Peter Noronha, MD

An 11-year-old boy with 4-month history of acnelike rash on his face and both upper arms. Rash is associated with redness and itching. Application of adapalene gel resulted in no change.

Patient has history of chronic otitis media. He is otherwise healthy.

Erythema and follicular papules noted in maxillary and preauricular areas bilaterally. Erythema and hyperkeratotic follicular papules noted on both upper arms. Both external ears and pinnae are erythematous.

No evidence of alopecia, eyebrow thinning, follicular atrophy, or scarring.



 Keratosis pilaris is a benign keratinization disorder characterized by keratinous plugs in follicular orifices. Its prevalence has been reported to be as high as 44%.

 The rash has 2 patterns of presentation:

• Lesions begin in childhood (before age 2 years), affect the face and arms, peak in early adolescence, and resolve in later years.
 • Lesions begin in adolescence, affect the lateral aspects of the arms and legs, and spontaneously involute in adulthood (mid-20s).

Keratosis pilaris rubra-as seen in this patient-is characterized by follicular papules on the face and cheeks, prominent erythema, and hyperkeratotic papules on the upper arms. The thighs and buttocks may also be affected. This variant is also called keratosis pilaris rubra faceii and is thought to be underrecognized.

The cause remains unknown. An autosomal dominant mode of inheritance with variable penetrance has been reported.

 Other modes of inheritance have been postulated.

Keratosis pilaris has been associated with atopy,

 It may be associated with Cushing disease, hypothyroidism, vitamin A intoxication, vitamin C deficiency, monilethrix, Hodgkin disease, monosomy 18p, and cardio-facio-cutaneous syndrome.

Histopathological examination reveals a nonspecific pattern of distended follicular orifices with keratin plugs and mild inflammatory changes in the dermis.

CLINICAL FEATURES AND DIFFERENTIATION FROM VARIANTS

Keratosis pilaris manifests as tiny, keratotic, follicular papules with variable erythema.

 The rash appears like “nutmeg grater” skin or chicken flesh and feels rough. It may be pruritic. The lesions have a predilection for the lateral aspects of the upper arms (92% of patients), thighs (59%), and buttocks (30%); they develop less frequently on the cheeks.

There are several recognized variants of keratosis pilaris; the features of some of these overlap to a degree. The variants whose features are most similar to those of keratosis pilaris rubra are:

Erythromelanosis follicularis faciei et colli

. This rash develops in the second decade of life, most commonly in males, and is characterized by symmetrical follicular papules with perifollicular erythema on the cheeks, forehead, and neck.

 It can be differentiated from keratosis pilaris rubra by the presence of hyperpigmentation, lack of involvement of the torso, and late onset of presentation.

 The most prominent features of this rash are follicular atrophy and scarring. There are 3 types:

 (also called keratosis pilaris atrophicans faciei) initially affects the lateral third of the eyebrows and later progresses to the cheeks and forehead. It is mostly associated with keratosis pilaris of the arms and legs.

 is characterized by follicular plugs and pitlike depressions up to 1.5 mm in diameter, predominantly on the cheeks. These pits coalesce, resulting in a “worm-eaten” or “honeycombed” appearance.

Keratosis follicularis spinulosa decalvans

 begins in infancy and is characterized by follicular spines on hair bearing areas, especially the scalp, eyebrows, and eyelashes. It results in scarring alopecia of the affected areas in puberty.

The differential diagnosis of keratosis pilaris includes atopic dermatitis, acne, rosacea, and pityriasis rubra pilaris. Clues to the diagnosis of keratosis pilaris rubra in the patient described include the chronic persistent course, the pattern of follicular papules and perifollicular erythema, and the resistance to treatment. The involvement of the arms and other parts of the body in addition to the face confirms the diagnosis of keratosis pilaris rubra.

Keratolytic agents such as salicylic acid preparation, topical retinoids, and tazarotene have been used with some success in patients with keratosis pilaris rubra.

 Topical preparations may aggravate the erythema, thus patients should be informed of this adverse effect.

 In other variants of keratosis pilaris, the response to topical therapy is variable and often unsuccessful.

 Other reported treatments include potassium titanyl phosphate laser therapy, topical corticosteroid therapy, pulsed dye laser therapy, and oral vitamin A.

Salicylic acid 6% ointment was prescribed for this patient. At follow-up a few months later, the erythema had decreased somewhat, but the hyperkeratotic papules remained unchanged.

 Mevorah B, Marazzi A, Frenk E. The prevalence of accentuated palmoplantar markings and keratosis pilaris in atopic dermatitis, autosomal dominant ichthyosis vulgaris and control dermatological patients. 

 Rogers M. Keratosis pilaris and other inflammatory follicular keratotic syndromes. In: Wolff K, Goldsmith LA, Katz SI, et al, eds. 

Fitzpatrick's Dermatology in General Medicine

. 7th ed. New York: McGraw-Hill; 2008:749-753.


 Marqueling AL, Gilliam AE, Prendiville J, et al. Keratosis pilaris rubra: a common but underrecognized condition. 

 Callaway SR, Lesher JL Jr. Keratosis pilaris atrophicans: case series and review. 

 Yosipovitch G, Mevorah B, Mashiach J, et al. High body mass index, dry scaly leg skin and atopic conditions are highly associated with keratosis pilaris. 

 Leung AKC, Kao CP. What's your diagnosis? Keratosis pilaris. 

 Judge MR, McLean WH, Munro CS. Disorders of keratinization. In: Burns DA, Breathnach SM, Cox NH, Griffiths CE, eds. 

. 7th ed. Oxford, England: Blackwell Publishing; 2004:34.60-34.62.


Articles

Itchy, Acne-Like Rash on a Boy’s Face and Upper Arms

 This thumb anomaly in a 16-month-old boy was noted within the first month of life. The mother heard an occasional popping sound when trying to straighten the thumb. The infant also had subcoronal hypospadias. He was otherwise healthy.

 is a stenosing tenosynovitis of the flexor pollicis longus tendon with flexion deformity of the interphalangeal joint. The common presentation is a fixed flexion deformity of the thumb on one hand or bilaterally. Trigger thumb is rarely seen in infants, although it accounts for 85% of all cases of trigger digits in childhood.



 The differential diagnosis includes congenital clasped thumb (thumb is held tightly beneath the flexed fingers) and congenital absence of the extensor pollicis longus (limp thumb). Trigger thumb may also be part of a syndrome, such as trisomy 13 syndrome.



 It remains unclear whether this is a congenital condition. In most cases, a specific cause is not determined, although there is evidence for a genetic predisposition. A family history of trigger finger may be obtained in some cases. An autosomal dominant pattern of inheritance has been suggested.

 Trauma is an unlikely cause.

 The presence of 2 or more congenital conditions, such as in this patient, may point toward a genetic syndrome. However, a literature search revealed no significant correlation between trigger thumb and hypospadias. These 2 conditions were thought to be isolated anomalies; no genetic workup was done.

 Infants with trigger thumb can be observed or treated conservatively with daily home stretching exercises. Often the digit can be straightened with passive stretching or splinting or both. However, in some cases the deformity may be rigid. One study showed that in the first 4 years of life, spontaneous resolution occurred in more than 60% of patients; in those who did not have resolution, more than 80% had some improvement in flexibility.

 Surgical correction may be considered for a trigger thumb that persists after this time.

Case and image courtesy of Peter Noronha, MD, and Imteyaz Khan, MD of the University of Illinois at Chicago.


1. Moon WN, Suh SW, Kim IC. Trigger digits in children. 

. 2001;26:11-12.
2. Cardon LJ, Ezaki M, Carter PR. Trigger finger in children. 

. 1999;24:1156-1161.
3. Ogino T. Trigger thumb in children: current recommendations for treatment. 

. 2008;33:982-984.
4. Baek GH, Kim JH, Chung MS, et al. The natural history of pediatric trigger thumb. 

This thumb anomaly in a 16-month-old boy was noted within the first month of life. The mother heard an occasional popping sound when trying to straighten the thumb. The infant also had subcoronal hypospadias. He was otherwise healthy.

What Is This Thumb Anomaly?

Seventeen-month-old Hispanic boy with 7-month history of a swelling on his back. Lesion first looked like a small "scar," then gradually grew over next few months. Lesion appeared to blister, with subsequent discharge of clear fluid. No symptoms other than intermittent pruritus at lesion site. Patient not taking any medications.

Child born prematurely at 32 weeks' gestation with uncomplicated postnatal course. Several months before lesion appeared, another had been present on his cheek. Earlier lesion was excised: diagnosis was pilomatrixoma.

Healthy-appearing child with normal growth and development. Small healed scar noted on the left cheek (site of pilomatrixoma).

The lesion on the back is a solitary tan-colored smooth-surfaced nodule of about 0.75 x 1.0 cm (

). No surrounding erythema or dyspigmentation.

Stroking of lesion with tongue blade causes wheal , followed by localized intense erythema (5 x 5 cm) (

) and discomfort. No flushing on cheeks or elsewhere.

Darier sign (named after the French dermatologist who first described the phenomenon) describes the formation of a wheal or blister on stroking of a lesion. In its classic manifestation, gentle rubbing or stroking of a lesion is followed by local itching and erythema and wheal formation within 2 to 5 minutes. This process may persist from 30 minutes to several hours.

 The sign may be demonstrable on clinically normal skin in patients who have the more generalized form of mastocytosis. Some patients may also have systemic flushing and generalized pruritus.

A positive Darier sign establishes the diagnosis of mastocytosis. Stem cell factor (produced by keratinocytes) stimulates the proliferation of mast cells, which leads to release of both histamine and heparin. This factor also increases the production of melanin by melanocytes, which leads to eventual hyperpigmentation.

The differential diagnosis of mastocytosis includes recurrent bullous impetigo, nevi, juvenile xanthogranuloma, and urticaria pigmentosa. Histopathological examination of the lesion site reveals monomorphic cuboid mast cells that infiltrate the upper dermis.

There are various presentations of cutaneous mastocytosis. The patient in this case has a 

, which presents at birth or in early infancy and may occur in any area. Initially, it may appear as an evanescent wheal or blister. With time, an infiltrated tan, pink, or yellow, orange-peel macule, plaque, or nodule develops at the site of the wheal or blister. Hyperpigmentation surrounding the lesion may develop and become prominent. Rarely, systemic signs of histamine release occur at this time, and multiple lesions may develop.

In a study of 55 patients with cutaneous mastocytosis, the most common presentation was involvement of trunk and extremities.

 Thirteen patients had a history of bullae; Darier sign was present in 34 of the 38 patients who were tested. Itching was the most common complaint, triggered by hot weather or hot baths.

Mastocytomas tend to regress spontaneously.

 Avoidance of triggers-such as rubbing, trauma, heat, ingestion of alcohol or radiocontrast media, and physical exertion-is the main therapy. If the lesion is in an area of friction or is frequently symptomatic, topical corticosteroids can be applied to decrease the histamine reaction and pruritus. Surgical excision of solitary lesions is a possibility if the patient is symptomatic.

 Surjushe A, Jindal S, Gote P, Saple DG. Darier's sign. 

 Valent P, Sperr WR, Schwartz LB, Horny HP. Diagnosis and classification of mast cell proliferative disorders: delineation from immunologic    diseases and non-mast cell hematopoietic neoplasms. 

 Valent P, Horny HP, Escribano L, et al. Diagnostic criteria and classification of mastocytosis: a consensus proposal. 

 Akoglu G, Erkin G, Cakir B, et al. Cutaneous mastocytosis: demographic aspects and clinical features of 55 patients. 

 Horny HP, Sotlar K, Valent P. Mastocytosis: state of the art. 

Author | Peter Noronha, MD

Articles

Itchy, Acne-Like Rash on a Boy’s Face and Upper Arms

What Is This Thumb Anomaly?

Solitary Nodule With a Positive Darier Sign