two of these categories and symptoms relating to three are necessary to meet the Budapest diagnostic criteria. A three phase technetium bone scan is helpful in confirming the diagnosis of CRPS.
Consultation with a neurologist or an anesthesiologist specializing in pain is advisable. Osteoporosis is a frequent complication, and studies using pamidronate, a powerful inhibitor of bone absorption, have been shown to improve symptoms of pain, tenderness, and swelling significantly. Pain relief which allows for physical mobilization and massage is helpful. Additionally psychological intervention with patients, their families, and caregivers is important as they often require ongoing support, education, and counseling.
Also known as neuropathic ulceration or perforating ulcer mal perforans is a chronic ulcerative disease seen on the sole or hand in conditions that result in loss of pain sensation at a site of constant trauma (Fig. 4.16).
Fig. 4.16 Neuropathic ulcer of the hand in a diabetic patient.
Mal Perforans Pedis
The primary cause lies in the p terolateral tracts of the cord (in arteriosclerosis and tabes dorsalis), lateral trac s (in syringomyelia), or peripheral nerves (in diabetes or Hansen disease).
In most patients, mal perforans begins as a circumscribed hyperkeratosis, usually on the ball of the foot. This lesion becomes soft, moist, and malodorous and later exudes a thin, purulent discharge. A slough slowly develops, and an indolent necrotic ulcer is left that lasts indefinitely. Whereas the neuropathy renders the ulceration painless and walking continues, plantar ulcers in this condition have a surrounding thick callus. Deeper perforation and secondary infection often lead to osteomyelitis of the metatarsal or tarsal bones.
Treatment consists of relief of pressure on the ulcer through use of a total-contact cast and debridement of the surrounding callosity. Removable off-loading devices were found to be significantly less effective in a systematic review and meta-analysis. Administration of local and systemic antibiotics is sometimes helpful.
