Chloroquine-induced hypopigmentation of hair and freckles. Association with congenital renal failure

Chloroquine -induced hair depigmentation

A case of hair depigmentation induced by chloroquine diphosphate subacute overdosage in an 11-year-old patient with dermatomyositis is presented. Normal coloured hair growth occurred after normalisation of chloroquine dosage. A discussion on possible pathomechanisms of this phenomenon is made based on experimental data and previously reported patients with the same condition.

Identification of quinolines that inhibit melanogenesis by altering tyrosinase family trafficking

A series of quinolines, including chloroquine and quinine, were identified as potent pigmentation inhibitors through screening a compound library in murine melanocytes. Structure-activity relationship analysis indicated that 4-substituted amino groups with a tertiary amine side chain, such as chloroquine, were associated with robust inhibitory activity. In contrast to many previously identified pigmentation inhibitors, these newly identified inhibitors had no effect on either the level or the enzymatic activity of tyrosinase, the rate-limiting enzyme in melanin production. Rather, our results showed that these quinolines inhibited melanogenesis by disrupting the intracellular trafficking of tyrosinase-related proteins and lysosome-associated membrane protein 1 (Lamp-1). In treated melanocytes, tyrosinase and tyrosinase-related protein 1 accumulated in Lamp-1-positive perinuclear organelles instead of melanosomes, thus preventing melanogenesis. The depigmenting abilities of chloroquine and quinine salicylate were assessed in a human skin equivalent model (MelanoDerm). Both compounds were considerably more effective than arbutin, a widely used lightening agent. Our results indicate that quinolines may be useful agents for "cosmeceutical" skin lightening and treatment of hyperpigmentation disorders.

Hypopigmentation and Desquamation as Dermatologic Reactions to Aralen

A 55-year-old white male while on Aralen(R) (chloroquine phosphate, Sanofi-Winthrop) developed desquamation and hypopigmentation of both hands. Dermatologic manifestations of chloroquine side effects are uncommon, and the appearance of desquamation has not been reported. There were no other accountable factors that appeared to contribute to this phenomenon.

Chloroquine-induced vitiligo-like depigmentation

A 6-year-old girl of Ethiopian origin with atopic eczema from the age of 2 years is reported. Prior to a visit to her grandparents in Ethiopia, she received 250 mg chloroquine weekly as prophylaxis against malaria. Three weeks later she developed sharply demarcated depigmentation on the face, especially in the peritoneal area. On returning home to Norway, the medication was discontinued and after a few weeks the first repigmentation was noticed. Complete repigmentation was observed 1 year after cessation of chloroquine therapy.

Diffuse heterochromia of scalp hair

Heterochromia of hair is the presence of more than one distinct color of hair in the same person. A color difference between scalp hair and a mustache or sideburns is not uncommon. Pubic and axillary hair and eyebrows and eyelashes are often darker than scalp hair in a fair-haired person. Rarely, a circumscribed patch of hair of different colors occurs. However, diffuse heterochromia of black and red scalp hair has not been previously reported. We describe a father and son with this condition.

Hypopigmentation in dogs treated with an inhibitor of platelet aggregation

Hypopigmentation was the principal manifestation of systemic toxicity when the experimental platelet aggregation inhibitor, PD-89454, was orally administered to Beagle dogs for 28 days. Pigmentation changes were present in skin of nose, lips and eyelids and mucosa of hard palate. Fontana-Masson stain demonstrated decreased melanin within melanocytes and keratinocytes. Melanocytes were globoid with inconspicuous dendritic processes and had small, incompletely pigmented melanosomes that were quantitatively reduced relative to controls. Toxic mechanism of action of PD-89454, structurally distinct from known depigmenting compounds, was not established but ultrastructural findings suggest an interference in melanosome formation and/or melanization.