Extensive cutaneous hyperpigmentation caused by minocycline

Minocycline-induced retinal pigment epithelium hyperpigmentation masquerading as age-related macular degeneration: Case presentation and proposed mechanism

Purpose

We describe the case of an 80-year-old man with bilateral minocycline-induced retinal pigment epithelium (RPE) hyperpigmentation, which initially masqueraded as AMD. Secondarily, using multimodal imaging features, we propose a mechanism for the development of minocycline-induced RPE hyperpigmentation.

Observations

The patient was referred with concern for AMD given the presence of macular drusenoid deposits on optical coherence tomography. However, funduscopic evaluation showed dense granular parafoveal hyperpigmentation, with a diffuse slate-colored hyperpigmentation throughout the peripheral fundus. Short-wavelength fundus autofluorescence of the macula disclosed no irregularities (as would be expected with drusen) while on near-infrared reflectance (NIR) imaging, numerous hyperreflective foci were noted corresponding to the hyperpigmented granules observed clinically (as would instead be seen with melanin deposits). Clinical examination was notable for blue-gray hyperpigmentation of the lower and upper extremities, as well as of the face, periorbital skin, and sclera. Upon further questioning, the patient disclosed daily oral minocycline use for 15 years for acne rosacea, confirming a diagnosis of minocycline-induced hyperpigmentation of the RPE.

Conclusions

Multimodal imaging can be useful for differentiating minocycline-induced RPE hyperpigmentation from similar masquerade entities. Timely diagnosis can prevent progressive vision loss.

Generalized type II minocycline-induced pigmentation: A case report

Minocycline-induced pigmentation is a rare dermatological condition that primarily affects the skin and thyroid gland, oral mucosa, nails, teeth, bones, and sclera leading to grayish-blue pigmentation in these areas. Early identification, discontinuation of the drug, and laser treatment are crucial in managing this condition. We reported a case involving a 72-year-old Chinese woman who developed diffuse blue-brown pigmentation after 1 year of minocycline treatment for pemphigus vulgaris. Histological examination revealed multiple pigment-laden macrophages and free pigment in the dermis at the skin lesions. According to our review of the literatures, the generalized skin involvement made our case very rare in comparison with those previously reported of Chinese patients.

Blue Nail Discoloration: Literature Review and Diagnostic Algorithms

Blue nail discoloration is a distinctive clinical presentation, and diagnosis is challenging given the broad differential diagnosis. A comprehensive review of the literature describing blue discoloration of one or multiple nails was performed using the PubMed, Embase, Scopus, and Web of Science databases. A total of 245 publications were included and grouped based on involvement of a single nail (monodactylic) or multiple nails (polydactylic). Monodactylic blue discoloration was associated with tumors or benign nevi, most commonly glomus tumors, followed by blue nevi and less commonly melanomas. Polydactylic blue discoloration was frequently associated with medications (such as minocycline, zidovudine, and hydroxyurea), toxic and exogenous exposures (such as silver), and other medical conditions (such as HIV/AIDS and systemic lupus erythematous). Patients presenting with blue nail discoloration warrant a thorough history, physical examination, and workup to rule out malignancy, systemic disease, or toxic exposure. We present diagnostic algorithms for monodactylic and polydactylic blue nail discoloration to guide workup and treatment plans.

Doxycycline-Associated Hyperpigmentation: A Case Report and Literature Review

Drug-induced hyperpigmentation is an adverse cutaneous effect; it has been associated with several systemic medications. A healthy 40-year-old man developed facial and dorsal hand hyperpigmentation within two weeks of beginning doxycycline monohydrate 100 milligrams twice daily for acne. Skin pigmentation significantly diminished at a follow-up evaluation two months after discontinuing the medication. Doxycycline-associated skin hyperpigmentation, albeit uncommon, has been described in 18 patients in the literature, including our patient. The demographics included 13 males and five females ranging in age from 11 to 87 years; eight of the patients were less than 50 years old and ten of the patients were over 60 years old. Doxycycline-associated hyperpigmentation frequently occurs on the face and can occur at the site of a previous scar. In most cases, doxycycline was discontinued with the resolution of hyperpigmentation.

Black Bone Disease of the Skull

We present an image of a patient's skull characterized by dark, irregular discoloration. This was discovered incidentally in a 66-year-old man who underwent craniotomy for resection of a glioblastoma. This image demonstrates cranial black bone disease. This is an abnormal bone pigmentation associated with long-term tetracycline use, as occurred in this patient.

An Update on Drug-Induced Pigmentation

Drug-induced pigmentation accounts for up to 20% of all cases of acquired pigmentation. A thorough review of medical history and previous and ongoing medications as well as a complete skin examination can guide diagnosis. Implicated agents include alkylating/cytotoxic agents, analgesics, antiarrhythmics, anticoagulants, antiepileptics, antimalarials, antimicrobials, antiretrovirals, metals, prostaglandin analogs, and psychotropic agents, among others. Confirming true drug associations can be challenging, especially in the setting of delayed onset of pigmentation and coexisting polypharmacy.

Diffuse skin hyperpigmentation associated with chronic minocycline use in a patient with prosthetic joint infection

Cutaneous hyperpigmentation is a recognized adverse effect of chronic minocycline use occurring in up to 50% of patients. In this report we present a rare case of extensive skin hyperpigmentation involving both lower extremities in a patient receiving long term minocycline. The patient was receiving minocycline as suppression for chronic prosthetic joint infection. Risk factors associated with minocycline-induced cutaneous pigmentation (MICH) will be reviewed.

Cutaneous deposits

: The cutaneous deposition disorders are a group of unrelated conditions characterized by the accumulation of either endogenous or exogenous substances within the skin. These cutaneous deposits are substances that are not normal constituents of the skin and are laid down usually in the dermis, but also in the subcutis, in a variety of different circumstances. There are 5 broad categories of cutaneous deposits. The first group includes calcium salts, bone, and cartilage. The second category includes the hyaline deposits that may be seen in the dermis in several metabolic disorders, such as amyloidosis, gout, porphyria, and lipoid proteinosis. The third category includes various pigments, heavy metals, and complex drug pigments. The fourth category, cutaneous implants, includes substances that are inserted into the skin for cosmetic purposes. The fifth category includes miscellaneous substances, such as oxalate crystals and fiberglass. In this article, the authors review the clinicopathologic characteristics of cutaneous deposition diseases, classify the different types of cutaneous deposits, and identify all the histopathologic features that may assist in diagnosing the origin of a cutaneous deposit.

Mechanism of pigmentation by minocycline in murine B16 melanoma cells

Long-term treatment with minocycline is known to induce pigmentation or discoloration in tissues but how remains unclear. We investigated the mechanism of pigmentation using B16 melanoma cells. First, we confirmed that intracellular melanin levels increased on minocycline treatment. Then, using the reverse transcriptase-polymerase chain reaction (RT-PCR), we found the expression of mRNA of tyrosinase, tyrosinase-related protein (TRP)-1 and TRP-2, to also be significantly increased by treatment with minocycline at 5 µg/ml for 72 h. These results suggest that the minocycline-induced stimulation of melanogenesis occurs at the transcriptional level. Western-blotting revealed slight phosphorylation of extracellular signal-regulated kinase (ERK) 30-60 min after the minocycline treatment. The mitogen-activated protein kinase kinase 1/2 (MEK1/2) inhibitor U0126 and the p38 inhibitor SB203580 were used to examine the signaling pathway associated with the mRNA expression of tyrosinase, TRP-1, or TRP-2 when B16 melanoma cells were treated with minocycline. The SB203580 inhibited the mRNA expression of tyrosinase and TRP-1, suggesting the minocycline-induced melanogensis occurred via a p38 signaling pathway.

Subantimicrobial Dose Doxycycline for Acne and Rosacea

Acne vulgaris and rosacea present therapeutic challenges due to their chronicity, potential for disfigurement, and psychosocial impact. Although pathophysiologically distinct, both conditions have major inflammatory components. Consequently, topical and systemic antimicrobial agents are routinely prescribed for extended periods. Emergence of resistant strains of Propionibacterium acnes, adverse events, and compliance issues associated with chronic systemic tetracycline use have led to new treatment approaches. At subantimicrobial doses, tetracyclines reduce inflammation via anticollagenolytic, antimatrix-degrading metalloproteinase, and cytokine down-regulating properties. Subantimicrobial dose (SD) doxycycline (Periostat 20 mg) has clinical utility in periodontitis and has been investigated in a double-blind, placebo-controlled trial in the treatment of moderate facial acne as well as in an open label study in the treatment of rosacea. The results of subantimicrobial dose doxycycline treatment in early trials support its benefits and further investigation in acne and rosacea.

Safety of doxycycline and minocycline: a systematic review

OBJECTIVE

The goal of this review was to summarize the available literature covering the safety profiles of oral doxycycline and minocycline.

METHODS

Scientific literature published between 1966 and August 2003 was searched using the MEDLINE, EMBASE, and Biosis databases (search terms: minocycline or doxycycline, each paired with adverse reaction, adverse event, and side effect, and doxycycline or minocycline with the limits English language, human, and clinical trials). Safety information was collected from case reports and clinical trials. Adverse event (AE) rates in the United States were calculated by comparing data from the MedWatch AE reporting program used by the US Food and Drug Administration (FDA) with the number of new prescriptions dispensed for each drug from January 1998 to August 2003.

RESULTS

Between 1966 and 2003, a total of 130 and 333 AEs were published in case reports of doxycycline and minocycline, respectively. In 24 doxycycline clinical trials (n = 3833) and 11 minocycline trials (n = 788), the ranges in incidence of AEs were 0% to 61% and 11.7% to 83.3%, respectively. Gastrointestinal AEs were most common with doxycycline; central nervous system and gastrointestinal AEs were most common with minocycline. From January 1998 to August 2003, the FDA MedWatch data contained 628 events for doxycycline and 1099 events for minocycline reported in the United States. Approximately 47,630,000 doxycycline and 15,234,000 minocycline new prescriptions were dispensed in the United States during that period, yielding event rates of 13 per million for doxycycline and 72 per million for minocycline, based on FDA data.

CONCLUSIONS

Between 1998 and 2003, doxycycline was prescribed 3 times as often as minocycline. The incidence of AEs with either drug is very low, but doxycycline had fewer reported AEs. Although more head-to-head clinical trials are needed for a direct comparison of AE frequency, these preliminary data from separate reports suggest the possibility that AEs may be less likely with doxycycline than minocycline.

Minocycline hyperpigmentation isolated to the subcutaneous fat

We present a 15-year-old girl with bilateral lower extremity discoloration of one-year duration while taking minocycline for acne vulgaris. The clinical characteristics best supported type II minocycline hyperpigmentation, but the histology revealed that the pigmentation was solely limited to the subcutaneous adipose tissue, completely sparing the dermis. Special stain for iron was negative. This is the first case to our knowledge with pigment exclusively located in the subcutaneous fat and with the unusual finding of a negative stain for iron.

Low-intensity indocyanine-green laser phototherapy of acne vulgaris: pilot study

Near infrared (NIR) diode laser low-intensity (soft) phototherapy with the topical application of indocyanine green (ICG) has been suggested for treatment of acne vulgaris. Twelve volunteers with acne lesions on their faces and/or backs were enrolled in the experiment. Skin areas of the subjects that were 4 x 5 cm2 were stained with ICG solution for 5 min before laser irradiation (803 nm) at a power density up to 50 mW/cm2 for 5 to 10 min. For 75% of the subjects, a single treatment was provided and for the other 25%, eight sequential treatments over a period of a month were carried out. Observations a month after the completion of the treatment showed that only the multiple treatments with a combination of ICG and NIR irradiation reduced inflammation and improved the state of the skin for a month without any side effects. A month after treatment, the improvement was about 80% for the group receiving multiple treatments. Single treatments did not have a prolonged effect.

Oral mucosal pigmentation secondary to minocycline therapy: report of two cases and a review of the literature

Minocycline is a semisynthetic broad-spectrum antimicrobial agent that was first introduced into clinical practice in 1967. The most common use of minocycline is for the long-term treatment of acne vulgaris. A well-recognized side effect of minocycline treatment is pigmentation, which has been reported in multiple tissues and fluids including thyroid, skin, nail beds, sclera, bone, and teeth. While there have been several reports of oral pigmentation following minocycline therapy, these have been, for the most part, pigmentation of the underlying bone with the overlying oral mucosa only appearing pigmented. We report two cases of actual pigmented oral mucosal lesions on the hard palate secondary to minocycline therapy with the accompanying histopathology, followed by a discussion of minocycline-induced oral pigmentation and a differential diagnosis of these lesions.

A new type of minocycline-induced cutaneous hyperpigmentation

Pigmentary disorders are recognized adverse effects of the semi-synthetic tetracycline derivative antibiotic, minocycline. Three distinct types of minocycline-induced cutaneous pigmentation have been described. Type I, blue-black pigmentation confined to sites of scarring or inflammation on the face; Type II, blue-grey circumscribed pigmentation of normal skin of the lower legs and forearms; and Type III, diffuse muddy brown pigmentation of normal skin accentuated in sun-exposed areas. We report two patients with acne vulgaris with a fourth type of minocycline-induced cutaneous pigmentation. They presented with circumscribed blue-grey pigmentation within acne scars confined to the back. Histology showed pigment within dendritic cells, and extracellularly throughout the dermis. Histochemistry identified a calcium containing melanin-like substance. Iron was absent. Immunohistochemistry confirmed some pigment-containing cells to be macrophages. Electron microscopy demonstrated electron-dense granules, free and membrane-bound, within macrophages and fibroblast-like cells. Energy-dispersive X-ray analysis confirmed the presence of calcium. Iron was absent. This fourth type of cutaneous minocycline hyperpigmentation may be a variant of Type I, but based on clinical, pathological and microanalytical differences, appears to be a new entity. The pigment may be a drug metabolite-protein complex chelated with calcium, or an insoluble minocycline-melanin complex. We propose a classification of cutaneous minocycline pigmentation based on clinico-pathological criteria.

Persistent post-sclerotherapy pigmentation due to minocycline. Three cases and a review of post-sclerotherapy pigmentation

BACKGROUND

Post-sclerotherapy pigmentation, usually overlying the treated veins and independent of any drug ingestion, is common. This pigmentation is brown and represents haemosiderin and sometimes melanin as well. It usually slowly fades over a period of months, only uncommonly persisting for years. Cutaneous pigmentation due to minocycline ingestion is a known but rare adverse effect. It usually appears as a round or irregular shaped patch that is dark blue to black, representing minocycline moieties and iron complexes. Its persistence for years is common. Clinically and histopathologically, these two causes of pigmentation are quite distinct. In the absence of ulceration, minocycline pigmentation koebnerised by sclerotherapy has not previously been reported.

AIMS

To determine the nature of the pigmentation appearing in three patients who had been taking minocycline at the time, or shortly after, they had received sclerotherapy. Clinically, although this pigmentation had the usual distribution observed after sclerotherapy, it was persistent and appeared dark blue to black.

RESULTS

The persistent post-sclerotherapy linear pigmentation observed in all three patients had the characteistics of minocycline pigmentation.

CONCLUSIONS

This is the first report of such minocycline-aggravated post-sclerotherapy pigmentation. Persistent post-sclerotherapy pigmentation caused by minocycline is a risk associated with ingestion of this drug. Patients need to be warned of this risk because, unlike post-sclerotherapy pigmentation that develops in the absence of drug ingestion, minocycline-aggravated post-sclerotherapy pigmentation may persist for years.

Drug-induced skin pigmentation. Epidemiology, diagnosis and treatment

Drug-induced pigmentation represents 10 to 20% of all cases of acquired hyperpigmentation and this hypothesis must be systematically raised in unexplained pigmented lesions especially in elderly people. The pathogenesis of drug-induced pigmentation is variable according to the causative medication and can involve an accumulation of melanin, sometimes following a nonspecific cutaneous inflammation and often worsened by sun exposure, an accumulation of the triggering drug itself, a synthesis of special pigments under the direct influence of the drug or deposits of iron following damage to the dermal vessels. The influence of sun exposure is usually obvious in most cases, either by sun-induced melanin synthesis stimulation with formation of complexes between melanin and the causative drug or by transformation of the drug in visible particles usually taken up by dermal macrophages under the influence of sunlight. The main drugs implicated in causing skin pigmentation are nonsteroidal anti-inflammatory drugs, antimalarials, amiodarone, cytotoxic drugs, tetracyclines, heavy metals and psychotropic drugs. Clinical features are very variable according to the triggering molecule, with a large range of patterns and shades which are sometimes more or less reminiscent of the culprit drug. Histological findings are very variable as well but the colored particles are often concentrated within dermal macrophages which are sometimes localized in a distinctive fashion with respect to dermal structures such as vessels or adnexes. Treatment is often limited to sun-avoidance or interruption of treatment with the offending drug but laser therapy recently gave rise to hope of a cure in some cases. These measures are often followed by a fading of the lesions but the pigmentation may last for a long time or may even become permanent in a small percentage of patients.

Perinuclear antineutrophilic cytoplasmic antibody-positive cutaneous polyarteritis nodosa associated with minocycline therapy for acne vulgaris

Minocycline is an oral antibiotic widely used for the long-term treatment of acne vulgaris. Unusual side effects of this medication include two overlapping autoimmune syndromes: drug-induced lupus and autoimmune hepatitis. In addition, in a few patients livedo reticularis or subcutaneous nodules have developed in association with arthritis and serum perinuclear antineutrophil cytoplasmic antibodies (P-ANCA) during long-term minocycline therapy. We report the cases of two young women receiving long-term minocycline therapy (>3 years) in whom P-ANCA-positive cutaneous polyarteritis nodosa developed. Both patients presented with a violaceous reticulated pattern on the lower extremities. Histologic examination of biopsy specimens from a reticulated area and a subcutaneous nodule showed necrotizing vasculitis of medium-sized arteries in the deep dermis, consistent with the diagnosis of polyarteritis nodosa. The cutaneous lesions rapidly resolved on discontinuation of minocycline and initiation of prednisone therapy. A high index of suspicion and testing for antineutrophil cytoplasmic antibody in addition to the standard antinuclear antibody panel can facilitate diagnosis of minocycline-related autoimmune disorders.

Treatment of minocycline-induced cutaneous pigmentation with the Q-switched Alexandrite laser and a review of the literature

Cutaneous pigmentation associated with minocycline ingestion is an unusual adverse effect for which few treatments have been described. Within the past few years, treatment with different Q-switched lasers has been reported in the literature. The purpose of this therapeutic intervention was to determine whether the Q-switched Alexandrite laser could clinically and histologically improve pigmentation associated with minocycline ingestion. A patient with type II minocycline pigmentation was treated with the Q-switched Alexandrite (755 nm) laser and then evaluated clinically and histologically to determine the outcome of this intervention. Treatment with the Q-switched Alexandrite (755 nm) laser provided excellent clinical and histologic clearing of minocycline pigmentation. One year after completion of laser treatment, the skin has remained clinically clear with no recurrence. The Q-switched Alexandrite laser (755 nm) should be considered for treatment of type II minocycline pigmentation.

Minocycline-induced hyperpigmentation: treatment with the Q-switched Nd:YAG laser

BACKGROUND AND OBJECTIVE

Cutaneous hyperpigmentations are well-documented, but nevertheless rare side-effects of high-dose or long-term minocycline therapy. The pigmental changes, may last for years, even though therapy has been abrogated. To date, no safe and effective therapy has been described to target this cosmetically disturbing sequela.

STUDY DESIGN/MATERIALS AND METHODS

A 57-year-old female patient with extensive pigmental changes of the face due to long-term minocycline therapy was treated in eight consecutive sessions with the Q-switched Nd:YAG-laser (1,064-nm wavelength, 5- to 7-nsec impulse length).

RESULTS

A 90% resolution of the pigmentation could be achieved after five treatments. After the last session the lesions were completely gone; no hypopigmentation scars, or other side-effects were observed.

CONCLUSION

Treatment with the Q-switched Nd:YAG laser seems to be an effective, safe, and easily applicable strategy for the therapy of minocycline-induced hyperpigmentations.

Benefits and risks of minocycline in rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory disease affecting about 1% of the adult population. The pathophysiology of rheumatoid arthritis remains incompletely understood. An infectious aetiology of the disease has long been postulated, but not proved. Despite insufficient evidence for the infectious nature of this disorder, several antibacterials, such as sulfa compounds, tetracyclines and rifampicin, have been investigated in the treatment of rheumatoid arthritis. In the last few years, minocycline, a semi-synthetic derivative of tetracycline, has been extensively studied as a therapeutic agent for rheumatoid arthritis. The antirheumatic effect of minocycline can be related to its immunomodulatory and anti-inflammatory, rather than to its antibacterial properties. Its efficacy in rheumatoid arthritis has been reported in 2 open trials and in 3 double-blind controlled studies. The first 2 double-blind studies, 1 in The Netherlands and 1 in the US, were performed in patients with advanced disease. Both studies showed a modest, but statistically significant improvement in the clinical parameters of disease activity and in the erythrocyte sedimentation rate in the minocycline-treated patients. The US study also reported that patients in the minocycline group developed fewer erosions than those in the placebo group. This finding supports the role of minocycline as a disease modifying agent. The common adverse effects of minocycline reported in these 2 studies included gastrointestinal adverse effects, dizziness, rash and headaches. Less common adverse effects were intracranial hypertension, pneumonitis, persistent skin and mucosal hyperpigmentation, lupus-like syndrome and acute hepatic injury. The third double-blind study enrolled only seropositive rheumatoid arthritis patients with early disease (less than 1 year duration), and showed very encouraging results of significant improvement in the disease activity parameters in the minocycline treated group of patients. The same authors later reported that about half of these patients were in or near remission after 3 years of follow up. No adverse effects were reported in this study. Summarising the data of these 3 double-blind studies, we may conclude that minocycline may be beneficial in patients with rheumatoid arthritis, especially when given early in the disease course or in patients with a mild disease.

Azithromycin compared with minocycline in the treatment of acne comedonica and papulo-pustulosa

This open study was conducted in 72 outpatients with acne vulgaris, to compare the clinical efficacy and tolerability of azithromycin and minocycline. Azithromycin was administered as a single oral dose (500 mg/day) for 4 days in four cycles every 10 days and minocycline was administered 100 mg daily for 6 weeks. Improvement was assessed 6 weeks after initiation of treatment with a four-graded scale. A satisfactory clinical response was observed in 75.8% of the patients treated with azithromycin and in 70.5% of those treated with minocycline. There were no significant differences between these two acne treatments in terms of reduction of the number of lesions (p> 0.05). Both agents were well tolerated and mild side effects were reported in 10.3% of azithromycin and 11.7% of minocycline treated patients. We conclude that azithromycin is at least as clinically effective and well tolerated as minocycline as treatment of facial comedonic and papulopustular acne.

Minocycline-induced cutaneous pigmentation

BACKGROUND

Minocycline-induced cutaneous pigmentation is an adverse effect that may be more common than is generally realized. It is usually reported in patients undergoing chronic minocycline therapy for acne vulgaris.

OBJECTIVE

The case of a 69-year-old woman taking minocycline for rheumatoid arthritis is presented, and its differential diagnosis discussed in order to characterize the clinical features of minocycline-induced cutaneous pigmentation.

CONCLUSION

Patients undergoing minocycline therapy for rheumatoid arthritis may develop bluish-grey pigmentation over the legs and forearms. Cutaneous pigmentation is a well recognized adverse effect of minocycline therapy that is usually reported in young patients on chronic therapy for acne vulgaris. However, the antiinflammatory properties of minocycline have also made it useful in the management of various inflammatory conditions such as rheumatoid arthritis.1 We report the case of a 69-year-old woman who developed progressive cutaneous pigmentation, affecting mainly the legs, approximately 3 months after beginning minocycline therapy for rheumatoid arthritis.

Pigmentary diseases

Abnormalities of pigmentation are common and frequently produce great concern in patients presenting to primary care physicians. Although many pigmentary changes arise as a consequence of inflammatory skin disorders, it is important to differentiate a primary skin disease from postinflammatory changes. Early recognition of a pigmentary disease allows the clinician to begin appropriate therapy at a stage when medical intervention may be more effective. Although many skin disorders are mainly of cosmetic concern, the condition may be devastating psychologically, requiring the clinician to be sensitive to the overall impact of the disorder and treat it accordingly.

Minocycline-induced scleral, dental, and dermal pigmentation

PURPOSE

To report a case of scleral discoloration secondary to minocycline therapy.

METHOD

Case report of a patient referred to a university-based cornea and external disease clinic.

RESULTS

The patient had been treated with oral minocycline therapy for adult facial acne for 12 years when she began to develop bilateral blue-gray discoloration of the sclera as well as of the teeth, hard palate, ears, nail beds, and skin.

CONCLUSIONS

Chronic systemic minocycline therapy may induce scleral pigmentary changes. The mechanism of discoloration and the long-term natural history upon cessation of minocycline are unclear.

Minocycline-induced scleral pigmentation

PURPOSE

Minocycline is a commonly used drug in the management of acne and rosacea. Four individual cases of oral minocycline-induced scleral pigmentation are reported in the dermatologic literature. This is the first report in the ophthalmic literature and will add three new cases of probable minocycline-induced scleral pigmentation.

MATERIALS AND METHODS

Data on minocycline from the spontaneous reporting systems of the National Registry of Drug-Induced Ocular Side Effects, Food and Drug Administration, World Health Organization, and Lederle Laboratories were reviewed as to minocycline-related scleral pigmentation. Photographs, published cases, discussions with the examining ophthalmologists, and the personal observation of one patient (case 1) are the basis of the authors' conclusions.

RESULTS

Seven cases of probable oral minocycline-induced scleral pigmentation are presented. These changes may or may not be associated with minocycline-induced pigmentary changes in other tissues, such as the skin, teeth, fingernails, bone, thyroid, or mucosa. The characteristic scleral pattern is a blue-gray 3- to 5-mm band starting at the limbus, which usually is enhanced in the palpebral aperture, possible due to the photosensitizing properties of the drug.

CONCLUSIONS

Oral minocycline can cause scleral pigmentation. This pigmentation may resolve within years, or it may be permanent.

Minocycline-induced intraoral pharmacogenic pigmentation: case reports and review of the literature

Minocycline, a semi-synthetic tetracycline antibiotic, is well documented as being associated with pharmacogenic pigmentation of various tissues in humans and other mammals. The most obvious of these are skin pigmentation, but intraorally include "green" roots of erupted teeth, "black" roots of extracted teeth, a dark stain of the crowns of fully developed teeth, and "black" alveolar bone. This article presents five cases of "black" alveolar bone with photographic documentation of its progress. It also reviews the available English language literature on this phenomenon. The incidence of minocycline staining of alveolar bone is probably 2% of that population taking the drug for 2 months or longer. Presently, minocycline is most widely used in the young adult population for the treatment of acne. With the recent interest in minocycline as a palliative treatment for rheumatiod arthritis, an entirely different population could be experiencing this effect. If minocycline use becomes widespread as a treatment for rheumatoid arthritis, it is likely that more practitioners will be asked to diagnose this sometimes striking, though apparently benign, condition. Recognition of this condition will save the practitioner and the patient from unnecessary concern and surgery.

Safety of long-term high-dose minocycline in the treatment of acne

Minocycline is widely used as a second-line antimicrobial for acne vulgaris. Some patients require doses of up to 200 mg daily to control their acne. To assess the long-term safety of minocycline when used at higher doses, 700 patients treated with minocycline at doses of 100 mg daily, 100/200 mg on alternate days and 200 mg daily, were recruited. The mean duration of treatment was 10.5 months. Side-effects were monitored and full blood count, blood urea, electrolytes and liver function tests were carried out on 200 of the 700 patients. Side-effects were recorded in 13.6%, and included vestibular disturbance, candida infection, gastrointestinal disturbance, cutaneous symptoms (pigmentation, pruritus, photosensitive rash and urticaria) and benign intracranial hypertension. Pigmentation was the only side-effect found to be significantly increased in patients taking higher doses of minocycline, as compared with lower doses (P < 0.01). All patients with pigmentation had taken a total cumulative dose of over 70 g. No significant abnormalities were found in any of the haematological and biochemical profiles. We conclude that minocycline, at doses of up to 200 mg/day, is safe, long-term, for acne, when such doses are clinically necessary.

Oral presentation of minocycline-induced black bone disease

Minocycline hydrochloride is a semisynthetic tetracycline derivative used widely for the treatment of acne vulgaris. Among its side effects is the ability to pigment many tissues particularly thyroid, skin, tooth, and bone. A case is presented in which long-term minocycline therapy (500 g taken orally over 11 years) resulted in dark bone pigmentation (black bone disease) severe enough to be visible through the alveolar and palatal mucosa. No skin or tooth pigmentation was present.

Lingual hyperpigmentation associated with minocycline therapy

Minocycline can cause hyperpigmentation of the conjunctiva, oral mucosa, and skin. Pigmentation of the oral mucosa may also be associated with a variety of endogenous or exogenous factors. Lingual pigmentation may be seen in Addison's disease, amalgam tatoo, malignant melanoma, Peutz-Jegher's syndrome, and other diseases. Two women who had isolated pigmentation of the tongue while taking minocycline are described; no other drug-induced pigmentation of their oral mucosa or skin occurred. Minocycline-induced pigmentation should be added to the differential diagnosis of isolated lingual hyperpigmentation.