Table of Contents   This Chapter   All Chapters

FUNCTIONAL DISORDERS AND DERMATOSES OF SKIN APPENDAGES

Eccrine and apocrine glands

Hyperhidrosis (increased sweating)

Patterns and etiology

Increased sweating is a relatively common complaint and rarely has an identifiable cause. It may be divided by the site affected.

    Generalized hyperhidrosis is a somewhat subjective symptom that may be related to anxiety or emotional stimuli, but also occurs as a feature of thyrotoxicosis, menopause, diabetes, heart failure, and brain lesions. Other symptoms and associations need to be considered. For example, hyperhidrosis with hypertension, headache, and tachycardia suggests pheochromocytoma, whereas episodic hyperhidrosis with hypothermia suggests a hypothalamic lesion. Increased sweating also occurs in POEMS syndrome (polyneuropathy, organomegaly, endocrine disturbance, monoclonal gammopathy, and skin changes such as hyperpigmentation). Night sweats occur in tuberculosis and other chronic infections, lymphoma, diabetes, dumping syndrome, pheochromocytoma, and carcinoid syndrome.

    Axillary hyperhidrosis in isolation, or with palm and sole hyperhidrosis, is usually emotional, and investigations for an underlying cause are unlikely to be helpful in the absence of other symptoms.

    Palm and sole hyperhidrosis may occur in some patients with vascular problems in the limbs (such as Raynaud phenomenon, erythromelalgia,
or those locally related to arteriovenous fistulas), but again is mainly emotionally triggered. Emotionally provoked palmoplantar hyperhidrosis typically stops at night or after sedation (as does axillary hyperhidrosis, but this may be thermally triggered as well). Hyperhidrosis of palms, in particular, can be very disabling in a small proportion of patients who find it difficult to prevent paperwork from being spoiled by palmar sweating (Figs 23.1 and 23.2) or who need to shake hands during their occupation.

    Hyperhidrosis of the head and neck occurs in patients with cervical spine lesions, such as injuries or syringomyelia (Figs 23.3 and 23.4). Sweating may be triggered by orthostatic hypotension or other autonomic stimuli, such as bladder distention or bowel symptoms. In such patients, sweating may be associated with tachycardia, hypertension, and vasodilatation. Several rare neurologic conditions may be associated with localized hyperhidrosis.

    Unilateral upper limb or head and neck hyperhidrosis is a rare feature of intrathoracic neoplasia.

    Gustatory sweating affects the head and neck, and is triggered by eating. This may be idiopathic, but also occurs due to sympathetic trunk damage (surgical or tumor) or in patients with autonomic neuropathy due to diabetes. The most common type is localized sweating affecting the distribution of the auriculotemporal nerve that occurs after parotid surgery and is known as Frey syndrome; this is due to aberrant nerve regeneration after injury, such that parasympathetic fibers migrate into the cutaneous sympathetic nerves that supply the sweat glands.

Fig 23.1  Profuse palmar hyperhidrosis may be a disabling condition. It is not only socially embarrassing, but some patients may find it difficult to hold pens or to avoid smudging paperwork.

Fig 23.2  In some cases, hyperhidrosis may be sufficiently severe that patients complain of dripping from hands, feet, or axillae. This can also occur on the face due to cervical spine injury or in Frey syndrome.

    Transient increased sweating causing skin lesions (miliaria) is discussed later.

Treatment

When an underlying cause can be identified, this may be correctable. Otherwise, treatment is symptomatic and needs to take into account potential adverse effects and morbidity.

    Localized axillary hyperhidrosis can usually be controlled with aluminum chloride antiperspirants, which should be applied at night when emotional sweating does not occur. This may also be useful for palms and soles.

    Tap water iontophoresis is helpful for palms and soles but technically difficult for other body sites, as the affected parts need to be immersed. The technique involves passing a low-strength direct current (15–30mA) through the body between two shallow trays of water in which the two hands (or feet) are immersed. This technique can also be used in conjunction with anticholinergic drug solutions, such as glycopyrronium bromide, but may then cause transient visual blurring or dry mouth.

Fig 23.4  Hospital observation chart of the patient shown in Figure 23.3. Spikes of tachycardia and blood pressure accompany the bouts of sweating (arrows), in keeping with an autonomic nervous system lesion.

    Systemic anticholinergic agents such as propantheline may be useful, especially for generalized hyperhidrosis or gustatory sweating affecting the head and neck. However, they have inevitable anticholinergic side effects, which may limit therapy. Other drugs, such as clonidine or tricyclics, may be useful in some instances.

    Surgical techniques include excision or liposuction of axillary skin, but excision is limited by the tightness of the subsequent wound. Endoscopic intrathoracic sympathectomy is sometimes used for disabling palmar hyperhidrosis, but is not without morbidity and carries a risk of compensatory hyperhidrosis at other sites, or gustatory hyperhidrosis.

    Injections of botulinum toxin in minute amounts into the skin (typically 1–5U per 1–2cm 2 surface area) have been used with good results for gustatory, axillary, and palmar hyperhidrosis, but need to be repeated every 4–9 months in most cases; for the palms, nerve block anesthesia may be required to administer the injections.

PRACTICE POINTS

Decreased sweating

This is not usually perceived as a problem, unless it is extreme. A few disorders warrant specific mention.

Anhidrotic (hypohidrotic) ectodermal dysplasia

This X-linked condition is the most important dermatologic disorder in which hypohidrosis is a feature. Affected patients have dry skin with eczematous areas, hyperkeratosis of palms and soles, conical teeth, sparse hair and eyebrows, and a saddle nose. The ability to sweat may be minimal and carries a risk of hyperthermia, especially during febrile illnesses or in the summer months. Female carriers exhibit partial features of the disorder.

Ross syndrome

This condition is the association of segmental anhidrosis, loss of deep tendon reflexes, and a poorly reactive (Holmes–Adie) pupil. This condition is more common than the small number of reported cases would suggest, and recognition of anhidrotic areas of skin may avert the need for extensive neurologic tests.

Fig 23.5  Miliaria crystallina. (a) Small, clear vesicles on the skin of a dermatologic colleague after a period of intensive sporting activity. (b) Larger lesions: the central umbilication represents the tethering effect of the sweat follicle.

Fig 23.6  Miliaria rubra on the face of a neonate. This is a common problem, due to keeping babies too well wrapped up in layers of clothing and blankets. Neonatal toxic erythema may occasionally need to be excluded (see Ch.19).

Fig 23.7  Miliaria pustulosa in an area of hot, red skin overlying a septic arthritis. The pustules were, however, sterile on culture, and due to locally increased temperature.

Fig 23.8  Fox – Fordyce disease. Yellowish papules in the axilla, which may be tightly grouped as a confluent area of involvement.

Anhidrosis related to systemic disorders

Anhidrosis or hypohidrosis occurs in hypothyroidism, Fabry disease, and Sjögren syndrome, on the legs in Guillain–Barré syndrome, and locally in lesional skin in scleroderma, granulomatous disorders, vasculitides, and other scars. A variety of drugs may affect eccrine glands, either as part of their pharmacologic action (anticholinergics and tricyclics) or as a side effect, especially cytotoxic agents, which may produce neutrophilic eccrine hidradenitis or eccrine squamous syringometaplasia (Ch. 18).

Other disorders of the eccrine or apocrine sweat apparatus

Hidradenitis suppurativa is discussed in Chapter 10, as it may coexist with acne, and the treatments are similar.

Miliaria

Miliaria occur during periods of rapid sweating related to exertion or high-temperature surroundings (Figs 23.5 – 23.7). They may present as tiny, clear intraepidermal vesicles (miliaria crystallina); small, red papules (miliaria rubra, ‘prickly heat'); or pustules. Prickly heat is common in travelers from temperate climates to hotter and more humid countries, and is best avoided by cool bathing and avoidance of excessive temperatures for prolonged periods.

    Prickly heat is often confused with polymorphic light eruption (PLE) in holidaymakers who develop rash shortly after arriving in a sunny area (non-dermatologic medical practitioners often make the same errors, overdiagnosing prickly heat when the problem was actually PLE). Especially in young women, PLE is probably the commoner problem. As sunlight avoidance often parallels avoidance of high temperature, distinction may be difficult, especially in retrospect.

    Miliaria are often seen in neonates due to excessive amounts of warm bedding, especially in the context of febrile illness. In very young babies, miliaria need to be distinguished from erythema toxicum, in which the small pustules contain numerous eosinophils.

Fox–Fordyce disease

This is a variably itchy eruption in the apocrine skin areas, especially the axilla, which mainly affects young women (Figs 23.8 – 23.10). It is due to apocrine sweat retention with plugging of the follicles by detached apoeccrine secretory cells, leading to epidermal spongiosis and deeper inflammation. The lesions are discrete yellowish-colored papules, with absence of or sparse hair growth in the affected region. It often requires no treatment, but may respond to topical tretinoin or improve if the patient takes an oral contraceptive.

Fig 23.9  Fox–Fordyce disease. Here the yellowish papules in the axilla are more scattered.

Fig 23.11  Chromhidrosis, colored sweating, is usually apparent as staining of clothes, seen best in the cotton fibers along seams. Colors include yellow, brown, red, green (a), and blue-black (b). UV microscopy of garment fibers (c) belonging to the patient whose clothes are shown in (a) demonstrated yellow fluorescence (most clothing fibers fluoresce blue due to optical brighteners in washing detergents); axillary skin biopsy demonstrated that her apocrine sweat glands also autofluoresced with a yellow color.

Chromhidrosis and bromhidrosis

Chromhidrosis is the production of colored apocrine sweat, due to lipofuscins in the sweat (Fig.23.11). It is common to a mild extent as a yellowish brown color, but on occasions may be green, red, or black, due to different oxidation states of the lipofuscins. Occasionally, the problem may actually be chromogenic bacteria or fungi, which should be excluded by microbiologic cultures. The usual sites are the forehead, the cheeks, or the axillae, where patients may complain of stained clothing. The lipofuscins can be identified by their ability to autofluoresce under UV light, either on clothing or in the sweat glands of biopsy material from the affected site.

    Bromhidrosis is production of smelly sweat. This is usually apocrine in origin due to bacterial action on apocrine sweat, but some odors relate to eccrine sweat (such as the smells of various aminoacidurias).

Neutrophilic eccrine hidradenitis

This disorder occurs in two main settings. As noted earlier, it may occur as a drug eruption, most commonly in patients having chemotherapy for hematologic malignancy, in which case it generally affects the hands; it also occurs as painful nodules on the sole of the foot in children. In this situation, hyperhidrosis, friction, and getting cold wet feet have all been proposed as the cause. It is usually self-resolving over a few weeks in this pattern.

PRACTICE POINTS

Sebaceous glands

Acne is discussed in Chapter 10.

Seborrhea and normal sebaceous variants

Excessive greasiness of the skin is a somewhat subjective symptom (Fig.23.12), which can be quantified if necessary using commercially available tape strips. It is a common feature of teenage skin due to hormonal stimulation of sebaceous glands, and therefore often accompanies acne; in such patients, it is improved considerably by systemic isotretinoin, but usually recurs shortly after a treatment course has been completed.

    Seborrhea is also a feature of several other disorders, including nevoid basal cell carcinoma (Gorlin) syndrome (Ch.32), Parkinson disease, epilepsy, acromegaly, and some virilizing disorders in women. However, seborrheic dermatitis does not correlate with high sebum excretion.

    Several minor and relatively common conditions affect sebaceous glands, which may be best viewed as normal variants, including Fordyce spots (later), sebaceous hyperplasia (later), juxtaclavicular beaded lines (Fig. 23.13), and hamartoma moniliformis (Fig. 23.14).

Fig 23.12  A degree of greasiness of the nose and forehead is normal, but some patients find this hard to accept. Sebum can often be squeezed out of the nasal sebaceous glands, forming ‘sebaceous worms', which may be viewed as abnormal by some individuals.

Fig 23.13  Juxtaclavicular beaded lines are a common normal variant, which histologically have prominent sebaceous glands. They look pale in white skin (a) but dark in skin of color (b). (From Lawrence CM, Cox NH . Physical Signs in Dermatology, 2nd edn. London : Mosby, 2002.)

Fig 23.14  Hamartoma moniliformis is not really a sebaceous gland abnormality but is a normal variant in which there is minor fibrosis around otherwise apparently normal follicular structures on the nose, temples, forehead, and neck.

Sebaceous hyperplasia

Sebaceous hyperplasia is a common disorder of facial skin, usually on the cheek or forehead (Fig.23.15). Lesions consist of a ring of yellowish papules with a small central pit; this represents the tethering effect of the central follicle around which the hyperplastic sebaceous glands are arranged. The lesions may be mistaken for basal cell carcinomas but are yellowish, always have a central pit even if minute in size, are usually multiple, and show limited growth in size.

    Sebaceous adenomas (see Fig.23.52) may be mistaken for sebaceous hyperplasia. These are a cutaneous marker of internal malignancy and may occur in patients with cutaneous sebaceous gland malignancies; they are discussed later (Muir–Torre syndrome).

Fig 23.15  Sebaceous hyperplasia is a common disorder, usually best seen on the forehead or cheeks. Lesions are usually multiple, always yellowish, and always have a doughnut-shaped arrangement of papules with a small central dimple where the sebaceous glands are tethered by the central follicle. They may be confused with basal cell carcinoma, but basal cell carcinomas of this small size are not usually umbilicated.

Fordyce spots

These are small, yellow papules that are ectopic sebaceous glands (Figs 23.16 and 23.17). They are found mainly in the mouth, especially on the lips, where they are a common normal variant. They also occur on the penis and vulva, and sometimes other sites such as the areolae. Their importance is purely that they may be confused with disorders such as candidiasis in the mouth, or warts on the penis.

Fig 23.16  Fordyce spots are ectopic sebaceous glands. They are usually best seen on the buccal mucosa just inside the lips (especially the lateral aspects of the upper lip) or inside the mouth.

Fig 23.17  Multiple sebaceous glands may also occur on the penis, vulva, and areola. Patients with multiple penile sebaceous glands are occasionally referred if the lesions are mistaken for warts.

Fig 23.18  (a,b) Cylindroma. These lesions often occur on the scalp or temple area, and may be multiple. They usually have a rather reddish brown color with prominent surface vessels, and the skin appears tightly stretched around them. (c) Cylindromas (visible on the scalp) and trichoepitheliomas (affecting the central face) may occur together as a familial disorder with dominant inheritance (Spiegler–Brooke syndrome). In such cases, both types of tumor are usually multiple. (Panels b and c courtesy of Michael O. Murphy, M.D.)

Fig 23.19  (a,b) Pilomatricomas most commonly occur in children, and are usually more easily palpated than seen. They are typically hard, smooth (but often rather knobbly), and tethered to the skin but mobile at the deeper aspect. (b) Some pilomatricomas are more inflammatory and superficial. This type sometimes extrudes calcified material through the skin as small, white spicules, which probably accounts for the inflammatory component.

Fig 23.20  Some pilomatricomas grow very large, usually at non-facial sites where the patient may ignore them for long periods; this patient presented because of the discharge of calcium through the eroded area.

Fig 23.21  Solitary trichoepithelioma on the cheek. Many skin appendage tumors occur in solitary (usually sporadic) and multiple (often inherited) forms.

Fig 23.22  Multiple trichoepitheliomas. The central face, chin, and scalp margin are the most frequent sites for this disorder. In patients with a young age of onset, the lesions may resemble the angiofibromas of tuberous sclerosis (Ch 19).

Fig 23.23  Trichofolliculoma. These lesions may have clusters of small hairs protruding from their central pit, as shown here.

Fig 23.24  Dilated pore of Winer is probably not uncommon but may be small and trivial, such that it can be an incidental finding. A small pit on the forehead, ear, or cheek is typical.

PRACTICE POINTS

White/Cox: Diseases of the Skin, 2ed.(c) 2006, Elsevier Inc. All rights reserved.