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OTHER CONDITIONS THAT ARE COMMON IN DARKER-SKINNED PATIENTS

Leukoedema

Etiology and pathogenesis

Leukoedema is a common, benign condition of the oral mucosa of black adults. Archard & Stanley (1973) concluded from a histologic analysis that the clinical changes are a result of a retained layer of parakeratotic cells. The condition is not premalignant.

Clinical

Clinical examination of the oral mucosa affected by leukoedema shows it to have a white-gray, edematous surface, which has been described as ‘filmy opalescence’ (Fig.21.31). The buccal mucosa is involved primarily, especially the middle and posterior portion, but the lingual mucosa may also be involved. This change may cover the greater part of the mucosa, or may occur in large, ill-defined patches. In well-formed lesions, impressions of the teeth are prominently seen along the occlusal line (bite line). The surface is soft, but scraping does not remove the changes. The condition is asymptomatic, except in the rare patient who complains of the involved mucosa being caught during mastication. Similar changes have been reported on the mucosa of the lip, uvula, tongue, and vagina.

Differential diagnosis

The main differentials are oral lichen planus, white sponge nevus, and candidiasis.

Treatment

No treatment is necessary, although cessation of smoking and improvement of oral hygiene may be recommended if appropriate.

PRACTICE POINTS

Pseudofolliculitis barbae

Etiology and pathogenesis

Pseudofolliculitis barbae (PFB) is a common condition of the beard area in any patients with curly hair who try for a close shave. It is particularly common in darker-skinned men of African-Caribbean ancestry. The underlying process is tissue damage and foreign body response to the patient’s own hair that has curved back into the skin. Dark- or pale-skinned women who shave in the axillary or pubic region may be similarly affected.

Clinical

Clinical examination shows multiple, symmetric inflammatory papules, many with a short whisker penetrating their base (Fig.21.32a). These papules are always found in close proximity (e.g. 1-3 mm) to a whisker. The submandibular area and neck are common locations. For unknown reasons, the mustache area tends to be spared. Pustules and occasionally abscesses are seen but, as noted earlier, any infection is a secondary event. Papules readily bleed with shaving. Postinflammatory hyperpigmentation and even keloid formation can develop. In longstanding disease, the whiskers can create grooves in the skin (Fig. 21.32b). The whisker then lies below the surface of the skin in the groove and is hard to cut by the usual shaving techniques. Sometimes a superficial, crisscross pattern can result. When these grooves have formed, the condition becomes very difficult to treat.

Differential diagnosis

The main differential is true (usually bacterial) folliculitis. Occasionally, patients with this condition are erroneously referred as having ‘resistant acne’.

Treatment

Growing a beard is curative. If patient’s work and his social and personal situations allow, immediate cessation of shaving is recommended. Over the following month, the patient should release any trapped hairs every few days (see technique described later). Even if the patient is unable to release all the hairs, the natural growth of the whisker will eventually create enough tension in the coil that it will pop out on its own. The doctor should always ask about the work situation and specifically ask if the patient needs a letter addressed to his employer excusing the patient from shaving. Of note, cessation of shaving may be employed for 3-4 weeks prior to any of the following procedures to release all hairs and reduce inflammation.
    If a close shave is necessary, several approaches may be tried. First, the patient may do well using a depilatory. Those with barium sulfide or with calcium thioglycolate should be tried, to be used every 2-4 days. Various razors are available and marketed for PFB. The foil guard razor has been studied and found beneficial. It contains a single, stainless steel blade that is buffered from the patient’s skin by a serrated foil guard. Alternatively, an adjustable razor may be used, with the patient selecting the very lowest settings to avoid a close shave. Twin blades should not be used, as they may lift the whisker, cut it, and allow it to retract below the surface. This can lead to intrafollicular penetration. When any razor blade is used, the patient must:

    Putting the free hand in one’s pocket is helpful. Finally, preshave measures to soften the whiskers are important. A shaving cream should be applied and allowed to sit for 2-5min before shaving. Some recommend a second application. This long presoak softens the whiskers, making one pass of the razor more effective.

   There is a tendency for some patients to shave infrequently. The danger here is that the whisker may have time enough to form an arc and circle back into the skin. Thus shaving is recommended at least every 3 days. Alternatively, the use of an electric shaver may be an improvement over a blade for many. The three-headed rotary electric razor can produce good results. It is important to use the electric razor in a circular motion, with a ‘gentle hand’. If the patient has a significant beard, the clipper portion of the shaver should be used first to remove the bulk of the whiskers.
   Electric clippers are advocated by a variety of authors as an ideal approach to therapy. Shaving may be done daily, leaving about a 1-mm stubble, which in the dark-skinned patient is usually less noticeable than in the pale-skinned patient.
   Trapped hairs are a constant source of irritation and are less accessible to any shaving technique. Thus hair-releasing procedures as outlined
here should be performed in the first month of growing a beard or in conjunction with the use of chemical depilatories, razors, electric shavers, or clippers. The typical approach is to instruct the patient to use a toothpick and a magnifying mirror to gently extract the hairs. No plucking please.
   Inflammation in PFB is not caused primarily by infection, but may be aggravated by it. Thus topical clindamycin or erythromycin once or twice daily may be tried when inflammation is significant.
   Finally, treatment with long-pulsed Nd:YAG laser, diode, or other long-pulsed infrared lasers can ablate the hair and dramatically reduce or even clear PFB, although multiple treatments are usually necessary.

Hair disorders

Tinea capitis due to Trichophyton tonsurans is much commoner in urban-living African-Caribbean patients than it is in other groups in the UK.
   There are also disorders that are more commonly seen due to cultural habits, for example pomade acne (see Acne in the darker-skinned patient, Ch.10), hot comb alopecia, and traction alopecia due to hair braiding.

Punctate keratosis of palmar creases

The black patient may develop small hyperkeratotic plugs or, if they are removed, shallow pits in the large creases of the palms and fingers (Fig.21.33). The soles may also be involved. Manual labor and atopy have been reported as associations, but these remain to be confirmed. Both sporadic and familial cases occur. No treatment is needed or known to be effective.

Infundibulofolliculitis of Hitch and Lund

Innumerable tiny follicular papules are seen, most commonly in the darker-skinned patient. This condition is considered by some to be a variant of follicular eczema (Fig.21.34 and see Fig. 6.3). The lesions may be darkly pigmented in colored skin.
   Juxtaclavicular beaded lines appear similar.

Ainhum

Etiology and pathogenesis

Ainhum is a benign but disfiguring autoamputation of the fifth toe. It primarily affects East African men who walk barefoot. The term ainhum is derived from the word in the East African language of Nagos meaning ‘to saw’. Chronic rotational stresses and trauma from walking barefoot are of central importance. Common to most patients is a history of shoelessness for some years before onset of the disease, usually since childhood.

Clinical

Initially, a sulcus appears at the plantar junction of the fifth toe with the sole. It usually starts medially, coinciding with the plantar-digital fold, but it can occasionally occur beyond it. Then the groove spreads around the toe until it forms a complete circle (Fig. 21.35). Over time, the groove deepens until it ulcerates. Sterile bone resorption then begins. The bone becomes spongy, and the soft tissue converts to an avascular fibrous cord. Ultimately, the toe may hang from the foot by a thin band of soft tissue. Spontaneous amputation can then occur. Both fifth toes are affected in the majority of patients, but unilateral involvement is also common, and occasionally the fourth toe may be affected.

Differential diagnosis

Pseudoainhum or circumferential constriction of a digit (finger or toe) may occur in a variety of disorders, including many of the keratodermas, leprosy, erythropoietic protoporphyria, Olmsted syndrome, porokeratosis of Mibelli, and from strangulation by a hair or string.

Treatment

Trauma should be avoided, and the wearing of shoes or sandals is important. Amputation for a dangling digit may be necessary, although allowing autoamputation to occur is not unreasonable in such cases. Excision of the groove, followed by surgical Z plasty, may be performed for all grade I lesions and early grade II lesions. Any bacterial or fungal infection of the sulcus should be treated.

Keloid scars

Keloids are more common in darker than in white skin and are difficult to treat. Therapy is discussed in Chapter 22. However, they deserve brief mention here, as it is important to be aware that some options, such as cryotherapy or radiotherapy, may cause depigmentation and are therefore of limited benefit in darker skin.

Other dermatoses in darker-skinned patients

Certain inflammatory dermatoses have racial predilection for frequency or severity in darker-skinned patients. Sarcoidosis (Ch.11) is much commoner in black Africans, and its patterns vary compared with white people; erythema nodosum and lupus pernio are less common, but nodular and ulcerative forms, papular facial lesions, and chronic arthritis are all more common. Systemic lupus erythematosus (Ch.13) has increased severity in West Indians and in African Americans. In some people of color resident in developed countries, atopic dermatitis seems to have an increased incidence in black or Asian children; lichenification is also often prominent in darker skin. The clinical appearance of many dermatoses may be altered by skin color, masking of erythema making diagnosis more difficult.
   Facial African-Caribbean childhood eruption (FACE) is a papular mid-facial granulomatous disorder of black children that enters the differential diagnosis of acne.
   Keloid scars generally (Ch. 22) and nuchal acne keloid (acne keloidalis nuchae, Ch. 10) are more common in black skin.

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