Contact dermatitis topical drugs

Mechlorethamine Mustargen) is a cytotoxic alkylating agent. Topical application of freshly prepared aqueous solutions are used in patients with early stages of cutaneous T-cell lymphoma. A major disadvantage to the use of this drug is the rapid induction of allergic contact dermatitis in some patients. 

Type IV Cell-mediated allergy is the mechanism involved in allergic contact dermatitis from topically applied drugs or induration of the skin at the site of an antigen injected intradermally. 

The most common adverse effects of topical retinoic acid are erythema and dryness that occur in the first few weeks of use, but these can be expected to resolve with continued therapy. Animal studies suggest that this drug may increase the tumorigenic potential of ultraviolet radiation. In light of this, patients using retinoic acid should be advised to avoid or minimize sun exposure and use a protective sunscreen. Allergic contact dermatitis to topical retinoic acid is rare. 

Plasma levels of doxepin similar to those achieved during oral therapy may be obtained with topical application the usual drug interactions associated with tricyclic antidepressants may occur. Therefore, monoamine oxidase inhibitors must be discontinued at least 2 weeks prior to the initiation of doxepin cream. Topical application of the cream should be performed four times daily for up to 8 days of therapy. The safety and efficacy of chronic dosing has not been established. Adverse local effects include marked burning and stinging of the treatment site which may necessitate discontinuation of the cream in some patients. Allergic contact dermatitis appears to be frequent, and patients should be monitored for symptoms of hypersensitivity. 

Tea Tree (Melaleuca alternifolia) Uses Rx of superficial wounds (bacterial, viral, fungal, insect bites, minor burns, cold sores, acne Action Broad-spectrum antibiotic activity against E. coli, S. aureus, C. albicans Available forms Topical creams, lotions, oint, oil apply topically PRN Notes/SE Ataxia, contact dermatitis, D, drowsiness, GI mucosal irritation Interactions Effects OF drugs that affect histamine release EMS effects of Benadryl Valerian (Valeriana officinalis) Uses Anxiolytic, antispasmodic, dys-menorrheal, restlessness, sedative Action Inhibits uptake stimulates release of GABA, which T GABA concentration extracellularly causes sedation Available forms Ext 400-900 mg PO 30 min < hs, tea 2-3 g (1 tsp of crude herb) qid, PRN, tine 3-5 mL (1/2-1 tsp) (1 5 ratio) PO qid, PRN Efficacy Probably effective sedative (reduces sleep latency) Notes/SE GI upset, HA, insomnia, N/V, palpitations, restlessness, vision changes Interactions T Effects OF barbiturates, benzodiazepines, opiates, EtOH, catnip, hops, kavakava, passion flower, skullcap effects OF MAOIs, phenytoin, warfarin EMS T Effects of benzodiazepines and opiates abruptly D/C may cause withdrawal symptoms... 

Corticosteroids have a range of activity. They have potent antiinflammatory and immunosuppressive activity. Many synthetic drugs are available as corticosteroids. In appropriate doses, these are used as replacement therapy in adrenal insufficiency. The topical application of corticosteroids is safer when compared with systemic use. Corticosteroids should be used in smaller doses for the shortest duration of time. A high dose may be used for life-threatening syndromes or diseases. A tapering pattern of withdrawal should be followed to avoid complications of sudden withdrawal. Systemic therapy is indicated in a variety of conditions. These are administered by intraarticular injections with aseptic conditions for rheumatoid arthritis and osteoarthritis. In skin diseases, such as eczema, contact dermatitis, and psoriasis, corticosteroids are used topically. In some cases, steroids are combined with antimicrobial substances such as neomycin. 

Type IV reactions occur when T-cells bind to a specific antigen, thereby causing the release of cytokines. The onset of these reactions may be delayed by more than 12 hours. Topical application of drugs may result in allergic contact dermatitis and photosensitivity. These reactions typically manifest initially as a skin rash but may become systemic upon subsequent exposure to the antigen. 

Irritant or allergic contact dermatitis is eczematous and is often caused by antimicrobials, local anaesthetics, topical antihistamines, and increasingly commonly by topical corticosteroids. It is often due to the vehicle in which the active drug is applied, particularly a cream. 

Holdiness MR. Contact dermatitis from topical antiviral drugs. Contact Dermatitis 2001 44(5) 265-9. 

Contact dermatitis was often observed when penicillin was used in topical formulations and still continues to be described in cases of occupational exposure to beta-lactams (218,219). The underlying mechanism is thought to involve chemical modification of antigen-presenting cells in the epidermis, leading to sensitization of drug-specific T cells (220,221). 

Hypersensitivity occurs about four times more often after topical than after oral use (45). In fact, there has been a continuous increase in chloramphenicol hypersensitivity, owing to the use of dermatological formulations (46). Allergic contact dermatitis and macular or vesicular skin rashes are usually limited to skin areas previously exposed to the drug. Contact conjunctivitis has also been reported. 

Alanko K. Topical provocation of fixed drug eruption. A study of 30 patients. Contact Dermatitis 1994 31(l) 25-7. 

Ophaswongse S, Maibach H. Topical nonsteroidal antiinflammatory drugs allergic and photoallergic contact dermatitis and phototoxicity. Contact Dermatitis 1993 29(2) 57-64. 

The overall annual incidence of severe erythema mnlti-forme (toxic epidermal necrolysis and Stevens-Johnson syndrome) is about one case per million, antibiotics being involved in 30-40% (124,125). The clinical differentiation between these syndromes can be difficult (126). Allergic contact dermatitis is usually caused by topical drugs, but is also seen in connection with ingestion, injection, or inhalation (127-129). 

In allergic contact dermatitis due to topical medicaments (6), any constituent of the formulation can be responsible for the adverse event—the vehicle, preservative, emulsifier, perfume, or the active drug. Hence, patch tests should be carried out with all active and supposedly inactive ingredients of the incriminated topical drug. 

Ozkaya-Bayazit E, Gungor H. Trimethoprim-induced fixed drug eruption positive topical provocation on previously involved and uninvolved skin. Contact Dermatitis 1998 39(2) 87-8. 

Smyth HF, Carpenter CP, Weil CS. The chronic oral toxicology of the polyethyleneglycols./ Am Pharm Assoc (Sci) 1955 44 27-30. Fisher AA. Immediate and delayed allergic contact reactions to polyethylene glycol. Contact Dermatitis 1978 4 135-138. Anonymous. Topical PEG in burn ointments. FDA Drug Bull 1982 12 25-26. 

Chen, H.H., Tseng, M.P., and Hsu, CJ. 2003. A patch test study of 27 crude drugs commonly used in Chinese topical medicaments. Contact Dermat. 49, 8-14. 

Adverse Effects. The side effects of topical minoxidil are mainly local, caused by skin irritation and contact dermatitis. Systemic side effects are uncommon because of limited percutaneous absorption, but diffuse hypertrichosis of the face and limbs has been reported with the 5% solution and was attributed to systemic absorption of the drug (84). Although topical minoxidil does not change blood pressure in healthy subjects, it increases heart rate by 3-5 beats/min and slightly increases the left ventricular end-diastolic volume, cardiac output, and left ventricular mass (85). These effects are not considered clinically significant, and the potential for cardiovascular side effects is very low. 

D. Type IV Drug Allergy Type IV allergy is a cell-mediated reaction that can occur from topical application of drugs. It results in contact dermatitis. 

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