Isotretinoin therapy is associated with early skeletal radiographic changes

Therapeutic Options for the Treatment of Darier's Disease: A Comprehensive Review of the Literature

Darier's disease (also known as keratosis follicularis or dyskeratosis follicularis) is an autosomal dominant inherited disorder which manifests as hyperkeratotic greasy papules in the first or second decade of life. Aside from symptom management and behavioral modifications to avoid triggers, there are currently no validated treatments for Darier's disease (DD). However, a variety of treatments have been proposed in the literature including retinoids, steroids, vitamin D analogs, photodynamic therapy, and surgical excision. The purpose of this review article is to identify therapeutic options for treating DD and to outline the evidence underlying these interventions. A search was conducted in Medline for English language articles from inception to July 4, 2020. Our search identified a total of 474 nonduplicate studies, which were screened by title and abstract. Of these, 155 full text articles were screened against inclusion/exclusion criteria, and 113 studies were included in our review. We identified Grade B evidence for the following treatments of DD: oral acitretin, oral isotretinoin, systemic Vitamin A, topical tretinoin, topical isotretinoin, topical adapalene gel, topical 5-flououracil, topical calciptriol and tacalcitol (with sunscreen), grenz ray radiation, and x-ray radiation. All other evidence for treatments of DD consisted of case reports or case series, which is considered grade C evidence. Considering the quality and quantity of evidence, clinicians may consider initiating a trial of select topical or oral retinoids first in patients with localized or generalized DD, respectively.

Isotretinoin for acne vulgaris - an update on adverse effects and laboratory monitoring

A significant barrier to the usage of isotretinoin has been concerns regarding its adverse effect profile. The dose-dependent mucocutaneous side effects of isotretinoin are well recognised and easily managed, particularly if a lower dose is used. A possible association with depression has gained widespread media attention and is a source of concern for many patients and their carers, but data from prospective studies and recent meta-analyses has been reassuring. Furthermore, there has been much confusion amongst both patients and physicians regarding a possible association with inflammatory bowel disease, as well the ocular and rheumatological adverse effects of isotretinoin. We provide an update on the evidence surrounding the adverse effects of isotretinoin, and discuss practical strategies to prevent and manage these adverse effects. We also discuss appropriate laboratory monitoring for patients taking isotretinoin.

Isotretinoin updates

Acne vulgaris is a chronic inflammatory disease of pilosebaceous follicles commonly affecting adolescents and young adults. This disease has a profound psychological impact on affected individuals and treatment has been shown to significantly improve both self-esteem and quality of life. Isotretinoin is an effective medication used primarily in severe cystic acne patients. Over the past 30 years, this medication has revolutionized the treatment of acne. However, despite its popularity there are numerous side effects associated with its use. Most of its side effects are predictable and dose dependent, which has led to the development of variable dose regimens. Unfortunately, rare but significant side effects (e.g., depression, inflammatory bowel disease) do occur and necessitate careful monitoring to improve clinical outcomes and minimize potential adverse events.

Retinoid toxicity

The long-term effects of N-ethylretinamide (NER) on the haematology of the rat, and the dose-related effects of retinoids on lymphoid organs of the mouse and rat were investigated. Retinoid-induced long-bone changes were used to develop a method for quantifying skeletal effects. This technique was used to investigate the activity of five retinamides in inducing long-bone changes in the rat. The ability of non-steroidal anti-inflammatory compounds (NSAICs) to prevent retinoid-induced skeletal effects was examined, and preliminary investigations made into the mechanisms of retinoid-induced long-bone remodelling. NER-fed rats had reduced red blood cell counts and fibrinogen values. Retinoids caused dose-related proliferation of the spleen and lymph nodes in the mouse and to a lesser extent in the rat. They induced dose-related reductions in femoral diaphysis and medullary cavity diameters in both rats and mice. Aspirin prevented NER-induced changes of rat long bones, but subsequent studies indicated this effect may be closely dependent on the dose level of both the retinoid and NSAIC administered. Retinoids induce rapid long-bone remodelling in the rat which tends to revert on feeding a control diet, but remodelling processes are different in the young growing rat and the mature animal.

Vitamin A: is it a risk factor for osteoporosis and bone fracture?

Results from observational studies of the association between vitamin A intake or serum concentration and bone mineral density or fracture are mixed. The inconsistencies may be due, in part, to difficulties in obtaining an accurate assessment of vitamin A intake or status. Serum retinol is a poor measure of vitamin A status because it is subject to homeostatic control. Stable-isotope-dilution methodology gives a validated assessment of the total-body and liver vitamin A stores and is recommended in future studies on vitamin A status and osteoporosis. The potential for exacerbating an already serious public health problem with intakes of vitamin A currently considered safe indicates further research into this matter is warranted.

Lack of significant skeletal changes after long-term, low-dose retinoid therapy: case report and review of the literature

BACKGROUND

Long-term systemic retinoid therapy has been associated with skeletal side effects. There have been reports of diffuse idiopathic skeletal hyperostosis (DISH) syndrome, calcification of ligaments, and osteoporosis, as well as premature fusion of epiphyses and modeling abnormalities of long bones, occurring in patients on chronic high-dose isotretinoin, etretinate, and acitretin therapy. Low-dose acitretin has been used for many years as monotherapy or in combination with other systemic therapies for psoriasis. Evidence to date suggests that the frequency of symptomatic bony effects is quite low in these patients.

OBJECTIVE

To present the radiologic findings of a patient on long-term, low-dose acitretin and etretinate and to review the literature on the radiologic evidence of skeletal side effects during retinoid therapy.

METHODS

Case report and literature search.

RESULTS

A patient on low-dose acitretin had no significant radiologic abnormalities associated with retinoid use after 9 years of treatment. A review of the literature revealed conflicting reports on the incidence of radiologic abnormalities in patients on retinoid treatment.

CONCLUSION

The evidence to date does not substantiate a clear link between radiologic skeletal abnormalities and long-term, low-dose acitretin or etretinate therapy.

Effect of a single course of isotretinoin therapy on bone mineral density in adolescent patients with severe, recalcitrant, nodular acne

BACKGROUND

Adverse changes in bone have been reported for patients undergoing high-dose, long-term (several years) isotretinoin therapy for disorders of cornification. The effect of short-term (4-5 months) therapy at the lower dose recommended for acne on bone development in younger, growing adolescent (12-17 years) patients has not been well studied.

OBJECTIVE

The purpose of the study was to evaluate the effect of a standard, single course of isotretinoin (Accutane) therapy on bone mineral density (BMD) of the lumbar spine and hip in adolescents ages 12 to 17 years with severe, recalcitrant, nodular acne.

METHODS

In this open-label, multicenter study, 217 adolescents (81 girls) with severe, recalcitrant, nodular acne were enrolled and treated with isotretinoin twice daily with food at the recommended total dose of approximately 1 mg/kg for 16 to 20 weeks. BMD in the lumbar spine and hip was measured at baseline and at the end of therapy by dual energy radiograph absorptiometry.

RESULTS

There was no clinically significant mean change in BMD measured at the lumbar spine (+1.4%, range: -4.9% to +12.3%) or total hip (-0.26%, range: -11.3% to +15.0%). Hyperostosis was not observed in any patient. Typical efficacy expected in the treatment of acne was observed.

CONCLUSIONS

A 16- to 20-week course of isotretinoin treatment at the recommended dose for severe acne has no clinically significant effect on lumbar spine and total hip BMD in the adolescent (12-17 years) population.

Safety issues in isotretinoin therapy

Isotretinoin (Accutane, Roche Laboratories Inc, Nutley, NJ) is an important drug, not only for the treatment of severe acne, but also for other diagnoses and in chemoprevention settings. Because the use of isotretinoin is increasing, it is important for physicians to be aware of the adverse events, toxicities, and management issues related to its use. The most important issue is that of congenital defects, which has resulted in new pregnancy prevention policies and programs implemented by the manufacturer. A relatively new concern is that of depression associated with isotretinoin use, also resulting in new policies placed by the manufacturer and the FDA. The most common adverse effects observed during treatment are mucocutaneous and ocular in nature, but laboratory abnormalities and effects in the nervous, musculoskeletal, gastrointestinal, pulmonary, hematologic, and other systems are also described. Additionally, potential drug interactions, follow-up, and toxicity prevention measures are discussed.

Posttransplantation skin cancer: scope of the problem, management, and role for systemic retinoid chemoprevention

Long-term immunosuppression necessary for transplantation places susceptible individuals with chronic actinic damage at increased risk for the development of aggressive skin cancers. Candidates for transplantation should be evaluated for the risk factors associated with skin cancer. Those who are at risk should be educated in the measures for and the importance of diligent UVR protection, frequent self-examination of the skin, and regular dermatologic evaluation to minimize the morbidity and morality from NMSC. Identified skin cancers (especially SCC) should be treated aggressively. Individuals who are actively developing many cancers may be candidates for retinoid chemoprevention.

Retinoic acid responsiveness of cells and tissues in developing fetal limbs evaluated in a RAREhsplacZ transgenic mouse model

Limb morphogenesis is a complex phenomenon in which retinoids play an important role. Abnormal maternal retinoid levels from high oral doses cause fetal malformations, including abnormalities of the musculoskeletal system. Our purpose was to identify the retinoid-responsive cells in bone and cartilage during limb development by using a transgenic line of mice containing a reporter gene insert consisting of a retinoic acid response element linked to an Escherichia coli beta-galactosidase gene. Transgenic fetuses from day 11.5 after conception to birth (day 20) were analyzed histologically. Retinoid-responsive cells and tissues were first seen in the limb bud at 12.5 days in the webs between the forming digits. The webs stained maximally at 14.5 days, after which staining intensity subsided. Staining in the muscles was detectable at 13.5 days, at a stage coinciding with myoblast fusion. Specific regions of perichondrium and periosteum also stained at this stage. Occasional staining was observed in individual chondroblasts in all chondrogenic regions, including hypertrophic chondroblasts and certain articular surfaces of developing joints. Staining of these tissues decreased in intensity in subsequent stages. Osteoclasts started to express beta-galactosidase at 15.5 days and continued to stain into maturity. Our results indicate that specific subsets of cells respond to retinoids at specific stages in the course of normal limb development. In hypertrophic chondrocytes and cells in the webs and joints that display such a response, retinoid-induced effects may be linked to cell death that occurs in these regions. Staining in muscle, perichondrium, and periosteum may reflect retinoid-induced effects associated with cell differentiation and growth. These results suggest that retinoids play a role in a variety of tissues, including bone and cartilage, at specific stages during morphogenesis.

Isotretinoin therapy in acne vulgaris: a 10-year retrospective study in Singapore

BACKGROUND

The use of isotretinoin, a first generation synthetic retinoid, in the treatment of patients with severe acne vulgaris was a major therapeutic advance in dermatology. This 10-year retrospective study reviews the effectiveness of isotretinoin in patients with acne vulgaris seen in a skin clinic in Singapore.

METHODS

The case records of 250 cases of severe inflammatory and nodulocystic acne treated with isotretinoin were analyzed with reference to the demographic data, response to isotretinoin, dosage and cost of isotretinoin used, adverse effects, clinical follow-up, and relapse.

RESULTS

Two hundred and fifty patients, 171 men (68.4%) and 79 women (31.6%), with different types and grades of acne vulgaris were studied. The dose of isotretinoin used ranged from 0.33 to 1.0 mg/kg/day (median 0.5 mg/kg/day) for a period ranging from 1 to 12 months (median 4 months). Response was excellent in 127 (50.8%) patients, good in 86 (34.4%), fair in 30 (12.0%) and poor in 7 (2.8%). Relapse occurred in 14 (5.6%) patients over a 6-month follow-up period. Adverse effects were noted in 140 (56.0%) patients and were mild in most cases. Eighteen (7.2%) patients had to discontinue the drug due to significant side effects.

CONCLUSION

This study confirms that isotretinoin is very effective for severe acne, and complete remission can be induced in more than 90% of cases even with lower dosage regimens. Significant clinical improvement can be achieved with the use of lower doses (mean 0.5 mg/kg/day) for an average of 4 months of treatment with lower risk of adverse effects.

Bone changes and their significance in children with ichthyosis on long-term etretinate therapy

Anxiety about the use of etretinate in children has been provoked by several reports describing skeletal abnormalities during long-term therapy. However, we have observed no evidence of skeletal toxicity in 42 children treated over an 11-year period. Radiological screening before and during treatment has failed to reveal abnormalities that would influence our decision to commence or to continue etretinate administration. We recommend that children who are to be treated with etretinate should have a baseline selective skeletal survey, with follow-up radiology restricted to those with pretreatment radiological abnormalities and those who develop musculo-skeletal symptoms. In addition we advise that dosage should not exceed 1 mg/kg/day. If these guidelines are followed, we believe that long-term therapy with etretinate can be given to children, with an acceptable margin of safety.

Rheumatological symptoms due to retinoids

Isotretinoin and etretinate are synthetic derivatives of vitamin A widely used in the treatment of dermatological diseases, mainly those affecting keratinization. They have numerous side-effects, among which the rheumatic symptoms are not the most common or the most severe. The main skeletal adverse reaction of retinoids is hyperostosis. It mainly occurs with protracted treatments and high dosages, and its incidence may exceed 80% after a few years of administration. Hyperostosis is axial, located in the cervical and thoracic spine, and may be responsible for limitation of movement; in the appendicular bone, enthesopathies occur at the foot, pelvis, hip, and less commonly the shoulder and elbow. They are usually mild and asymptomatic. The radiological appearance is very similar to diffuse idiopathic skeletal hyperostosis. Isotretinoin tends to be responsible for axial involvement, etretinate for peripheral locations. The other skeletal side-effects are uncommon and include periosteal proliferation, calcification of the interosseous membrane of the forearm and diffuse radiological bone hyperlucency. In children, premature epiphyseal closure is very rare. About 20% of patients complain of musculoskeletal pain and arthralgias. A few cases of true arthritis have been reported. Retinoids may be responsible for muscular damage and an abnormality of muscular tone resembling the stiff-man syndrome. Some cases of necrotizing vasculitis and three cases of Wegener's granulomatosis have been observed in patients treated with retinoids. Except for these latter arguable cases, rheumatoid syndromes due to retinoids are rather benign, and should not be an obstacle to the future development of their therapeutic utilization.

Musculoskeletal syndromes associated with acne

The acne conglobata (AC)-, acne fulminans (AF)-, and isotretinoin-associated musculoskeletal syndromes are three distinct clinical entities. The AC-associated musculoskeletal syndrome occurs primarily in black men over the age of 22, who develop sacroilitis with or without a peripheral arthropathy. In contrast, the AF-associated musculoskeletal syndrome is found almost exclusively in white male teenagers. Fever, weight loss, and arthralgias are prominent components of this syndrome. A unique feature of the AF-associated musculoskeletal syndrome is osteolytic lesions that occur most frequently in the clavicle, sternum, long bones, and ilium. The isotretinoin-associated musculoskeletal syndrome occurs with equal frequency in male and female acne patients. Mild, transient myalgias and arthralgias are very common and do not require discontinuation of isotretinoin therapy. Asymptomatic, small, hyperostotic lesions of the spine occur in approximately 10% of acne patients with the isotretinoin-associated musculoskeletal syndrome.

Isotretinoin-basal cell carcinoma prevention trial. Design, recruitment results, and baseline characteristics of the trial participants. The ISO-BCC Study Group

The Isotretinoin-Basal Cell Carcinoma Prevention Trial (ISO-BCC Study) is a double-masked, randomized, placebo controlled, multicenter clinical trial. It is the first intramural cancer chemoprevention trial sponsored by the Division of Cancer Prevention and Control of the National Cancer Institute. This trial was designed to evaluate the effectiveness of chronic administration of low dosage levels (10 mg) of a synthetic retinoid, isotretinoin, in reducing the incidence of basal cell carcinoma in a high-risk population and to determine the incidence and severity of side effects associated with this long-term treatment. Between 1984 and 1987, eight clinical centers enrolled 981 participants between the ages of 40 and 75, who had two or more biopsy proven basal cell carcinomas in the 5 years before trial entry. This article describes the trial design, recruitment results, and baseline characteristics of the participant population in the ISO-BCC Study.

Comparative assessment of the toxicology of vitamin A and retinoids in man

As the title implies, any assessment of the toxic effects of vitamin A derivatives must distinguish between vitamin A in the truest sense, i.e. retinol, and retinoic acid and its synthetic derivatives. Just as no single description is universally applicable to the mode of action of vitamin A derivatives, so too do their toxic effects defy generalization. The recommendation made in 1982 by IUPAC [Eur. J. Biochem., 129 (1989) 1] to designate all derivatives with the typical structure of the vitamin as being retinoids may be chemically logical and correct but, when it comes to describing the effects and side-effects of vitamin A derivatives, it leads to misunderstandings. Retinol, which is frequently used as synonym for vitamin A, can eliminate all symptoms of vitamin A deficiency if it is taken in sufficient quantity with the diet. The term retinol will therefore be used here as a synonym for vitamin A whereas retinoic acid and its derivatives--including the synthetic ones--will be referred to as retinoids because they do not cover the whole spectrum of effects exerted by retinol and because they also vary markedly in their side-effects. In contrast to the nomenclature proposed by IUPAC, this system provides a clear and logical distinction for describing biological processes. Other authors have favoured it in recent times [Chytil, F., J. Am. Acad. Dermatol., 15 (1986) 741; Olson, J.A., Semin. Oncol., x (3) (1983) 290; Olson, J.A., Am. J. Clin. Nutr., 45 (1987) 704; Zbinden, G., Acta Dermatovener., 74 (1975) 36]. By vitamin A, therefore, is meant all derivatives that can possibly originate from retinol in the organism. This also covers the small quantities of retinoic acid formed from retinol. On the other hand, by retinoids is meant the natural retinoic acid derivatives and their synthetic forms in their special modes of action. Since retinoic acid cannot be reduced to retinol in the organism, this nomenclature provides a clear demarcation within the biological system. Vitamin A is essential to the growth and development of higher life forms and functions in many different ways within the organism. Although vitamin A was one of the first vitamins to be described, even today there is still some uncertainty as to its mode of action, with the exception of that of retinal (vitamin A aldehyde) in vision.(ABSTRACT TRUNCATED AT 400 WORDS)

Extensive spinal hyperostosis in a patient receiving isotretinoin--progression after 4 years of etretinate therapy

A patient with Darier's disease was discovered to have persistent, asymptomatic cervical and thoracic spinal hyperostoses after receiving isotretinoin for 7 years. The spinal abnormalities have remained asymptomatic but have now progressed following 4 years of etretinate therapy. The development of skeletal abnormalities, in particular spinal hyperostosis, is well-documented in patients receiving the synthetic retinoid, isotretinoin (Accutane, Roaccutane). The occurrence of extraspinal tendon and ligament calcification has been emphasized following long-term therapy with etretinate (Tegison, Tigason), but the relationship between etretinate and spinal hyperostosis is less certain, there being a need for a long-term, prospective, appropriately controlled investigation of patients receiving etretinate. We report a patient with Darier's disease who was discovered to have prominent, asymptomatic cervical and thoracic spinal hyperostoses after receiving isotretinoin for 7 years. Subsequent treatment with etretinate for 4 years did not prevent progression of the spinal abnormalities.

Retinyl acetate-induced arthritis in C3H-A(vy) mice

Severely impaired musculoskeletal mobility in C3H-A(vy) mice was noted during a pharmacologic trial evaluating the antitumorigenic properties of retinyl acetate (RAc). To determine the etiology of this impairment, we studied 103 female C3H-A(vy) mice that were fed RAc in daily doses of 75-300 micrograms or placebo and were killed after 3-16 months. Whole-body radiographs and histologic sections of the hindlimbs were scored for presence and severity of arthritis. C3H-A(vy) mice treated with RAc in any dose had a significantly higher incidence of arthritis than placebo-treated mice. Histologic evidence of enthesopathic disease closely paralleled the radiographic changes and ranged from small enthesophytes at tendinous and capsular insertions to complete periarticular bony bridging. Articular cartilage was not grossly affected. The incidence and severity of arthritis were significantly correlated with the total dose of RAc administered. The bony metaplasia induced by RAc was similar to the pathologic changes caused by other retinoids. This model may be useful for studying the pathogenesis of periarticular bone formation in diffuse idiopathic skeletal hyperostosis and related syndromes.

A retrospective study of bone changes in adults treated with etretinate

Ninety patients aged 17 to 80 years were treated with etretinate for disorders of keratinization and were studied for bone changes. The treatment lasted from 0.1 to 7.9 years, mean 2.4 years. The average dosage of etretinate was 0.57 mg/kg/day (range 0.21 to 1.32 mg/kg/day), and the total dose was 31 gm (range 1 to 197 gm). Standard radiographs of the axial and peripheral skeleton were evaluated. The films of 44 patients showed skeletal abnormalities such as periosteal thickening, hyperostosis of the vertebral column, disk degeneration, osteoporosis, calcification of the spinal ligaments, and slender long bones. The present data indicate that the risk of skeletal disorders in adults treated with etretinate is significant (44 of 90), but that the severity of changes is minor.

Skeletal hyperostosis and extraosseous calcification in patients receiving long-term etretinate (Tigason)

In an ongoing study of patients on long-term etretinate (Tigason) therapy, 13 patients with a congenital or inherited disorder of keratinization and 10 patients with psoriasis were examined to investigate the incidence of, and the factors associated with, skeletal hyperostosis. Skeletal scintigraphy, plain radiographs, haematological and biochemical analyses were performed. Using all criteria, 7 of 13 patients with a congenital or inherited disorder of keratinization showed evidence of hyperostosis. No single investigation was able to detect all these cases; in particular, skeletal scintigraphy was positive in only nine of the 13 patients who showed hyperostosis. Eleven of the 13 patients with hyperostosis gave a history of musculoskeletal symptoms compared with three of the 10 patients without hyperostosis. There was no clear association with total dose or duration of treatment. Serum chemistry and haematological studies were normal. In two patients the 24-h urinary calcium excretion was significantly elevated, an abnormality which has not been described previously. Annual lateral thoracic spine radiographs with additional views of symptomatic areas are recommended for patients on long-term etretinate therapy.

Adverse effects of retinoids

Oral retinoids, synthetic derivatives of vitamin A, have been used in the treatment of various dermatoses over the last decade. The most useful drugs have been isotretinoin (13-cis-retinoic acid) for nodulocystic acne and etretinate for psoriasis vulgaris. Retinoids are also effective in the treatment of papulosquamous dermatoses other than psoriasis (i.e. inherited disorders of keratinisation), cutaneous T-cell lymphoma and in chemotherapy and chemoprevention of cancer. However, systemic administration of these compounds is frequently associated with mucocutaneous side effects, liver toxicity and abnormalities of serum lipid profiles, which might be related to an increased risk of coronary heart disease. Of particular concern is the teratogenic effect of all retinoids, which limits their use in women of child-bearing potential. Chronic toxicities from long term therapy with retinoids may result in skeletal abnormalities, usually mimicking diffuse idiopathic hyperostosis syndrome. Furthermore, the chronic use of retinoids in children may inhibit their growth due to premature epiphyseal closure. In contrast to other side effects of retinoids which are dose dependent and reversible upon withdrawal of the drug, it seems unlikely that bone abnormalities will resolve after discontinuation of the medication. In view of the wide spectrum of toxicities, treatment with retinoids requires appropriate selection of patients, careful consideration of the benefit to risk ratio for each individual, periodic monitoring of clinical response and laboratory tests. Clinicians should use special management techniques in order to prevent or minimize slide effects. Extensive investigations are currently being conducted in an attempt to develop new retinoids which will improve the therapeutic efficacy and reduce unwanted reactions.

Isotretinoin ingestion in a pediatric patient

Isotretinoin (13-cis-retinoic acid) is an oral synthetic vitamin A derivative used for control of acne and a variety of other dermatologic conditions. The case of a 21 month old child who accidentally ingested an estimated 1120 mg (63.3 mg/kg) of isotretinoin is presented. The patient demonstrated only minor immediate effects, consisting of facial flushing, and mild tachycardia, tachypnea, and hypertension, all of which resolved over 24 hours. The patient had no subsequent adverse long-term effects from the ingestion. This is the first reported ingestion of isotretinoin in a child. Short term sequelae have not been reported; long-term administration of isotretinoin may cause multiple and potentially severe reactions.

Long-term radiographic follow-up after isotretinoin therapy

We evaluated the effects of long- and short-term isotretinoin therapy on the skeletons of patients. Eight patients who were treated with isotretinoin for disorders of keratinization received frequent radiographic evaluations for 4 to 9 years. Seven patients developed multiple hyperostoses at the spine and extremities. Hyperostoses increased in size and number over the course of therapy, although relatively few sites were symptomatic. Hyperostoses typically developed first in the spine and later in the extremities, where both bilaterally symmetric and asymmetric involvement was observed. After 5 years of therapy one patient did not develop hyperostosis. In a group of nine patients who received a relatively high dose of isotretinoin in 1982 for the treatment of acne, two patients developed tiny, asymptomatic hyperostoses. One patient had hyperostoses 1 year after isotretinoin therapy, which remained unchanged 3 years later, whereas the other patient had one hyperostosis 4 years after therapy had been stopped. Although we suspect that these hyperostoses were retinoid induced, they should not be of concern for the patient needing routine isotretinoin therapy for the treatment of cystic acne.

Adverse reactions to isotretinoin. A report from the Adverse Drug Reaction Reporting System

Between October 1982 and June 1985 the Adverse Drug Reaction Reporting System received reports of 104 suspected adverse reactions occurring in 93 patients who took isotretinoin. Adverse reactions involving the skin and mucous membranes (29 reports), central nervous system (23), musculoskeletal system (12), pregnancy (11), and eyes (8) were most commonly reported. Severe headache was the most frequently reported adverse reaction (15 reports). In four cases headaches were attributed to pseudotumor cerebri. Some of the reported reactions, for example, a disulfiram (Antabuse)-like reaction and oculogyric crisis, have not been described previously in the literature. Other reports, such as congenital malformations, serve to emphasize some of the serious reactions that are known to occur. These spontaneous reports of adverse reactions associated with isotretinoin use, together with the literature we review, may help alert physicians to the diverse spectrum of adverse reactions that may develop in patients taking isotretinoin.

Bone changes in children on long-term treatment with etretinate

Ten children with disorders of keratinization (ichthyosis, 4, pityriasis rubra pilaris, 2, psoriasis, 2, and palmoplantar keratoderma, 2) were treated with etretinate for 0.5 to 9.6 years. The children ranged from 1.5 to 15.7 years of age. The total dose of etretinate ranged from 700 to 52,596 mg and the maintenance dose, from 0.21 to 0.86 mg/kg/day. Radiographic skeletal surveys were performed at various stages during treatment or following treatment. Bone abnormalities were found in eight children. Six children had periosteal thickening, two periosteal bone resorption, two osteoporosis, three disc narrowing, and one slender long bones. Compared with age- and sex-matched normal controls, the children had decreased cortical bone thickness of the second left metacarpal bone. The children's physical growth and laboratory investigations were normal. We recommend that children on long-term etretinate therapy be investigated regularly for bone changes.

Extraspinal tendon and ligament calcification associated with long-term therapy with etretinate

Isotretinoin, a synthetic retinoid that has been prescribed for over 500,000 patients with cystic acne, has been associated with both spinal hyperostosis and a disorder similar to diffuse idiopathic skeletal hyperostosis. We describe a syndrome of tendon and ligament calcification, primarily in extraspinal locations, that we have observed after long-term therapy for psoriasis and disorders of keratinization with etretinate, another synthetic retinoid. Of 38 patients who had received etretinate (average dose, 0.8 mg per kilogram of body weight per day; average duration, 60 months), 32 (84 percent) had radiographic evidence of extraspinal tendon and ligament calcification. The most common sites of involvement were the ankles (29 patients [76 percent]), pelvis (20 patients [53 percent]), and knees (16 patients [42 percent]); spine involvement was uncommon in this group of etretinate-treated patients. Involvement tended to be bilateral and multifocal. Fifteen (47 percent) of the 32 affected patients had no bone or joint symptoms at the sites of radiographic abnormality. Thus, tendon and ligament calcification can occur without vertebral involvement as well as in association with it (for example, as part of the spectrum of diffuse idiopathic skeletal hyperostosis). We have identified extraspinal tendon and ligament calcification as a toxic effect that is commonly associated with long-term etretinate therapy.

Retinoid-induced ossification of the posterior longitudinal ligament

Vitamin A and its synthetic congeners are known to produce a variety of skeletal abnormalities in patients on prolonged treatment with these medications. Two patients are described who developed posterior longitudinal ligament ossification following treatment with the synthetic retinoid 13-cis-retinoic acid. In both cases, this finding became apparent after other retinoid-induced skeletal abnormalities were observed and was less marked than the ossification of the anterior longitudinal ligament. Although spinal cord compression did not occur in our patients, patients on long-term retinoid therapy should be carefully observed for this complication.

Etretinate: management of keratoma hereditaria mutilans in four family members

We are reporting four family members, spanning three generations, who were treated with etretinate for keratoma hereditaria mutilans. All four patients presented with mutilating keratoderma of the palms and soles, and all demonstrated remarkable benefit from the medication. In addition, in the most severely affected individual, several fingers had well-established pseudoainhums that resolved during therapy.

Etretinate therapy in children with severe keratinization defects

Keratinization defects can be very severe and disfiguring diseases. The development of retinoids such as etretinate has provided us with an effective symptomatic form of oral therapy for these skin conditions. Based on our own experience, we briefly outline the therapeutic potential of etretinate in various keratinization defects (lamellar ichthyosis, Netherton syndrome, Sjögren-Larsson syndrome, mal de Meleda and juvenile pityriasis rubra pilaris). The toxicology of etretinate is reviewed with special regard to the treatment of children. Bone changes such as premature closure of the growth line or other unacceptable side-effects have so far not been observed. Guidelines for patient selection and for the safe treatment of children are given.